xvEPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/2-78-042a
October 1978
Air
Stack Sampling
Technical Information
A Collection of
Monographs and Papers
Volume I
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EPA-450/2-78-042a
Stack Sampling Technical Information
A Collection of Monographs and Papers
Volume I
Emission Standards and Engineering Division
U S ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
October 1978
-------
This report has been reviewed by the Emission Standards and Engineering
Division, Office of Air Quality Planning and Standards, Office of Air, Noise
and Radiation, Environmental Protection Agency, and approved for publica-
tion. Mention of company or product names does not constitute endorsement
by EPA Copies are available free of charge to Federal employees, current
contractors and grantees, and non-profit organizations - as supplies permit
from the Library Services Office, MD-35, Environmental Protection Agency,
Research Triangle Park, NC 27711, or may be obtained, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Sprinqfield
VA22161.
Publication No. EPA-450/2-78-042a
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PREFACE
The Clean Air Act of 1970 requires the Administrator of the
Environmental Protection Agency to establish national emission standards
for new stationary sources (Section 111) and hazardous air pollutants
(Section 112). The development of these emission standards required the
concurrent development of reference test methods and procedures. The
reference test methods and procedures are published in the Federal Register
along with the appropriate regulations. -
From time to time, questions would surface concerning the methods and
procedures. In many cases, specific studies would be needed to provide
informed, objective answers. The papers and monographs resulting from these
studies were usually distributed to people involved in emission measurement;
a major method of distribution has been the Source Evaluation Society
Newsletter.
To provide a readily available resource for new and experienced personnel,
and to further promote standardized reference methods and procedures, it has
been decided to publish the papers and monographs in a single compendium.
The compendium consists of four volumes. The Table of Contents for all
four volumes is reproduced in each volume for ease of reference.
Congratulations and sincere appreciation to the people who did the
work and took the time to prepare the papers and monographs. For the most
part the work was done because of personal commitments to the development
of objective, standardized methodology, and a firm belief that attention
to the details of stack sampling makes for good data. The foresight of
Mr. Robert L. Ajax, the former Chief of the Emission Measurement Branch and
now the Assistant Director, Emission Standards and Engineering Division, in
providing the atmosphere and encouragement to perform the studies is
gratefully acknowledged. The skill and dedication of Mr. Roger Shigehara,
in providing personal supervision for most of the work, is commended.
Don R. Go'odwin
Director
Emission Standards and
Engineering Division
iii
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VOLUME I
TABLE OF CONTENTS
Method for Calculating Power Plant Emission Rate i
by R. T. Shigehara, R. M. Neulicht, and W. S. Smith
Emission Correction Factor for Fossil Fuel-Fired Steam in
Generators (C02 Concentration Approach)
by R. M. Neulicht
Derivation of Equations for Calculating Power Plant Emission 20
Rates (02 Based Method - Wet and Dry Measurements)
by R. T. Shigehara and R. M. Neulicht
Summary of F Factor Methods for Determining Emissions from 29
Combustion Sources
by R. T. Shigehara, R. M. Neulicht, W. S. Smith,
and J. W. Peeler
Validating Orsat Analysis Data from Fossil-Fuel-Fired Units 44
by R. T. Shigehara, R. M. Neulicht, and W. S. Smith
A Guideline for Evaluating Compliance Test Results 56
(Isokinetic Sampling Rate Criterion)
by R. T. Shigehara
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VOLUME II
TABLE OF CONTENTS
A Type-S Pi tot Tube Calibration Study 1
by Robert F. Vollaro
The Effect of Aerodynamic Interference Between a Type-S 24
Pi tot Tube and Sampling Nozzle on the Value of the
Pi tot Tube Coefficient
by Robert F. Vollaro
The Effects of the Presence of a Probe Sheath on Type-S 30
Pi tot Tube Accuracy
by Robert F. Vollaro
An Evaluation of Single-Velocity Calibration Technique as 48
a Means of Determining Type-S Pi tot Tube Coefficients
by Robert F. Vollaro
Guidelines for Type-S Pitot Tube Calibration 63
by Robert F. Vollaro
The Effects of Impact Opening Misalignment on the Value of 89
the Type-S Pitot Tube Coefficient
by Robert F. Vollaro
Establishment of a Baseline Coefficient Value for Properly 95
Constructed Type-S Pitot Tubes
by Robert F. Vollaro
A Survey of Commercially Available Instrumentation for the 104
Measurement of Low-Range Gas Velocities
by Robert F. Vollaro
The Use of Type-S Pitot Tubes for the Measurement of Low 122
Velocities
by Robert F. Vollaro
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VOLUME III
TABLE OF CONTENTS
Thermocouple Calibration Procedure Evaluation 1
by Kenneth Alexander
Procedure for Calibrating and Using Dry Gas Volume Meters 10
As Calibration Standards
by P. R. Westlin and R. T. Shigehara
Dry-Gas Volume Meter Calibrations 24
by Martin Wortman, Robert Vollaro, and Peter Westlin
Calibration of Dry Gas Meter at Low Flow Rates 33
by R. T. Shigehara and W. F. Roberts
Calibration of Probe Nozzle Diameter 41
by P. R. Westlin and R. T. Shigehara
Leak Tests for Flexible Bags 45
by F. C. Biddy and R. T. Shigehara
Adjustments in the EPA Nomograph for Different Pitot Tube 48
Coefficients and Dry Gas Molecular Weights
by R. T. Shigehara
Expansion of EPA Nomograph (Memo) 60
by R. T. Shigehara
EPA Nomograph Adjustments (Memo) 63
by R. T. Shigehara
Graphical Technique for Setting Proportional Sampling 65.
Flov; Rates
by R. T. Shigehara
vii
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VOLUME IV
TABLE OF CONTENTS
Recommended Procedure for Sample Trayerses in Ducts Smaller 1
Than 12 Inches in Diameter
by Robert F. -Vollaro
Guidelines for Sampling in Tapered Stacks 24
by T. J. Logan and R. T. Shigehara
Considerations for Evaluating Equivalent Stack Sampling 28
Train Metering Systems
by R. T. Shigehara
Evaluation of Metering Systems for Gas-Sampling Trains 40
by M. A. Wortman and R. T. Shigehara
An Evaluation of the Current EPA Method 5 Filtration 49
Temperature-Control Procedure
by Robert F. Vollaro
Laboratory Evaluation of Silica Gel Collection Efficiency 67
Under Varying Temperature and Pressure Conditions
by Peter R. Westlin and Fred C. Biddy
Spurious Acid Mist Results Caused by Peroxides in Isopropyl 79
Alcohol Solutions Used in EPA Test Method 8 (Memo)
by Dr. Joseph E. Knoll
Determination of Isopropanol Loss During Method 8 Simulation 80
Tests (Memo)
by Peter R. Westlin
Comparison of Emission Results from In-Stack Filter Sampling 82
and EPA Method 5 Sampling
by Peter R. Westlin and Robert L. Ajax
EPA Method 5 Sample Train Clean-Up Procedures 98
by Clyde E. Riley
vi ii
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METHOD FOR CALCULATING
POWER PLANT EMISSION RATE
By
R. T. Shigehara, R. M. Neulicht, and W. S. Smith**
Introduction
In the final State Implementation Plans submitted by all 50 States,
the District of Columbia, Puerto Rico, American Samoa, Guam, and the
Virgin Islands in response to the 1970 Clean Air Act, most of the regu-
lations for the control of particulate, sulfur dioxide, and nitrogen
oxide emissions from fuel burning sources are expressed in pounds of
emissions per million Btu of heat input (lb/10 Btu) . The Federal New
2
Source Performance Standards regulating the same pollutants from fossil
fuel-fired steam generating units of more than 250 million Btu/hr heat
input are expressed in the same terms. To arrive at this expression, the
Federal perfromance standard regulations call for the determination of the
pollutant concentration (C), the effluent volumetric flow rate (Qs), and the
heat input rate (QH). In addition, the heat input rate must be confirmed by
a material balance over the steam generator system.
The purpose of this paper is to present an alternative method for arriv-
ing with improved accuracy at the expression of lb/10 Btu called for by the
State and Federal regulations without having to determine effluent gas volu-
metric flow rate, fuel rate, or fuel heat content.
Published in Stack Sampling News 1(1): 5-9, July 1973
* Emission Measurement Branch, ESED, OAQPS, EPA
** Entropy Environmentalists, Inc.
1
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Derivation of the F-Factor Method
Standard Method
In the standard method of calculating emission rates
C Qs
where: E = pollutant emission, lb/106 Btu.
C = pollutant concentration, dry basis, Ib/scfd.
Qs = dry effluent volumetric flow rate, scfd/hr.
QH = heat input rate, 106 Btu/hr.
F-Factor Method
When the laws of conservation of mass and energy are applied, the
following must hold true:
where: Vg = theoretical dry combustion products per pound of fuel burned,
scfd/lb.
