METHOD FORCALCULATING POWERPLANT 

### EMISSIONRATE

BY R. T. Shigehara, R. M. Neulicht: and W.S. Smith** Introduction In the final State Implementation Plans submitted byall 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 regulations 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/lo6 Btu)'. The Federal New 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. Toarrive at this expression, the Federal perfromance standard regulations call for the determination of the pollutant concentration (C), the effluent volumetric flow rate (Q,), and the heat input rate (QH). 

### In addition, the heat input rate must be confirmed by amaterial balance over the steam generator system. The purpose of this paper is to present an alternative method for arriving with improved accuracy at the expression of lb/lo6 Btu called for bythe State and Federal regulations without having to determine effluent gas volumetric flow rate, fuel rate, or fuel heat content.

Published in Stack Sampling News l(1): 5-9, 

### July 1973 * Emission Measurement Branch, ESED, OAQPS, EPA ** Entropy Environmentalists, 

### Inc. 1Derivation of the F-Factor Method Standard Method

In the standard method of calculating emission rates:



# cQs E = - QH (1)
where: E=pollutant emission, lb/lo6 Btu.

C=pollutant concentration, dry basis, lb/scfd. Q, =dry effl uent volumetric flow rate, scfdjhr. Q, =heat input rate, lo6 Btu/hr. F-Factor Method When the laws of conservation of mass and energy are applied, the following must hold true: (2)
where: V, =theoretical dry combustion products per pound of fuel burned,

scfd/lb. HHV=high heating value, lo6 Btu/lb.
20.9 - %O
_

2 - excess air correction factor. 20.9 Solving Equation 2for the ratio Q,/Q, and substituting into Equation 1 yields: V 20.9 E=' (i6V) (20.9 - "002~) (3)The amount of dry effluent gas (Vs) generated by combustion of afossil

fuel can easily becalculated from the ultimate analysis. The high heating value can beobtained from standard calorific determinations. The ratio, F, between Vsand HHVcan be calculated for various fossil fuels; Fis the effluent gas generated per lo4 Btu heat content:
vS F=‘TmqTmj- 

### (4) Values for Fcalculated from data obtained from the literature are summarized in Table I. Of course, this ratio can becalculated for each specific case, but the dry effluent per lo4 Btu varies nomore than about 53%. For this reason, these ratios will be considered as constants and will hereafter be called "F Factors." The use of these FFactors, aswill bediscussed later, eliminates the need for ultimate and calorific analyses. Alist of average FFactors derived from Table I is shown in Table 

### II.

3Table I FFactors for Fossil Fuels (Calculated from Data

Coal Anthracite 3

4 Total or avg. Bituminous 3

z 7 8 1: 4 Lignite 3

5 Total or avg. Oil Crude 11,124 Residuum 12 Distillate 12 Fuel 11 Total or avg. Gas Natural 4

13 Commercial 13 propane Commercial 13 butane Total or avg. in Literature)

3 101.0 2.4 1.2 1 102.8 - - 4 101.4 2.0 1.6 8 97.5 1.4 1.1 44 97.5 2.1 2.4 38 98.7 1.4 1.2 13 98.9 1.5 1.1 39 98.6 2.3 1.4 26 98.2 2.1 1.2 57 98.0 1.0 1.2 1 99.3 - - 1 97.5 - - 2 99.4 1.0 1.0 229 98.2 2.7 3.1
6 91.9 1.9 2.6 1 92.0 4 93.1 119 211 2 92.7 0.5 1.5 3 91.5 1.9 1.3 16 92.2 2.8 3.0
1 88.0 - - 4 86.7 0.3 0.5 2 86.8 0.1 0.1 2 89.0 0.3 0.3
9 87.4 2.2 1.2

_--_----- --____-.-. aStandard conditions are 7O"F, 29.92 in. Hg, and 0%excess air.