HHV = high heating value, 106 Btu/lb.
20 9 - %0
' 2_ = excess air correction factor.
20.9
Solving Equation 2 for the ratio QS/QH and substituting into Equation 1
yields:
u
r _ r i s » , 20.9 N
E ' C (HHV} (20.9 - to
-------
The amount of dry effluent gas (Vs) generated by combustion of a fossil
fuel can easily be calculated from the ultimate analysis. The high heating
value can be obtained from standard calorific determinations. The ratio, F,
between Vg and HHV can be calculated for various fossil fuels; F is the efflu-
ent gas generated per 10 Btu heat content:
F =
HHV (100)
Values for F calculated from data obtained from the literature are
summarized in Table I. Of course, this ratio can be calculated for each
specific case, but the dry effluent per 104 Btu varies no more than about
+. 3%. For this reason, these ratios will be considered as constants and
will hereafter be called "F Factors." The use of these F Factors, as will
be discussed later, eliminates the need for ultimate and calorific analyses
A list of average F Factors derived from Table I is shown in Table II.
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Table I
F Factors for Fossil Fuels
(Calculated from Data
in Literature)
Fuel
Coal
Lit.
Source
Anthracite 3
Total
or avg
4
Bituminous 3
Lignite
Total
or avg
Oil
Crude
5
6
7
8
9
10
4
3
5
11,12
4
Residuum 12
Distillate 12
Fuel
Total
or avg
Gas
Natural
11
4
13
Commercial 13
Samples,
No.
3
1
4
8
44
38
13
39
26
57
1
1
2
229
6
1
4
2
3
16
1
4
2
scfd/l'64
Btua
101.0
102.8
101.4
97.5
97.5
98.7
98.9
98.6
98.2
98.0
99.3
97.5
99.4
98.2
91.9
92.0
93.1
92.7
91.5
92.2
88.0
86.7
86.8
Max.
(+)
2.4
-
2.0
1.4
2.1
1.4
1.5
2.3
2.1
1.0
-
_
1.0
2.7
1.9
_
1.9
0.5
1.9
2.8
_
0.3
0.1
Dev.
(-)
1.2
-
1.6
1.1
2.4
1.2
1.1
1.4
1.2
1.2
-
_
1.0
3.1
2.6
_
2.1
1.5
1.3
3.0
_
0.5
0.1
propane
Commercial 13
butane
Total
or avg
2
9
89.0
87.4
0.3
2.2
0.3
1.2
aStandard conditions are 70°F, 29.92 in. Hg,
and 0% excess air.
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Table II. Average F Factors1
Fuel
Coal-anthracite
Coal-bituminous, lignite
Oil-crude, residuum, distillate, fuel oil
Gas-natural, butane, propane
F Factors
scfd/104 Btub
101.4
98.2
92.2
87.4
aDerived from Table I.
b70°F, 29.92 in. Hg., and 0% excess air.
Use of F Factors
Emission Rate Calculation
When Qs and QH are not measured or are unobtainable, F Factors can be used
to calculate E. Substituting Equation 4 into Equation 3 we obtain:
E = C F ( 209
c u r ^
^20 9 - 20 '
c.w y /o\jt%
where: F = F Factor from Table II, in scfd/104 Btu.
Equation 5 shows that E can be obtained by simply measuring the pollutant
concentration and percentage oxygen and by knowing the type of fuel being burned.
Qs and QH are no longer required.
Material Balance Check
If Qs and QH are measured, F Factors can be used to check sampling data by
comparing them with F .
where: f = ^s I20'9 ~ %02
m Q 20.9
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Fuel Analysis Check
If ultimate and proximate analyses are made, F Factors can be used
to check the accuracy of such analyses by comparing them with VS/HHV which
is the calculated amount of dry effluent gas generated per 104 Btu heat
content.
Discussion
In the present method for calculating power plant emission rates, four
separate quantities must be determined, each of which requires at least two
measurements, as shown in Table III.
Table III
Quantities and Measurements Required
For Calculation of Power Plant
Emission Rates (Regulation Method)
Quantity Used
1. Pollutant concentration, C
Quantity Measured
2. Effluent volumetric flow
rate, 0
3. Heat input rate,
a. Pollutant mass
b. Dry gas volume
a. Velocity head
b. Stack temperature
c. Stack pressure
d. Dry gas composition
(Orsat) %C02, %02, %N~
e. Moisture content (deter-
mined during measurement
of 1 (b))
4. Material balance confir-
mation
a. Coal input rate
b. Calorific analysis of
coal
a. Effluent volumetric flow
rate (determined in
2(a-e))
b. Ultimate analysis of
coal
c. Excess air (calculated
from 2(d))
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From Table III, it is obvious that the use of F Factors in calculating
E requires fewer measurements than are required by methodology in current
use. Because there are fewer measurements, the inaccuracies attendant to
measuring items 2 through 4 (except for 2d) are not included in the final
results. Granted that those measurements in 2 must be made for isokinetic
sampling, but the errors made do not contribute directly to the emission stan-
dard calculation.
Conclusion
It has been shown that, for a given type of fuel, a relationship exists
between the fuel heat value and dry effluent that permits a constant (F Factor)
to be calculated within +_ 3% deviation.
This implies that: (1) pollutant emissions in lb/106 Btu can be easily
calculated when only pollutant concentration, 02 concentration, and fuel type
are known, thus eliminating the need for measuring effluent volumetric flow rate
and heat input rate; (2) the inconsistencies that arise in measuring the heat
input rate are eliminated while at most a maximum error of 3% may be propagated
from the F Factor to the pollutant emission rate; and (3) if effluent volumetric
flow rate (Qs) and heat input rate (QH) are measured, an Fm Factor can be cal-
culated from those values and compared with the F Factor as a mass balance check.
In short, use of the F Factor provides a method less complex than the one
now employed for calculating power plant emission rates and evaluating the
sampling data.
-------
References
1. Duncan. L. J.. Analysis of Final State Implementation Plans -
Rules and Regulations Environmental Protection Agency, Research
Triangle Park, North Carolina 27711, Publication No. APTD-1334 (1972).
2. Federal Register, Standards of Performance for New Stationary Sources,
36:247, Part II (Dec. 23, 1971).
3. Perry, John H., ed., Chemical Engineers' Handbook, 4th ed., p. 9-3,
McGraw-Hill Book Company, N. Y. (1963).
4. North American Combustion Handbook. North American Manufacturing Co., 13,
Cleveland (1965).
5. Hodgman, Charles D., Handbook of Chemistry and Physics. 43rd ed., 1943 -
1944, Chemical Rubber Publishing Co., Cleveland (1961).
6. Analyses of Tipple and Delivered Samples of Coal, U. S. Dept. of Interior,
U.S. Bureau of Mines, Washington, D. C., Publication No. USBMRI 7588 (1972).
7. U.S. Dept. of interior, U.S. Bureau of Mines, Washington, D. C., Publica-
tion No. USBMRI 7490 (1971).
8. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D. C., Publica-
tion No. USMBRI No. 7346 (1970).
9. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D. C., Publica-
tion No. USMBRI 7219 (1969).
10. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D. C., Publica-
tion No. USMBRI 6792 (1966).
8
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References (Continued)
11. Hodgman, Carles D., ed. Handbook of Chemistry and Physics, 43rd ed.,
1936, Chemical Rubber Publishing Co., Cleveland (1961).
12. North American Combustion Handbook, North American Manufacturing Co., 31,
Cleveland (1965).
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EMISSION CORRECTION FACTOR for FOSSIL FUEL-FIRED STEAM GENERATORS
C02 CONCENTRATION APPROACH
Roy Neulicht*
Introduction
The Federal Standards of Performance for New Stationary Sources
regulating particulate matter, sulfur dioxide, and nitrogen oxide
emissions from fossil fuel-fired steam generating units of more than 63
million kcal/hr (250 million Btu/hr) heat input are expressed in terms
of mass per unit of heat input, g/106 cal (lb/106 Btu). To arrive at
this emission rate, the existing method1 requires determination of the
pollutant concentration (C), the effluent volumetric flow rate (Q ), and
the heat input rate (Qh). An F-Factor approach requiring determination
of the fuel type, pollutant concentration (C), and the oxygen concentra-
o
tion (%02) has been proposed as the reference method to replace the
existing method.
The purpose of this paper is to present a third method, based on the
F-Factor approach and employing a dilution correction factor based on
measuring the carbon dioxide rather than oxygen concentration. This method,
which will be called the Fc-Factor method,is based on two facts:
1. The comparison of the theoretical carbon dioxide produced during
combustion to the measured carbon dioxide provides an exact basis
for dilution correction.
2. Within any fossil fuel type category, the ratio of the volume of
carbon dioxide to the calories released is essentially a constant.