### Table II. Average FFactorsa Fuel -___. . _ -------__-- - ----- -.._ I -.__.__.-_ ..__ __ FFat ors scfd/lO Btub 4 .-- --.~.--.- ----- Coal-anthracite 101.4 Coal-bituminous, lignite 98.2 Oil-crude, residuum, distillate, fuel oil 1 92.2 Gas-natural, butane, propane 87.4 ------ -_- ------___ aDerived from Table I. b700F, 29.92 in. Hg., and 0%excess air. Useof FFactors Emission Rate Calculation When Q, and Q, are not measured or are unobtainable, FFactors can be

### used to calculate E. Substituting Equation 4 into Equation 3weobtain:
E=CF(20ag2090

- %02) where: F=FFactor from Table 

### II, in scfd/104 Btu. Equation 5shows that Ecan beobtained bysimply measuring the pollutant concentration and percentage oxygen and 

### byknowing the type of fuel being burned. Q, and Q, are no longer required. Material Balance Check If Q, and Q, are measured, FFactors can be used to check sampling data by comparing them with Fm.
where: QS Fm=QH



### 5Fuel AI'I~!ysis ChecL

If ultimate and proximate analyses are made, FFactors 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 lo4 Btu heat content. Discussion In the present method for calculating power plant emission rates, four separate quantities must bedetermined, 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 Quantity Measured 1. Pollutant concentration, C ; a. Pollutant mass i b. Dry gas volume j - . ----.-. - I 2. Effluent volumetric flow I / a. Velocity head rate, Qs b. Stack temperature :: Stack pressure Dry gas composition ! (Orsat) %CO %O %N e. Moisture conteit (dgier-' mined during measurement of 1 (b)) .l-l_l-- __._.- ----______- __.-_______ ----__I___ ._-..._.... -..--. 

### 3. Heat inptit rate, QH

.---_.__--..---. 4. Material !lalancc confir

mation 

### a. Coal input rate b. Calorific analysis of

coalFrom Table III, it is obvious that .the use of FFactors in calculating Erequires fewer measurements than are required by methodology in current use. Because there are fewer measurements, the inaccuracies attendant to measuring items 2through 4 (except for 2d) are not included in the final results. Granted that those measurements in 2must bemade for isokinetic sampling, but the errors made do not contribute directly to the emission standard calculation. Conclusion It has been shown that, for agiven type of fuel, arelationship exists between the fuel heat value and dry effluent that permits aconstant (F Factor) to becalculated 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 whi7e at most amaximum error of 3%may be propagated from the FFactor to the pollutant emission rate; and (3) if effluent volumetric flow rate (Q,) and heat input rate (Q,) are measured, an FmFactor can be calculated from those values and compared with the FFactor as amass balance check.
In short, use of the FFactor provides amethod less complex than the one nowemployed for calculating power plant emission rates and evaluating the sampling data.

71.



### 2. Federal Register, Standards of Performance for NewStationary 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.

8.

9.

10. References Duncan, L. J., Analysis of _Final State Imp!-enentatisn !.!_a~ - Rules and Regulations Environmental Protection Agency, Research .___ - -- Triangle Park, North Carolina 27711, Publication No. APTD-1334 (1972).

U.S. Dept. of interior, U.S. Bureau of Mines, Washington, D. C., Publication No. USBMRI 7490 (1971). U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D. C., Publication No. USMBRI No. 7346 (1970). U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, 0. C., Publication No. !JSMBRI 7219 (1969). U.S. Dept. of Interior, U.S. f'illreau of Mines, Washington, D. C., Publication No. USMBRI 6792 (1956). 

## 1.

8References {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).