The method has two advantages:
1. Emission rates may be determined from wet basis concentration
measurements without recalculation of the F -Factor.
c
* Emission Measurement Branch, ESED, OAQPS, EPA, RTP, NC
Published in Stack Sampling News 2(8): 6-11, February 1975
10
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2. Use of COp for correcting for dilution provides flexibility
»
by providing an additional method for determining emission
rates; for example, in some cases measuring COp may be more
convenient than measuring CL.
One disadvantage of the C02 correction factor is that it cannot be used
after control devices that alter the COp concentration (e.g., wet scrub-
bers that remove COp) or in situations where COp is added.
Derivation of F -Factor Method
The method calculating emission rates as promulgated in the Federal
0
= C
Register is:
where: E = pollutant emission, g/106 cal (lb/106Btu)
C = pollutant concentration, dry basis, g/dscm, (Ib/dscf)
Q = dry effluent volumetric flow rate, dscm/hr (dscf/hr)
QH= heat input rate, 106 cal/hr (106 Btu/hr)
When the laws of conservation of mass and energy are applied, the following
must hold true:
vt
~ - 19 i
2t/ HHV
where: V = total theoretical dry combustion products per unit
mass of fuel burned, dscm/g (dscf/lb)
HHV= high heating value, 106 cal/g (106 Btu/lb)
11
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%co2m
= dilution correction factor, ratio of measured car-
bon dioxide and theoretical carbon dioxide produced
from combustion, dry basis
Solving Equation 2 for the ratio QS/QH and substituting into
Equation 1 yields:
E =
vc
Substituting f- (100) for %C02t yields:
L
/vt\
HHY
where: VG= theoretical volume of carbon dioxide, produced per unit
mass of fuel burned, scm/g (scf/lb)
Elimination of Vt from Equation 4 and rearrangement yields:
E = (
or
vc
where: FC= p^y , the ratio of theoretical C02 generated by
combustion to the high heating valve of the fuel com-
busted, scm/106 cal (scf/106 Btu).
The high heating value of the fuel combusted can be obtained from
12
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standard calorific determinations. The amount of theoretical carbon
dioxide generated by combustion can easily be calculated from the ulti-
mate analysis. The ratio, FC, has been calculated for various fossil
fuels from data obtained from the literature; these calculated ratios
are summarized in Table I. For any fuel type, the ratio is found to
be a constant with a maximum deviation of +_ 5.9%. Average FC - Factors
for each fuel type are given in Table II.
Note that Equation 6 for the determination of the pollutant emission
rate (E) has been developed in terms of dry measurements. However, it
is a simple matter to show that wet basis measurements may be used. Given
Equation 6 and multiplying both the measured pollutant concentration (C)
and the measured carbon dioxide concentration (%C02m) by the dry mole frac-
tion (D) of the effluent gas yields;
f 100
i1
(7)
or
F
w r
w £LU c
where: C = pollutant concentration, wet basis, g/scm (Ib/scf)
W
%C02= measured concentration of carbon dioxide, wet basis,
(expressed as percent).
Equations 6 and 8 show that, using the average F - Factor approach,
the pollutant emission rate (E) can be obtained by simply knowing the type
of fuel burned and measuring the pollutant and carbon dioxide concentrations
13
-------
,
V= 0.200 x lO'4 %C -- (9)
on either a wet or dry basis.
Determination of F - Factor
_ c _
Rather than use an average FC - Factor, the F - Factor can be de-
termined on an individual case-by-case basis. As already stated, the
high heating value of the fuel is determined from standard calorific
determinations. The theoretical carbon dioxide generated by combustion
is easily calculated from the following equations based on stoichiometry3
and on information from an ultimate fuel analysis:
scm C0
c '
or
scf CO,
V °'321 %c Tb-FUeT (10)
where: %C= percent carbon by weight determined from
ultimate analysis.
Given the definition of the F - Factor,
vc
Fc= HHV (ID
and substituting Equations 9 and 10 yields:
Fc= - am/ - for metric units of (12)
"HV scm/106 cal
and
0 321 %C
Fc= *HHV - for En9lisl1 "ni'ts of (13)
scf/ 10° Btu
Note: %C and HHV must be on a consistent basis, e.g., if %C is deter-
mined on an as-received basis, HHV must also be on an as-received basis.
14
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Conclusion
It has been shown that, for a given fuel type, a relationship
exists between the fuel calorific value and the theoretical effluent
carbon dioxide, which permits an average F - Factor to be calculated
c
within +_ 5.9% deviation. This provides a method for calculating power
plant emission rates that may be used when the pollutant concentration,
carbon dioxide concentration, and fuel type are known. The equation
for such a calculation is given as follows:
(14)
where: E = pollutant emission, g/10 cal (lb/10 Btu)
C = pollutant concentration, g/scm (Ib/scf)
%COp = carbon diox-ide content by=volume (expressed as
percent)
F = a factor representing a ratio of the volume of
theoretical carbon dioxide generated to the
calorific value of the fuel combusted.
Note: C and %C02 may be measured either on a wet or
dry basis provided that the same basis is used
for each.
Furthermore, average values of F are given for each fossil fuel
type, and the necessary equations for determining the F - Factor on a
case-by-case basis are presented.
15
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TABLE I. FC - FACTOR FOR FOSSIL FUELS
Li
Fuel Type
Coal
Anthracite
Average
Bituminous
Lignite
Average
Oil
Crude
Residium
Distillate
Average
Gas
Natural
Average
Propane
Average
Butane
Average
terature
Source
4
5
6
6
7
8
9
10
11
6
4
5
12
12
12
13
4
13
13
Number of
Samples
3
1
3
13
39
15
46
41
58
1
1
1
6
4
2
4
3
2
2
Average
scmaC02
106 cal
0.2202
0.2292
0.2218
0.2222
0.2029
0.2032
0.2065
0.2025
0.2022
0.2011
0.2105
0.2123
0.2027
0.1585
0.1591
0.1655
0.1610
0.1613
0.1160
0.1180
0.1168
0.1351
0.1351
0.1420
0.1420
Max. Dev.,%
+
4.1 4.1
5.9 5.2
5.1 2.2
3.9 2.0
1.0 1.0
1.0 1.0
Standard conditions are 70°F, 29.92 in.
Hg, and 0% excess air.
16
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TABLE II. AVERAGE FC - FACTORS
Fuel Type scma COg/106 cal scfa C02/106 Btu
Coal
Anthracite
Bituminous and lignite
Oil
Gas
Natural
Propane
Butane
0.222
0.203
0.161
0.117
0.135
0.142
1980
1810
1430
1040
1200
1260
Standard conditions are 70°F, 29.92 in. Hg, and 0% excess air.
T7
-------
REFERENCES
1. Federal Register, Standards of Performance for New Stationary
Sources, 36_:247, Part II, December 23, 1971.
2. Federal Register, Proposed Emission Monitoring and Performance
Testing Requirements for New Stationary Sources, 39_:177, Part II,
September 11, 1974.
3. North American Combustion Handbook, North America Manufacturing
Co., Cleveland, 1965, p.48.
4. Perry, John H.
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REFERENCES(Continued)
12. North American Combustion Handbook, North America Manufacturing
Co., Cleveland, 1965, p.31.
13. North American Combustion Handbook. North America Manufacturing
Co., Cleveland, 1965, p.35.
14. Shigehara, R.T. et al. "A Method for Calculating Power Plant
Emission Rates," Stack Sampling News, Volume 1, Number 1, July, 1973.
19
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DERIVATION OF EQUATIONS FOR CALCULATING POWER PLANT EMISSION RATES
02 Based Method - Wet and Dry Measurements
R. T. Shigehara & R. M. Neulicht*
INTRODUCTION
The Federal New Source Performance Standards1 regulating particulate matter,
sulfur dioxide, and nitrogen oxides emissions from fossil fuel-fired steam
generating units are expressed in terms of mass emissions per unit of heat input.
o
Shigehara et al. developed a means of determining the emission rates in the de-
sired terms using stoichiometric factors and oxygen (02) measurements. This pro-
cedure is expressed in equation form as follows:
20.9
where: E = emission rate, lb/106 Btu
C = pollutant concentration, Ib/scf
F = fuel stoichiometric factor, scf/106 Btu
%02 = 02 concentration, percent.
Initially, the above expression has been applied only to dry (moisture free)
based measurements. However, because some automatic instruments are capable of
determining carbon (C) and %02 on a wet basis, questions have been asked about the
derivation of Equation 1 and how wet based measurements affect the equation. The
derivation of the equations for wet and dry based measurements and a list of average
F-factors are presented in this text.
DERIVATION OF EQUATIONS
The basic equation for calculating emission rate is given by:
C Q,
Emission Measurement Branch, ESED, OAQPS, EPA. July 1976
20
-------
where: Qs = effluent volumetric flow rate, scf/hr
QH = heat input rate, 106 Btu/hr.
The product of C and Qg is simply the mass rate; thus, both C and QS must
be determined on a consistent basis, i.e. either wet or dry. To distinguish be
tween wet and dry based measurements, the subscripts "w" and "d", respectively,
will be used.