.EMISSION C;lRRE",TION FACTORfor FQSSii FUEL-FIRED STEAM GENERATORS CO2CONCENTRATION APPRQACh Roy Neulicht* Introduction The Federal Standards of Performance for NewStationary 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/lo6 cal (lb/lo6 Btu). Toarrive at this emission rate, the existing method' 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 concentration (%02) has been proposed2 as the reference method to replace the existing method. The purpose of this paper is to present athird method, based on the F-Factor approach and employing adilution 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 aconstant. The method has two advantages: 1. Emission rates may bedetermined from wet basis concentration measurements without recalculation of the Fc-Factor. -_- * Emission Measurement Branch, ESED, OAQPS, EPA, RTP, NC Published in Stack Sampling News2(8): 6-11 I Febr!lary 19752. Use of CO2for correcting for dilution provides flexibility A by providing an additional method for determining emission rates; for example, in some cases measuring CO2may bemore convenient than measuring 02. Onedisadvantage of the CO2correction factor is that it cannot be used after control devices that alter the CO2concentration (e.g., wet scrubbers that remove CO2) or in situations where CO2is added. Derivation of Fc-Factor Method The method calculating emission rates as promulgated in the Federal Register' is: 

## Q

E=C>QH 

## (‘1 where: E=pollutant emission, g/lo6 cal (lb/106Btu)

C=pollutant concentration, dry basis, g/dscm, (lb/dscf) Q,= dry effl uent volumetric flow rate, dscm/hr (dscf/hr) Q,= heat input rate, lo6 cal/hr (lo6 Btu/hr) When the laws of conservation of mass and energy are applied, the following must hold true: (2)

where: Vt= total theoretical dry combustion products per unit

mass of fuel burned, dscm/g (dscf/lb) HHV=high heating value, lo6 Cal/g (lo6 Btu/lb)

11%co*m -- =dilution correction factor, ratio of measured car- %C02t bon dioxide and theoretical carbon dioxide produced

from combustion, dry basis Solving Equation 2for the ratio Q,/QH and substituting into Equation 1yields:

V Substituting $- (100) for %COzt yields:

t E=C 

## v’

i ) + (100) t (3)

(4)
where: Vc= theoretical volume of carbon dioxide-produced per unit

mass of fuel burned, scm/g (scf/lb) Elimination of Vt from Equation 4and rearrangement yields:

E=c

# c

1001 PC' %COzm/;HHV1
or 

### E=cj$C02mj c

"100 ' (F ) (5)

(6)
where: vC

Fc= HHV ~ ,the ratio of theoretical CO2generated by combustion to the high heating valve of the fuel combusted, scm/106 cal (scf/lO' Btu). The high heating value of the fuel combusted can beobtained from

12standard calorific determinations. The amount of theoretical carbon

dioxide generated by combustion can easily be calculated from the ult calculated for various fossil mate analysis. The ratio, Fc, has been
. ifuels from data obtained from the literature; these calculated ratios are summarized in Table I. For any fuel type, the ratio is found to beaconstant with amaximum deviation of It_5.9%. Average Fc- Factors for each fuel type are given in Table 

### II. Note that Equation 6for the determination of the pollutant emission rate (E) has been developed in terms of dry measurements. However, it is asimple matter to showthat wet basis measurements may be used. Given Equation 6and multiplying both the measured pollutant concentration (C) and the measured carbon dioxide concentration (%COpm) by the dry mole fraction (D) of the effluent gas yields;



## E=[(C)(WI (7)
or 03) where: Cw=pollutant concentration, wet basis, g/scm (lb/scf) %COzw=measured concentration of carbon dioxide, wet basis,

(expressed as percent). Equations 6and 8show that, using the average Fc- Factor approach, the pollutant emission rate (E) can beobtained bysimply knowing the type of fuel burned and measuring the pollutant and carbon dioxide concentrations

13on either awet or dry basis.

Determination of Fc- Factor - Rather than use an average Fc- Factor, the Fc - Factor can bedetermined on an individual case-by-case basis. Asalready stated, the high heating value of the fuel is determined from standard calorific determinations. The theoretical carbon dioxide generated bycombustion is easily calculated from the following equations based on stoichiometry3 and on information from an ultimate fuel analysis:

or vc= 0.200 x1

Vc= 0.321 %C

## o-4SC scm CO2 0 gfuel scf co2 lb fuel where: %C=percent carbon byweight determined from

ultimate analysis. Given the definition of the Fc - Factor,

Fc=4 and substituting Equations 9and 10yields:

F=0.200 x1o-4 %C C HHV for mekric units of scm/lO cal 

## (9 

## (10)

(11)

02) and F=0.321 %C

C HHV- for En8lish units of scf/lO Btu (13) Note: %Cand HHVmust beon aconsistent basis, e.g., if %Cis determined on an as-received basis, HHVmust also beon an as-received basis.

14Conclusion It has been shown that, for agiven fuel type, arelationship exists between the fuel calorific value and the theoretical effluent carbon dioxide, which permits an average Fc - Factor to be calculated within f 5.9% deviation. - This provides amethod 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 acalculation is given asfollows:
(14) where: E=pollutant emission, g/lo6 cal (lb/lo6 Btu)

C=pollutant concentration, g/scm (lb/scf) %C02=carbon dioxide content byvolume (expressed as

percent) Fc=afactor representing aratio of the volume of theoretical carbon dioxide generated to the calorific value of the fuel combusted. Note: Cand %C02may bemeasured either on awet or

dry basis provided that the same basis is used for each. Furthermore, average values of Fcare given for each fossil fuel type, and the necessary equations for determining the Fc- Factor on a case-by-case basis are presented.

15TABLE I. Fc- FACTOR FORFOSSIL FUELS Average
Fuel Type Literature Source scmaco2

Number of --__I Samples 106 cal Max. Dev.,% + - Coal Anthracite
Average Bituminous

Lignite Average OilCrude Residium Distillate Average Gas Natural Average Propane Average Butane Average 6 13 7 39 8 15 9 46 10 41 11 58 6 1 4 1

5 1 0.1585 12 6 0.1591 0.2202 0.2292 0.2218 0.2222 4.1 4.1 0.2029 0.2032 0.2065 0.2025 0.2022 0.2011 0.2105 0.2123 0.2027 5.9 5.2

655 610 613 5.1 2.2 160 4 3 0.1180 0.1168 3.9 2.0 13 2 0.1351 0.135? 1.0 1.0 13 2 0.1420 0.1420 I.o 1.o aStandard conditions are 70"F, 29.92 in. Hg, and 0%excess air. 16. TABLE II. AVERAGE Fc- FACTORS

Fuel Type suna CO2/106cal scfa C02/106 Btu Coal --Anthracite 0.222 1980 Bituminous and lignite 0.203 7810 Oil Gas 0.161 1430

Natural 0.117 1040 Propane 0.135 1200 Butane 0.142 1260

'Standard conditions are 7O"F, 29.92 in. Hg, and 0%excess air.

17REFERENCES

1. Federal Register, Standards of Performance for NewStationary Sources, 36:247, Part 

### II, December 23, 1971.

- 2. Federal Register, Proposed Emission Monitoring and Performance - Testing Requirements for NewStationary 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. fed.), Chemical Engineers' Handbook, 4th ed., McGraw Hill Book Company, N.Y., 1963, p.9-3. 5. North American Combustion Handbook, North America Manufacturing co., Cleveland, 1965, p.13. 6. Steam, The Babcox and Wilcox Co., NewYork, 1963, p.2-10. 7. 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. 8. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D.C. Publication No. USBMRI 7490, 1971. 

### 9. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D.C. Publication No. USBMRI 7346, 1970. 10. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington,D.C. Publication No. USBMRI 7219, 1969. 11. U.S. Dept. of Interior, U.S. Bureau of Mines, Washington, D.C. Publication No. USBMRI 6792, 1966.



### 18REFERENCES(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. "AMethod for Calculating Power Plant Emission Rates," Stack Sampling News, Volume 1, Number 1, July, 1973.