Dry Basis
If E is calculated from dry based measurements, Equation 2 becomes:
E - !3j!sd (3)
4H
Qsd can be written as:
Qsd = Sd + EAd
where: Sd = dry volumetric flow rate of effluent at stoichiometric condi-
tions, dscf/hr
EA. = dry volumetric flow rate of excess air in the effluent, dscf/hr.
An adjustment factor, Ad, which when multiplied by Qsd would adjust it to
dry stoichiometric conditions, Sd, can be derived as follows:
Qsd Ad ' Sd ' ^sd - EAd
Since EAd = QQ /0.209, where QQ is the volumetric flow rate of 02 in the
effluent and 0.209 is the fraction by volume of 02 in dry air,
21
-------
A =
d " 0.209
Noting that QQ /Q d is the proportion by volume of 02 in the dry effluent mix-
ture (02Dd) and Substitutin9 into Equation 7, Ad becomes:
Ad = ] " 0.209
20.9 - %09.
30.9 (8)
20.9 - %02d
and Sd = Qsd ( 2Q^ *°) (9)
Substituting Equation 9 into Equation 2 yields:
F = r ?d 20.9 nm
- Cd QH 20.9 - %02d * '
The ratio, Sd/QH, is simply the dry effluent gas at stoichiometric conditions
generated per unit of heat input and can be calculated from ultimate and calori-
fic analyses of the fuel. These calculated ratios are defined as Frf and are
summarized in Table I. Inserting Fd = Sd/QH>
Equation 10 can be rewritten in its final form as:
L, "~ w i r i OYY~ ft mQ?r^ \ * * /
a d 20.9 - %0nj
22
-------
Met Basis
If E is calculated from wet based measurements, Equation 2 becomes:
(12)
As before, Q can be written as:
sw
If the combustion air is dry, then EA = EA. and S,., and Q, will only
W Q W SW
include moisture derived from the fuel. It follows that:
Sw ' QSW - EAd
EAH
-Q-^
ysw
0.209
(16)
°2PW
1.20
20.9 - %0
2
20.9
20.9 -
Sw = Qsw209
23
-------
20.9
w QH 20.9 -
Defining SW/QH as FW,
= P F
L h
w w 20.9 -
To assume that combustion air is dry, however, is obviously not true.
EA must include moisture so that:
EAH
^ (22)
where B is the moisture content in the ambient air; the subscript "a" is
Wot
used to denote the inclusion of ambient moisture. Note also that Q and S
now include the moisture from the ambient air. Following steps that are similar
to steps 14 through 21:
= Qswa ' EAwa
(24)
(25)
Q - (1-B )
v v wa '
Q02
0.209
24
-------
n
0.209 (1 - B
( '
20.9 (1 - B)
20.9
Q
swa - 20.9 (1 - B
E-f $wa 20'9 (1 - Bwa) , ,
(30)
Defining S /QH as Flia:
wo n WQ
20-9 (1 - B )
r
F
uia
via
wa wa 20.9
The inclusion of ambient air in Fwa, however, is undesirable in that it
becomes a variable. Written in terms of F , i.e. where ambient moisture is not
W
included, F can be written as:
Wa
s + ThA ' V
F -5wa- H T1~r^J
Fwa - QH (^ - (32)
25
-------
Jw . ThA
wa
1 - B.
wa
(33)
where ThA is the theoretical air required for complete combustion. Defining,
as before, SW/QH as FW> i.e. without ambient air moisture, and ThA/QH as FThA
i.e. theoretical air per unit of heat input, Equation 33 can be rewritten as:
Fwa " Fw
ThA
wa
1 - B.
wa
(34)
= F.
w
FThA ( Bwa
Fw V1 - Bwa
(35)
Substituting into Equation 31 and simplifying yields:
E Cwa F«
wa w
1 - B
ThA
w
(^
( "« VI
0 - *J\
20.9 (1
-Bwa>
20.9 (1 - B } - 5>0~
20.9
wa
1.9
(36)
Consider now the expression [1 - Bwa (1 - FThA/Fw)"j. Average values of
FThA/Fw are: coal = 0.960; oil = 0.948; gas = 0.914. An extreme case of ambient
moisture content of 6.4% would occur at 100°F and 100% relative humidity. The ex-
pression cited above under these conditions would yield values of: coal = 0.9975;
26
-------
oil = 0.9967; and gas = 0.9945. Therefore, neglecting this cited expression
would introduce a positive bias of no more than o.25 to 0.55%. Understanding
this, Equation 36 simplifies to its final form:*
= r p 20.9
wa w *°-9 <* - Bwa) - %02wa
Average values of FW are listed in Table II. From Tables I and II it can
be seen that Fd factors have a maximum arithmetic deviation of ± 3.1 percent
and FW factors, +3.8 percent.
REFERENCES
1. Standards of Performance for New Stationary Sources. Federal Register.
(Washington) Part II. 36:247, December 23, 1971.
2. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. A Method for Calculating
Power Plant Emission Rates, Stack Sampling News. L5-9, July 1973.
* This equation was originally derived by G. F. McGowan, Vice President,
Environmental Technology Division, Lear Siegler, Englewood, Colorado.
27
-------
Table I. AVERAGE Fd FACTORS FOR FOSSIL FUELS
Fuel type
Coal
Anthracite
Bituminous, lignite
Oil
Nat. gas, propane, butane
Samples,
No.
4
229
16
9
hd
dscf/106 Btua
10140
9820
9220
8740
Max. dev.,
%
±2.0
±3.1
±3.0
+ 2.2
Standard conditions are 70CF, 29.92 in. Hg, and 0% excess
air.
Table II. AVERAGE F FACTORS FOR FOSSIL FUELS
w
Fuel type
Coal
Anthracite
Bituminous
Lignite
Oil
Gas
Natural
Propane
Butane
Samples,
No.
7
129
174
13
7
2
2
wscf/106 Btua
10580
10680
12000
10360
10650
10240
10430
Max. dev.,
%
±1.5
±2.7
±3.8
±3.5
±0.8
+0.4
±0.7
Standard conditions are 70 °F, 29.92 in. Hg, and 0% excess air.
28
-------
SUMMARY OF F FACTOR METHODS FOR DETERMINING
EMISSIONS FROM COMBUSTION SOURCES
R. T. Shigehara, R. M. Neulicht, W. S. Smith,
and J. W. Peeler
INTRODUCTION
The Federal Standards of Performance for New Stationary Sources, regulating
particulate matter, sulfur dioxide, and nitrogen oxide emissions from fossil
fuel-fired steam generating units, are expressed in terms of pollutant mass per
unit of heat input. Many State regulations for combustion equipment are ex-
pressed in the same form. To arrive at this emission rate, the original method1
required the determination of the pollutant concentration, effluent volumetric
flow rate, and heat input rate. In the October 6, 1975, Federal Register,2 an
"F Factor" technique, which required only the determination of the fuel type,
pollutant concentration, and the oxygen (02) concentration, was promulgated as
a procedure to replace the original method. At the same time, an F Factor approach,
based on either 02 or carbon dioxide (C02) measurements, was promulgated for use
in reducing the pollutant concentration data obtained under the continuous monitor-
ing requirements to the desired units. Recently, wet F Factors,3 which allow the
use of wet basis measurements of the same parameters, and F Factors for wood and
refuse have been calculated.
The purpose of this paper is to summarize the various methods and to present
the calculated F Factor values for the different types of fuels. The various
uses of F Factors and errors involved in certain applications and conditions are
also discussed.
SUMMARY OF METHODS
The first method, referred to simply as the F Factor Method, is based on two
principles:
Published in Source Evaluation Society Newsletter 1(4), November 1976
29
-------
1. The ratio of the quantity of dry effluent gas generated fay combustion
to the gross calorific value of the fuel is a constant within any
given fuel category. This ratio is normally called the dry F Factor;
however, for purposes of this paper, it will be called the Fd Factor.
2. An excess air correction factor may be expressed in terms of the dry
oxygen content of the effluent stream.
The use of this method requires dry basis measurements of the pollutant concen-
tration (Cd) and percent oxygen (%02d). The emission rate (E) is calculated by
the equation:
r p F f 20-9
fc " d d \20.9 - %00
\ £u
If the moisture content of the flue gas (Bws) is determined, a natural
derivative of Equation 1, which would allow direct wet basis measurements of
pollutant and oxygen concentrations, i.e. GW and %02w> respectively, is as follows
E ' Cw Fd
20.9
(2)
This equation has been approved in principle by the Environmental Protection
Agency and may be used if it is demonstrated that BWS can be accurately determined
and that any absolute error in B^. will not cause an error of more than +_ 1.5
Wo
percent in the term £0 9
20.9 (i - BWS; - *u2w
The second technique, called the F Factor Method, is based on the same two
W
principles as the Fd Factor Method, except that the two quantities, the effluent
gas and the oxygen concentration, are determined on a wet basis. The ratio of
30
-------
the quantity of wet effluent gas generated by combustion to the gross calorific
value of the fuel is called the wet F Factor or the F Factor. The use of this
w
technique, however, requires in addition to the wet pollutant concentration (C )
W
and oxygen (%02w) the determination of the fractional moisture content of the
air (Bwa^ suPP11ed for combustion. (Guidelines for this determination will be
discussed later.) The equation for calculating the emission rate is:
E - Cw Fw
20.9
H -
(3)
This equation is a simplification of the theoretically derived equation.3 Under
typical conditions, a positive bias of no more than 0.25 percent is introduced.