‘I9DERIVATION OFEQUATIONS FORCALCULATING POWERPLANT 

### EMISSIONRATES 02 Based Method -Wet and Dry Measurements R. T. Shigehara &R. M. Neulicht* 

### INTRODUCTION The Federal NewSource Performance Standards' 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. Shigehara et al.L developed ameans of determining 

### the emission rates in the desired terms using stoichiometric factors and oxygen (02) measurements. This procedure is expressed in equation form as follows: 

## E=CFCzo;“:gyo>

. "2 where: E=emission rate, lb/lo6 Btu

C=pollutant concentration, lb/scf F=fuel stoichiometric factor, scf/106 Btu %02=O2concentration, 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 %02on awet basis, questions have been asked about the derivation of Equation 1and howwet based measurements affect the equation. The derivation of the equations for wet and dry based measurements and alist of average F-factors are presented in this text. DERIVATION OFEQUATIONS The basic equation for calculating emission rate is given by: c

# Qs EC-..--QH (2) * Emission Measurement Branch, ESED, OAQPS, EPA, 

### July 1976 

## (1)

20. where: Qs=effluent volumetric flow rate, scf/hr Q, =heat input rate, lo6 Btu/hr. The product of Cand Q, is simply the mass rate; 

### thus, both Cand Q, must bedetermined on aconsistent basis, i.e. either wet or dry. To distinguish between wet and dry based measurements, the subscripts "w" and "d", respectively, will be used. Dry Basis 

### If Eis calculated from dry based measurements, Equation 2becomes: E= 'd Qsd QH (3) 

## Q sd can bewritten as: 

## Q sd =Sd +EAd (4) where: 'd =dry volumetric flow rate of effluent at stoichiometric conditions, dscf/hr EAd =dry volumetric flow rate of excess air in the effluent, dscf/hr. Anadjustment factor, Ad, which when multiplied by Q,d would adjust it to dry stoichiometric conditions, Sd$ can bederived as follows: 

## Q,,Ad=sd=Q,,-EAd (5)

EAd -- Ad=' Qs, (6) Since EAd =Q. /0.209, where Q,

2 2is the volumetric flow rate of O2 in the effluent and 0.209 is the fraction byvolume of O2 in dry air,

21Ad=1 

# Q”*

-Tj-.209 Q,, Noting that Q, /Q

2 sd is the proportion by volume of O2in the dry effluent mixture (Ozpd) and substituting into Equation 7, Adbecomes: 0 Ad=l-&&

. 20.9 - %OPd = 20.9 20.9 - %02d and sd =Q,, ( 20.9 1 Substituting Equation 9into Equation 2yields:
E 'd 20.9 ='d Q, 20.9 - %02d (8) 

## (9)
(10)

The ratio, S,/Q,, is simply the dry effluent gas at stoichiometric conditions generated per unit of heat input and can be calculated from ultimate and calorifit analyses of the fuel. These calculated ratios are defined as Fdand are surrunarized in Table I. Inserting Fd=S,/Q,, Equation 10 can be rewritten in its final form as: 20.9 E='d Fd20.9 - %Ozd 

## (11)

22Wet Basis If Eis calculated from wet based measurements, Equation 2becomes:
E

# cw Qsw

= 

## Q,
Asbefore, Qs, can bewritten as:

## Q SW=SW+EAw
If the combustion air is dry, then EA, = EAdand SWand Q,, will only include moisture derived from the fuel. It follows that: 

## Q,,A,=SW

=Q,,-EAd
EAd Aw=Lq SW

Q"* =l- 0.209 Q,,

=l- &
.

=20.9 - %02w 20.9

sw=

# Qsw

20.9 - %02w 20.9 (12)

(13)

(14) (15)
(16)
(17)
(18)
(19)

23sw 20.9 E=cw4, 20.9 - %o*w Defining SW/Q, as Fw' E=CwFw2. ;";gso

. a2w Toassume that combustion air is dry, however, is obviously not true. EA, must include moisture so that: EAd EAwa=1- B

wa (20)

(21)

(22)
where B,, is the moisture content in the ambient air; the subscript "a" is used to denote the inclusion of ambient moisture. Note also that Q,, and SW
nowinclude the moisture from the ambient air. Following steps that are similar to steps 14through 21: 

## Q swaAwa

## =Swa=

## Qswa

-EAwa
EAwa A =l-4 wa swa

EAd =‘-9 (1-B

swa wa)
QQ2 =l0.209 

## Qswa(1 -Bwa) (23) (24)
(25)

(26)

24=20.9 (1 - Bwa) -%02wa 20.9 (1 - Bwa)

s 20.9 (1 - Bwa) - %02wa wa=Qswa 20.9 (1 -Bwa)

S wa E - ='wa Q, 20.9 (1 - Bwa)

20.9 (1 - Bwa) - %02wa Defining Swa/Q, as Fwa:
E 20.9 (1 - B,,)
='wa Fwa20.9 (1 - Bwa) - %02wa (27)

(28)

(29)

(30)

(31)

The inclusion of ambient air in Fwa, however, is undesirable in that it becomes avariable. Written in terms of Fw, i.e. where ambient moisture is not included, Fwacan bewritten as: ThA (Bwa) S F =wa= sw+m wa QH QH (32)

25

-.-(33)

where ThA is the theoretical air required for complete combustion. Defining,
as before, SW/Q, as Fw, i.e. without ambient air moisture, and ThA/QH as FThA' i.e. theoretical air per unit of heat input, Equation 33can be rewritten as:
B F wa=Fw+FThA 1 

# 11 -waBwa (34)

(35) Substituting into Equation 31 and simplifying yields:

='wa Fw[1 - Bwa(1 -+$I]*O.9 (1 -':I, - %Ozwa (36)
Consider nowthe expression C1- Bwa(1 - FThA'Fw$ Average values of FThA/Fw are: coal =0.960; oil =0.948; gas =0.914. Anextreme case of ambient moisture content of 6.4% would occur at 100°F and 100% relative humidity. The expression cited above under these conditions would yield values of: coal =0.9975;oil =0.9967; and gas -;G-9945. Therefore, neglecting this cited expression

would introduce ii positive bias of nomore than 0.25 to 0.55%. Understanding this, Equation 36simplifies to its final form:*
20.9 --- E='wa Fw 20.9 (1 - Bwa) - %02wa (37)
Average values of Fware listed in Table II. From Tables Iand II it can beseen that Fd fdCtorS have amaximum arithmetic deviation Of f3.1 percent and Fwfactors, f3.8 percent.

REFERENCES 1. Standards of Performance for NewStationary Sources. Federal Register. (Washington) Part II. 363247, December 23, 1971. 2. Shigehara, R. T., R. M. Neulicht, and W. S. Smith. AMethod for Calculating Power Plant EmissiGn Rates, Stack Sampling News. I-:5-9, July 1973.

- * This equation was originally derived by G. F. McGowan, Vice President, Environmental Technology Division, Lear Siegler, Eng7ewood, Colorado.Table AVERAGE FdFACTORS FORFOSSIL FUELS Fuel type
CoalAnthracite Bituminous, lignite 

# I Oil Nat. gas, propane, butane 9 Samples, No.

4 229 16 -.~ 'd --. I--

dscf/106 Btua
10140 9820 9220 8740 Max. dev., %
+2.0 zk3.1 f3.0 +2.2
a Standard conditions are 70°F, 29.92 in. Hg, and 0%excess air.

Table II. AVERAGE FwFACTORS FORFOSSIL FUELS

Samples, No. Fuel type 

# Fw wscf/106 Btua
10580 10680 12000 10360 CoalAnthracite 7 Bituminous 129 Lignite 174 Oil 13 GasNatural Propane Butane Ia Standard conditions are 70°F, 29.92 in. Hg, and 0%excess air. 10650 10240 10430 Max. dev., %
+1.5 f2.7 k3.8 f3.5

a.8 20.4 f0.7

28SUMMARYOFFFACTOR METHODS FORDETERMINING EMISSIONS FROMCOMBUSTION SOURCES R. T. Shigehara, R. M. Neulicht, W.S. Smith,

and J. W. Peeler INTRODUCTION The Federal Standards of Performance for NewStationary 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 expressed in the same form. To arrive at this emission rate, the original method' required the determination of the pollutant concentration, effluent volumetric flow rate, and heat input rate. In the October 6, 1975, Federal Register,* an "F Factor" technique, which required only the determination of the fuel type, pollutant concentration, and the oxygen 