The third procedure, the FC Factor Method, is based on principles related
to but slightly different than those for the Fd Factor and F Factor Methods:
1. For any given fuel category, a constant ratio exists between the volume
of carbon dioxide produced by combustion and the heat content of the
fuel. This ratio is called the FC Factor.
2. The ratio of the theoretical carbon dioxide produced during combustion
and the measured carbon dioxide provides an exact basis for dilution
correction.
This method requires measurement of the pollutant concentration and percent car-
bon dioxide (%C02) in the effluent stream. Measurements may be made on a wet or
dry basis. Using the subscripts, "d" and "w", to denote dry and wet basis mea-
surements, respectively, the equations for calculating E are:
31
-------
DETERMINATION OF F FACTORS
6 6 6
Values of Frf in dscf/10° Btu, FW in wscf/10b Btu, and FC in scf/106 Btu,
may be determined on an individual case-by-case basis using the ultimate
analysis and gross calorific value of the fuel. The equations are:
c = IP6 (3.64 XH + 1.53 XC + 0.57 XS + 0.14 XN - 0.46 XO)
d GCV
= IP6 (5.57 XH + 1.53 XC + 0.57 XS + 0.14 XN - 0.46 XO + 0.21 %H20*)
w ~ - =*«
F = IP6 (0.321
c GCV
where: H, C, S, N, 0, and H^Q are the concentrations by weight (expressed in
percent) of hydrogen, carbon, sulfur, nitrogen, oxygen, and water from the ulti-
*
mate analysis. ( Note: The %H20 term may be omitted if %H and %0 include the
unavailable hydrogen and oxygen in the form of H20.) GCV is the gross calorific
value in Btu/lb of the fuel and must always be the value consistent with or
corresponding to the ultimate analysis.
For determining FW> the ultimate analysis and GCVW must be on an "as received"
or "as fired" basis, i.e., it must include the free water. Often in practice,
the ultimate analysis and/or gross calorific value of a particular fuel are not
known. For most commonly used fuels, tabulated average F Factors may be used in-
stead of the individually determined values. These average values of F., F , and
FC, calculated from data obtained from the literature, are given in Table I.
F Factors for wood and bark are also listed in Table I, and factors for various
types of refuse are listed in Table II.
32
-------
ULTIMATE CARBON DIOXIDE
The ratio of FC to Fd times TOO yields the ultimate percent COp or the
maximum C02 concentration that the dry flue gas is able to attain. By dividing
this number into 20.9, a ratio called the F Factor is obtained. F values cal-
o o
culated from the ultimate analyses of the various fuels are given in Tables I and
II.
FQ values can also be calculated from C02 and 02 data obtained in the field
by using the following equation.
20.9 - %0
Fo =
These calculated FQ values can be used to check Orsat data or other analyses of
C02 and 02 that have been adjusted to a dry basis. The process simply involves
comparing FQ values calculated from Equation 8 with the values listed in Table I
or II. Further details of this validation procedure are outlined in Reference 15.
ERRORS AND APPLICATION
The derivations of Equations 1 through 4 are discussed in References 3, 4,
and 5. The following discussion gives further explanation of the F Factors and
describes some of the problems and errors that arise in applying the F Factor
Methods. Several uses for F Factors in addition to calculating emission rates are
outlined.
Deviation in F Factors
The F Factors were calculated from data obtained from the literature. In
p
the October 6, 1975, Federal Register. the values of F. and F were calculated
by summing all data points and dividing by the total number of samples. Then the
deviations from the extreme values (highest and lowest) were determined. The
33
-------
higher of the two values, termed "maximum percent deviation from the average
F Factors," are listed in parenthesis in Table I. These deviations are pro-
bably due to differences in the composition of the fuel, and may also include
variations due to the analytical methods and analysts (laboratories). The stan-
dard deviations of the samples were not calculated since much of the data were
already averages of several samples and there may have been more samples from
one locale or of one kind than another.
After publication of the Fd and FC Factors, it was determined that the mid-
point value would be a better value than the average for small samples and for
data taken from the literature. Therefore, the F Factors and the values for wood
w
and refuse are midpoint values rather than arithmetic averages. The associated
deviations are termed, "maximum percent deviation from the midpoint F Factor."
F Factors for refuse, wood, and wood bark were not calculated because of the
W
high variability of free moisture contents. For example, the moisture in bark
may vary from 20 percent (air dried) to 75 percent (hydraulic debarking). Free
moisture content variations of +_ 15 percent introduce about 5 percent variation .
However, for lignite, the moisture contents vary only from about 33 to 45 percent.
This range causes a deviation of 3.8 percent from the midpoint F Factor, which
W
enabled an F Factor to be established.
W
Incomplete Combustion
The assumption of complete combustion is made in the derivation of all
F Factor Methods. If products of incomplete combustion, such as carbon monoxide,
are present in the effluent stream, the volume of effluent gas and carbon dioxide
per pound of fuel burned will differ from the values used in calculating the
F Factors. However, adjustments to the measured C02 or 02 concentration can be
made, which would minimize the magnitude of the error when applying Equations 1-5.
34
-------
These adjustments are given by the following equations:
. = %C02 + %CO (9)
= %02 - 0.5 %CO (10)
By making these adjustments, the error amounts to minus one-half the concen-
tration of CO present. Thus, if 1 percent CO (an extreme case) is present, an
error of minus 0.5 percent is introduced. Without adjusting the C02 or 02 con-
centration, a combustion source having 11 percent C02, 1 percent CO, and 6 per-
cent 0? will result in about plus 9 percent error for the F Factor Method and
£ C
about plus 3 percent for the Fd Factor and FW Factor Methods.
Similarly, unburned combustible matter in the ash will cause the volume of
effluent gas and carbon dioxide per unit of heat input to differ from the calculated
F Factor values. This is true, however, only if the heat input is thought of in
terms of the coal input rate times the calorific value. If the heat input rate is
considered as only that calorific value which is derived from the combusted mat-
ter, the F Factor Methods are only slightly affected. In other words, if any por-
tion of the fuel goes through the combustion process unburned, the F Factor Methods
will not include as heat input the calorific value associated with the uncombusted
matter, and a slight positive bias will be introduced.
The positive bias is due to the combustion process, which is said to consist
first of evaporating the free moisture, then the burning of the volatile matter,
and last the burning of the fixed carbon, with the ash remaining. The volatile
matter includes hydrogen, which results in a lower F Factor than the calculated
values. Since a higher proportion of fixed carbon than volatile matter generally
remains in the ash, the FC Factor Method is affected more than the F. Factor and
35
-------
FW Factor Methods. For example, assume that 100 Ib of a coal, which has
55 8% C, 5.7% H, 1.1% N, 3.2% S, 21.5% 0, and 12.6% ash (percent by weight, as
received basis), is burned and 5 Ib fixed carbon remains in the ash. About plus
2.3 percent error is incurred with the Fr Factor and less than 1 percent with the
C
Fd Factor and FW Factor Methods.
Effect of Wet Scrubbers
When wet scrubbers are used, a portion of the carbon dioxide may be absorbed
by the scrubbing solution. Therefore, the FC Factor Method will yield an emission
rate higher than the actual rate. If a gas stream having 14% C02 before the
scrubber loses 10 percent of the C02> or 1.4% C02, the error is about plus 13 per-
cent.
The Fd Factor Method is also affected by the loss of C02 in the scrubber,
but to a lesser degree than the FC Factor Method. If the gas stream has 6% 02 and
1.4% C02 is lost in the scrubber,!the error will be about plus 2 percent.
The FW Factor Method is not applicable after wet scrubbers since the scrubber
generally adds moisture to the flue gas, thereby "diluting" the gas stream. The
pollutant concentration will be lowered by the same proportion of moisture added
and the 02 concentration will be lower than actual, which would tend to yield lower
than true numbers.
When the scrubbing solution is lime or limestone, the F Factor Method may be
used after wet scrubbers. It is generally assumed that due to the optimum operating
conditions, the amount of C02 absorption is minimized and, therefore, the applica-
tion of the FC Factor Method will not yield appreciable errors. However, with
limestone scrubbers, there is a possibility of C02 being added to the gas stream
due to the reaction of S02 with the limestone. Therefore, the F Factors must be
increased by 1 percent.
36
-------
Determination of Ambient Air Moisture
Guidelines have been developed for the determination of B , the moisture
fraction in ambient air, in Equation 3, which will soon be published in the
Federal Register. The guidelines are presented below.
Approval may be given for determination of B by on-site instrumental mea-
Wo
surement provided that the absolute accuracy of the measurement technique can be
demonstrated to be within +_ 0.7 percent water vapor. In lieu of actual measure-
ment, Blia may be estimated as follows: (Note that the following estimating fac-
wa
tors are selected to assure that any negative error introduced in the emissions
20 9
by the estimating term 9n Q /, n \ - 57; - will not be larger than -1.5
^u>y u " bwa; "
percent. However, positive errors, or over-estimation of emissions, of as much
as 5 percent may be introduced depending upon the geographic location of the
facility and the associated range of ambient moisture.)
1. B = 0.027. This factor may be used as a constant value at any location.
Wa
2. B = highest monthly average of B,,, that occurred within a calendar year
wa wa
at the nearest Weather Service Station, calculated using data for the
past 3 years. This factor may be used on an annual basis at any facility.
3- B,,a = highest daily average of B,,, that occurred within a calendar month
Wa Wa
at the nearest Weather Service Station, calculated for each month for the
past 3 years used as an estimating factor for the respective calendar
month.
Sampling Location and Sampling Points
Ambient air leakage into an exhaust system may cause variations across the
duct or stack in the relative concentrations of COp and Op. For this reason, the
2
Federal regulations specify that COp or Op be measured simultaneously and approxi-
mately at the same point as the gaseous pollutants measurements.
37
-------
For particulate emission performance tests, which require traversing, it
is specified that the 02 samples be obtained simultaneously by traversing the
duct at the same sampling location used for each run of the Method 5. This re-
quirement may be satisfied by attaching a stainless steel tube to the particulate
sampling probe and, using a small diaphragm pump, obtaining an integrated gas sam-
ple over the duration of the run (of Reference 1). The sample should be analyzed
using an Orsat apparatus.
As an alternative to traversing the same sampling points of Method 5, a mini-
mum of 12 oxygen sampling points may be used for each run. This would require a
separate integrated gas sampling train traversing the duct work simultaneously
with the particulate run.
Other Applications
In addition to calculating emission rates, F Factors have several other uses.
If Q ^j the dry effluent volumetric flow rate, or Q , the wet effluent volumetric
flow rate, and QM, the heat input rate, are measured, a value of F ., F , or F
ri u W C
may be calculated. These equations are given below:
Qsd 20.9 - %02
Fd(calc) = 6 2O (11)
Qcu) 20.9 (1 - B) - %Q~
Msw wa' Zw
_ _ _ _
w(calc) Q^j 2079
F _Qsd *C02d_<>sw *C02w
*"c(calc) ~ 0^~ 100 " Qjj TOO"
The calculated values may then be compared to tabulated values of the F Factors
to facilitate a material balance check.
38
-------
If desired, QH can be calculated by using the Equations 11 through 13.
In the past, it has been observed that the measurement of Q has been signifi-
cantly greater than the stoichiometric calculations rates. The discrepancy is
usually due to errors in determining Qs- Due to aerodynamic interferences and
improper alignment of the pi tot tubes, higher than real readings have been ob-
tained. Therefore, errors in measuring Qg are positive, which leads to higher
than true firing rates.
If an ultimate analysis and calorific determination of a particular fuel
are made and the F Factor value is calculated, the accuracy of the results may be
checked by comparison with the tabulated F Factors.
SUMMARY
The various F Factor Methods have been summarized and calculated F Factors
for fossil fuels, wood, wood bark, and refuse material have been presented. In
addition, some of the problems and errors that arise in applying the F Factor
Method for calculating power plant emission rates were discussed and other uses
of the F Factors were outlined.
39
-------
TABLE I. F FACTORS FOR VARIOUS FUELS2"14'a'b»c
w
Fuel Type
Coal
Anthracite
Bituminous
Lignite
dscf/10° Btu
10140 (2.0)
9820 (3.1)
9900 (2.2)
wscf/10° Btu
10580 (1.5)*
10680 (2.7)
12000 (3.8)
scf/10° Btu
1980 (4.1)
1810 (5.9)
1920 (4.6)
Fo
1.070 (2.9)
1.140 (4.5)
1.076 (2.8)
Oil
9220 (3.0)
10360 (3.5)
1430 (5.1) 1.346 (4.1)
Gas
Natural
Propane
Butane
Wood
Wood Bark
8740 (2.2)
8740 (2.2)
8740 (2.2)
ic
9280 (1.9)
9640 (4.n
10650 (0.8)
10240 (0.4)
10430 (0.7)
1040 (3.9)
1200 (1.0)*
1260 (1.0)
1840 (5.0)
1Q£D (1 £\
1.749 (2.9)
1.510 (1.2)*
1.479 (0.9)
1.050 (3.4)
1 ftKA It Q}
Numbers in parenthesis are maximum deviations (%) from either the midpoint or average
F Factors.
To convert to metric system, multiply the above values by 1.123 x 10"4 to obtain
scm/10° cal.
All numbers below the asterisk (*) in.each column are midpoint values. All others
are averages.
40
-------
TABLE II. MIDPOINT F FACTORS FOR REFUSE2"14'9'b
Paper and Wood Wastes
Lawn and Garden Wastes
Plastics
Polyethylene
Polystyrene
Polyurethane
Polyvinyl chloride
Garbage6
Miscellaneous
Citrus rinds and seeds
Meat scraps, cooked
Fried fats
Leather shoe
Heel and sole composition
Vacuum cleaner catch
Textiles
Waxed milk cartons
dscf/10°Btu
9260 (3.6)
9590 (5.0)
9173
9860
10010
9120
9640 (4.0)
9370
9210
8939
9530
9480
9490
9354
9413
wscf/10°Btu
1870 (3.3)
1840 (3.0)
1380
1700
1810
1480
1790 (7.9)
1920
1540
1430
1720
1550
1700
1840
1620
ro
1.046
1.088
1.394
1.213
1.157
1.286
1.110
1.020
1.252
1.310
1.156
1.279
1.170
1.060
1.040
(4.6)
(2.4)
(5.6)
a Numbers in parentheses are maximum deviations (%) from the midpoint F Factors.
b -4
To convert to metric system, multiply the above values by 1.123 x 10 to obtain
scm/10 cal.
c Includes newspapers, brown paper, corrugated boxes, magazines, junk mail, wood,
green logs, rotten timber.
Includes evergreen shrub cuttings, flowing garden plants, leaves, grass.
e Includes vegetable food wastes, garbage (not described).
41
-------
REFERENCES
1. Standards of Performance for New Stationary Sources. Federal Register.
36.:247, Part II. December 23, 1971.
2. Requirements for Submittal of Implementation Plans and Standards for New
Stationary Sources. Federal Register. 40_:194, Part V. October 6, 1975.
3. Shigehara, R. T. and R. M. Neulicht. Derivation of Equations for Calculating
Power Plant Emission Rates, (L Based Method - Wet and Dry Measurements. Emis-
sion Measurement Branch, ESED, OAQPS, U. S. Environmental Protection
Agency, Research Triangle Park, N.C. July 1976.
4. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. A Method for Calculating
Power Plant Emissions. Stack Sampling News. 1_ (l):5-9. July 1973.
5. Neulicht, R. M. Emission Correction Factor for Fossil Fuel-Fired Steam Genera-
tors: C02 Concentration Approach. Stack Sampling News. 2^ (8);6-ll. February 1975.
6. Fuels, Distribution, and Air Supply. In: C-E Bark Burning Boilers (Sales
Brochure). Windsor, Conn., Combustion Engineering Inc. p.5.
7. Kaiser, E. R. Chemical Analyses of Refuse Components. In: Proceedings of 1966
National Incinerator Conference. The American Society of Mechanical Engineers,
1966. p.84-88.
8. Kaiser, E. R., C. D. Zeit, and J. B. McCaffery. Municipal Refuse and Residue.
In: Proceedings of 1968 National Incinerator Conference. The American Society
of Mechanical Engineers, 1968. p.142-152.
9. Kaiser, E. R. and A. A. Carrotti. Municipal Refuse with 2% and 4% Addition of
Four Plastics: Polyethylene, Polyurethane, Polystyrene, and Polyvinyl Chloride.
In: Proceedings of 1972 National Incinerator Conference. The American Society
of Mechanical Engineers, 1972. p.230-244.
42
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10. Kaiser, E. R. The Incineration of Bulky Refuse. In: Proceedings of 1966
National Incinerator Conference. The American Society of Mechanical Engineers,
1966. p.39-48.
11. Newman, L. L. and W. H. Ode. Peat, Wood, and Miscellaneous Solid Fuels. In:
Mark's Standard Handbook for Mechanical Engineers, Baumeister, T. (ed.).
7th ed. New York, McGraw-Hill Book Company, 1967. Chapter 7, p.19.
12. MacKnight, R. J. and J. E. Williamson. Incineration: General Refuse Incinera-
tors. In: Air Pollution Engineering Manual, Danielson, J. A. (ed.). 2nd ed.
OAWM, OAQPS, U. S. Environmental Protection Agency, Research Triangle Park,
N. C. AP-40. May 1973. p.446.
13. Steam, Its Generation and Use. 37th ed. New York, the Babcock and Wilcox
Company, 1963. Appendix 3-A4.
14. The Ralph M. Parsons Company. Solid Waste Disposal System, Chicago. Vol. II
Study Report Appendices. Prepared for Bureau of Engineering, Department of
Public Works, City of Chicago. May 1973.
15. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. Validating Orsat Analysis
Data from Fossil Fuel-Fired Units. Emission Measurement Branch, ESED, OAQPS,
U. S. Environmental Protection Agency, Research Triangle Park, N. C. June 1975.
43
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VALIDATING ORSAT ANALYSIS DATA FROM FOSSIL-FUEL-FIRED UNITS
R. T. Shigehara, R. M. Neulicht, and W. S. Smith
INTRODUCTION
In the September 11, 1974 Federal Register.1 a new reference method
for calculating the pollutant emissions from fossil fuel-fired steam -
generating units of more than 250 million Btu/hr heat input was proposed.
This proposed method is based on the law of conservation of mass and energy
and utilizes oxygen (02) concentration to compensate for excess or dilution
air. Recently, another method has been published3 that uses the same prin-
ciple, except that carbon dioxide (C02) concentration is used to adjust for
excess or dilution air.
The validity of both methods relies heavily on the accuracy of either
the 02 or C02 measurement. Therefore, it is desirable to have some criteria
for validating the data as soon as they are obtained in the field. Since,
in many cases, both 02 and C02 measurements are obtained from Orsat analyses,
guidelines are given for validating the data from these analyses.
C02-02 RELATIONSHIP
Since air is used for the combustion process, the law of conservation
of mass demands that:
%Q2 + FQ %C02 = 20.9 (1)
where: %02 = 02 content by volume (expressed as percent), dry basis
%C02 = C02 content by volume (expressed as percent), dry basis
FQ = fuel factor; depends on the type of fuel burned
20.9 = 02 content in air by volume (expressed as percent), dry basis.
Published in Stack Samnlinr Mews 1(2): 21-2r, Aunust l°7fi.
44
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Solving for F , we obtain:
20.9 - %09
Fo ' %C0
The factor F is mainly a function of the hydrogen (H) to carbon (C) ratio
in the fuel. At zero percent excess air (i.e., when fuel is burned com-
pletely with stoichiometric amount of air), Equation 2 simplifies to:
20.9
F =
<%CVult
where (^Mult is the ultimate C02 or the maximum C02 concentration that
the dry flue gas is able to attain. Given the ultimate analysis of the fuel
being burned, this value can be calculated by using the following equation:
UCO ) = _ 0-321 K (100) _____ ,4)
^Vult 1.53 %C + 3.64 %H + 0.57 %S + 0.14 %N - 0.46 %0 ^'
where %C, %H, %S, %N, and %0 are the percent by weight of carbon, hydrogen,
sulfur, nitrogen, and oxygen, respectively, obtained from the ultimate
analysis .
Equations 1 through 4 can be used to check Orsat data or other analyses
of C02 and Op that have been adjusted to a dry basis. The process simply in-
volves comparing F values calculated from Orsat analyses (Equation 2) with
F values calculated from the ultimate analyses of the fuels being burned
(Equations 3 and 4). Alternatively, a graphical approach may be used. With
C02 as the abscissa and 02 as the ordinate on arithmetic paper (see Figure 1),
a straight line drawn between 20.9% 02 and the ultimate C02 calculated from
the ultimate analysis (Equation 4) represents Equation 1. The Orsat analysis
45
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8 10 12
C02 (DRY), percent
Figure 1. Graph construction for checking Orsat data.
46
14 16 18 20
-------
is checked by plotting the data points on this graph.
Equation 1 or 2 assumes complete combustion of the fuel. If carbon
monoxide (CO) is present in measurable quantities, the (L and C02 must be
adjusted when using the equations as follows:
= %C02 + %CO (5)
= %02 - 0.5 %CO (6)
Since the method of validating Orsat analyses is based on combustion
of fossil fuel and dilution of the gas stream with air, this method will not
be applicable to sources that (1) remove C02 (e.g., sources that use wet
scrubbers) or 02> or (2) add 02 and N2 in a proportion different from that
of air or (3) add C02 (e.g., cement kilns).
SUMMARY OF AVERAGE FQ FACTORS AND ULTIMATE C02'S
When ultimate analyses of the fuel being burned are not available,
averages may be used. Table I summarizes F factors and ultimate C02's and
their averages for various type fuels based on ultimate analyses reported in
the literature. " Some of the average F factors and (%C02) ,. were cal-
culated by use of a small number of samples. It is recommended, therefore,
that the data be updated by users as more information becomes available. The
manner in which these averages can be used to validate Orsat data will be ex-
plained later.
FQ and ULTIMATE C02 TOLERANCES
As mentioned earlier, the purpose for the 02 or CXL measurements is
primarily to adjust the pollutant concentrations for dilution air. In
47
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Table I FQ Factors for Fossil Fuels3
Literature
Fuel type source
Number of Average
samples F0
rn *
LU;
2ult
Maximum Deviation, %
Coal
Anthracite
Overall avg.
Bituminous
Overall avg.
Lignite
Overall avg.
Oil
Crude
Residium
Distillate
Overall avg.
Gas
Natural
Overall avg.
Propane
Overall avg.
Butane
Overall avg.
6
7
8
8
9
10
11
12
8
6
16
7
14
14
14
15
6
15
15
3
1
3
13
38
13
39
26
1
1
198
1
6
4
2
4
3
2
2
1.0786
1.0525
1.0671
1.0699
1.1202
1.1407
1.1336
1.1450
1.1435
1.1398
1.0779
1.0791
1.0761
1.0761
1.3628
1.3561
1.3280
1.3464
1.3465
1.7594
1.7349
1.7489
1.5095
1.5095
1.4791
1.4791
19.38
19.86
19.59
19.53
18.66
18.32
18.44
18.25
18.28
18.34
19.39
19.37
19.42
19.42
15.34
15.41
15.74
15.52
15.52
11.88
12.05
11.95
13.85
13.85
14.13
14.13
2.9 2.3
3.6 4.5
2.8 2.8
2.9 4.1
1.8 2.9
1.2 1.2
0.9 0.9
a _. . ...
70°F, 29.92 in. Hg, and 0% excess air.
48
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evaluating the effect of the inaccuracy of the measurement on the final
result, it is important to consider not only the 02 and C02 relationship,
but also the level of their concentrations. An explanation follows.
The adjustment factors for dilution air are:
20.9 - KQ
=
'do 20.9 - %02
KC
Fdc = ICO^ (8)
where: FdQ and Fd = adjustment factors for dilution air based on Op and
C02> respectively
KQ and K = reference 02 and C02 concentrations, respectively
%02 and %C02 = percent by volume of 02 and COp, respectively, dry basis
20.9 = percent by volume of 02 in air, dry basis.
The relative errors introduced in the adjustment factors by inaccuracies
of the 02 and C02 measurement can be approximated by the following equations
(also shown graphically in Figure 2):
do 20.9 -
d(25C09)
Edc = --
where: Edo and E. = relative errors introduced in the adjustment factors
based on Op and CO^, respectively, percent
49
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0 2 4 6 8 10 12
LEVEL OF C02 OR 02, percent
Figure 2. Relative errors resulting from inaccurate CO2 or C>2 measurements.
50
16 18
-------
d(%02) and d(%C02) = deviation from the true value of 02 and C02, respec-
tively, percent by volume.
If d(%02)'s and d(%C02)'s can be determined or estimated, Figure 2
can be valuable in making decisions or evaluations. For example, if the
C02 level is about 12 to 14%, Fyrites* that are capable of measuring C02 to
within 0.5% would be adequate for making Fdc calculations. If the C02 con-
centration is down at the 2% level, however, it can be seen that to achieve,
for example, a 5% accuracy, a measurement to within 0.1% C02 is required.
Thus, Orsats With burettes capable of measuring to within 0.1% C02, not
Fyrites, should be used.
To estimate the tolerances of FQ and the ultimate C02 for a desired
accuracy of Ed(J or Edc> the following relationship is helpful:
(11)
Equation 11 shows that the tolerance of FQ or (%C02) lt is the sum of
Edo and Edc' With the understanding that Edo and Ed can be a range of plus
or minus values, however, the tolerance of FQ or (%C02)ult must be limited to
the same magnitude of Edo or Edc to ensure that EdQ or Edc will be less than
that magnitude. For example, to limit Ed(J or Edc to +_ 5%, F or (%COJ
must also be limited to + 5%.
PROCEDURE
Based on the previous discussion, the following procedure can be
established for validating Orsat analysis data:
dFo
Fo
d(%co2)ult
(%co2)ult
d(X02)
20.9 - %02
d(%C02)
%co2
= -
100
* Trade name; not to be considered an endorsement.
51
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1 . Decide tolerances for E. or E. .
2. If ultimate analysis of fuel being burned is available, calculate
FQ using Equations 3 and 4 or (*C°2^ult using Equation 4. Otherwise, use
average values from Table I. Then calculate the limits of tolerance for
FQ or (^C02^ulf For examPle> lf a - 5% tolerance is desired, the tolerance
limits would be 0.95 and 1.05 times the calculated F, or (% COp) ult. Con-
struct graphs as in Figure 1, using these tolerance limits.
3. To compare field Orsat data, calculate FQ, using Equation 2, or
plot the data points on the graph. Values beyond the established tolerance
levels should be rejected and the analysis run over.
If average values, rather than the ultimate analysis of the fuel being
burned, serve as the basis of comparison, it should be understood that there
may be exceptions. If repeated Orsat analyses, including a double-check of
the Orsat apparatus and analyses run by another person, consistently yield
values that are rejected, the average values should be considered suspect
and the Orsat analyses accepted.
A graphical nomograph technique using a +_ 5% tolerance level and average
values from Table I is shown in Figure 3.
SUMMARY
For any given fuel burned with air, a relationship between 02 and C02
must exist. This relationship can be used to advantage to validate Orsat
analysis data. On the basis of ultimate analysis or average values of F or
(%C02) lt calculated from data in the literature, a procedure has been pre-
sented for validating Orsat analysis data.
52
-------
21E £t
20 :
19 :
1 R
17
16
15
14
12
i
s. n
^
K
s 10
CM
O
8
7
6
5
4
3
2
~^~~
I ~
\
~ __
£1
20
19
18
"
E_ -|«
^
E_ -|
\- -i
^ ^
= v -1
E Vvx ANTHRACITE. LIGNITE -
- ^tfx
vv
= BITUMINOUS '^Vv OIL -
E~ ^b^ BUTANE =
^^OC "^URAL GAS
E- \ -E
E =
^^~>
r z
- ^
^^^
= ~
-
__ -
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
r 3.
Figure 3. Nomograph for checking Orsat data ± 5% in Edo or
53
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REFERENCES
1. Federal Register, Proposed Emission Monitoring and Performance
Testing Requirements for New Stationary Sources, 39:177, Part II
(September 11, 1974).
2. Shigehara, R. T., Neulicht, R. M., and Smith, W. S., "A Method
for Calculating Power Plant Emission Rates," Stack Sampling News, July,
1973, Volume 1, Number 1, p. 5-9.
3. Neulicht, R. M., "Emission Correction Factor for Fossil Fuel-
Fired Steam Generators: C02 Concentration Approach," Stack Sampling News,
February, 1975, Volume 2, Number 8, p. 6-11.
4. DeVorken, H., Chass, R. L., and Fudurich, A. P., "Air Pollution
Source Testing Manual," APCD, County of Los Angeles (1972), p. 96.
5. North American Combustion Handbook, North American Manufacturing
Company, Cleveland (1965), p. 48.
6. Perry, John H., ed., Chemical Engineers' Handbook, 4th ed., McGraw
Hill Book Company, N. Y. (1963), p. 9-3.
7. North American Combustion Handbook, North American Manufacturing
Company, Cleveland (1965), p. 13.
8. Steam, The Babcox and Mil cox Company, New York (1963), p. 2-10.
9. Analysis of Tipple and Delivered Samples of Coal, U. S. Dept. of
Int., U. S. Bureau of Mines, Washington, D. C., Publication No. USBMRI
7588 (1972).
10. U. S. Dept. of Interior, U. S. Bureau of Mines, Washington, D. C.,
Publication No. USBMRI 7490 (1971).
54
-------
11. U. S. Dept. of Interior, U. S. Bureau of Mines, Washington, D. C.,
Publication No. USBMRI 7346 (1970).
12. U. S. Dept. of Interior, U. S. Bureau of Mines, Washington, D. C.,
Publication No. USBMRI 7219 (1969).
13. U. S. Dept. of Interior, U. S. Bureau of Mines, Washington, D. C.,
Publication No. USBMRI 6792 (1966).
14. North American Combustion Handbook, North America-Manufacturing
Company, Cleveland (1965), p. 31.
15. North American Combustion Handbook, North America Manufacturing
Company, Cleveland (1965), p. 35.
55
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A GUIDELINE FOR EVALUATING COMPLIANCE TEST RESULTS
(Isokinetic Sampling Rate Criterion)
R. T. Shigehara
Emission Measurement Branch, ESED, OAQPS, EPA
Introduction
The sampling rate used in extracting a particulate matter sample
is important because anisokinetic conditions can cause sample concentra-
tions to be positively or negatively biased due to the inertial effects
of the particulate matter. Hence, the calculation of percent isokinetic
(I) is a useful tool for validating particulate test results. Section 6.12
of the recently revised Method 5 states, "If 90 percent <_ I ^IIQ percent,
the results are acceptable. If the results are low in comparison to the
standard and I is beyond the acceptable range, or, if I is less than
90 percent, the Administrator may opt to accept the results."
This guideline provides a more detailed procedure on how to use
percent isokinetic to accept or reject test results when the sampling rate
is beyond the acceptable range. The basic approach of the procedure is to
account for the inertial effects of particulate matter and to make a
2
maximum adjustment on the measured particulate matter concentration. Then,
after comparison with the emission standard, the measured particulate matter
concentration is categorized (1) as clearly meeting or exceeding the
emission standard or (2) as being in a "gray area" zone. In the former
category, the test report is accepted; in the latter, a retest should
be done because of anisokinetic sampling conditions.
Procedure
1. Check or calculate the percent isokinetic (I) and the particulate
Published in Source Evaluation Society Newsletter 2(3), August 1977
56
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matter concentration (c ) according to the procedure outlined in Method 5.
Note that c must be calculated using the volume of effluent gas actually
sampled (in units of dry standard cubic feet, corrected for leakage).
Calculate the emission rate (E), i.e. convert c to the units of the
standard. For the purposes of this guideline, it is assumed that all
inputs for calculating E are correct and other specifications of Method 5
are met.
2. Compare E to the standard. Then accept or reject cg using the
criteria outlined below. (A summary is given in Table I):
a. Case 1 - I is between 90 and 110 percent. The concentration
c must be considered acceptable. A variation of ± 10 percent from 100
percent isokinetic is permitted by Method 5.
b. Case 2 - I is less than 90 percent.
(1) If E meets the standard, cg should be accepted, since
c can either be correct (if all particulate matter are less than about 5
micrometers in diameter) or it can be biased high (if larger than 5
micrometer particulate matter is present) relative to the true concentration;
one has the assurance that cg is yielding an E which is definitely below
the standard.
(2) If E is above the standard, multiply cg by the factor
(1/100) and recalculate E. If, on the one hand, this adjusted E is still
higher than the standard, the adjusted cg should be accepted; a maximum
adjustment which accounts for the inertial effects of particulate matter
has been made and E still exceeds the standard. On the other hand, if the
57
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adjusted E is lower than the standard, a retest should be done.
c. Case 3 - I is greater than 110 percent.
(1) If E exceeds the standard, cg should be accepted, since
c$ can either be equal to the true concentration or biased low relative
to it; one has the assurance that E is definintely over the standard.
(2) If E is below the standard, multiply c by the factor
(1/100) and recalculate E. If, on the one hand, this adjusted E is still
lower than the standard, the adjusted cg should be accepted; a maximum
adjustment which accounts for the inertial effects of particulate matter
has been made and E still meets the standard. On the other hand, if the
adjusted E exceeds the standard, a retest should be done.
Table I. Summary of Procedure
Case
90 - 110
Category
Decision
Accept
< 90
> 110
E < Em. Std.
Ead1 > Em. Std
Cgd/100)-*- Eadi <_ Em. Std.
E > Em. Std.
cs(I/100)-> Ead. < Em. Std,
Accept
Accept
Retest
-
Accept
Accept
58
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Summary
A procedure for accepting or rejecting particulate matter test
results based on percent isokinetic has been outlined. It provides a
mechanism for accepting all data except where anisokinetic sampling
might affect the validity of the test results. This procedure is one
of several useful tools for evaluating testing results.
References
1. Method 5 - Determination of Particulate Emissions from Stationary
Sources. Federal Register. 42_(160):41776-41782, August 18, 1977.
2. Smith, W. S., R. T. Shigehara, and W. F. Todd. A Method for
Interpreting Stack Sampling Data. Stack Sampling News. 1(2):8-17,
August 1973.
59
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TECHNICAI REPORT DATA
(Mi-asc read Instruction*
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