### (02) concentration, waspromulgated as aprocedure to replace the original method. At the same time, an FFactor approach, based on eith.er O2or carbon dioxide (CO*) measurements, waspromulgated for use in reducing the pollutant concentration data obtained under the continuous monitoring requirements to the desired units. Recently, wet FFactors,3 which allow the use of wet basis measurements of the same parameters, and FFactors for wood and refuse have been calculated. The purpose of this paper is to summarize the various methods and to present the calculated FFactor values for the different types of fuels. The various uses of FFactors and errors involved in certain applications and conditions are also discussed. SUMMARYOFMETHODS The first method, referred to simply asthe FFactor Method, is based on two principles: Published in Source Evaluation Society Newsletter l(4), November 1976 29
_-._.-.--1. The ratio of the quantity of dry effluent gas generated by combustion to the gross calorific value of the fuel is aconstant within any given fuel category. This ratio is normally called the dry FFactor; however, for purposes of this paper, it will be called the Fd Factor. 2. Anexcess 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 concentration (Cd) and percent oxygen ("02d). The emission rate (E) is calculated by the equation: E=Cd
If the moisture content of the derivative of Equation 1, which wou pollutant and oxygen concentrations flue gas (Bws) is determined, anatural Id allow direct wet basis measurements of

, i.e. Cwand %02w, respectively, is asfollows: Fd 20.9 20.9 - %02d> 

## (1)

E='w Fd 20.9

20.9 (1 -Bws) - %02w

# 1 (2)

This equation has been approved in principle bythe Environmental Protection Agency and may be used if it is demonstrated that Bwscan beaccurately determined and that any absolute error in Bwswill not cause an error of more than +1.5 - percent in the term 20.9 20.9 (1 - Bws) - %Opw * The second technique, called the FwFactor Method, is based onthe same two principles as the Fd Factor Method, except that the two quantities, the effluent gas and the oxygen concentration, are determined on awet 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 FFactor or the FwFactor. The use of this technique, however, requires in addition to the wet pollutant concentration (Cw) and oxygen (%02w) the determination of the fractional moisture content of the air (Bwa) supplied for combustion. (Guidelines for this determination will be discussed later.) The equation for calculating the emission rate is:

This equation is asimplification of the theoretically derived equation.3 Under typical conditions, apositive bias of nomore than 0.25 percent is introduced. The third procedure, the FcFactor Method, is based on principles related to but slightly different than those for the FdFactor and F, Factor Methods: 1. For any given fuel category, aconstant ratio exists between the volume of carbon dioxide produced by combustion and the heat content of the fuel. This ratio is called the FcFactor. 2. The ratio of the theoretical carbon dioxide produced during combustion and the measured carbon dioxide provides anexact basis for dilution correction. This method requires measurement of the pollutant concentration and percent carbon dioxide (%C02) in the effluent stream. Measurements may bemade on awet or dry basis. Using the subscripts, "d" and "w", to denote dry and wet basis measurements, respectively, the equations for calculating Eare: (4)

37DETERMINATION OFFFACTORS

Values of Fdin dscf/106 Btu, Fwin wscf/106 Btu, and Fc in scf/106 Btu, may bedetermined on an individual case-by-case basis using the ultimate analysis and gross calorific value of the fuel. The equations are:
Fd=lo6 (3.64 %H+1.53 %C+0.57 %S+0.14 %N-0.46 %0) GCV 

## (5)

Fw=lo6 (5.57 %H+1.53 %C+0.57 %S+0.14 %N-0.46 %0+0.21 %H20*) GCVw

Fc=lo' (0.321 %C)

GCV where: H, C, S, N, 0, and H20 are the concentrations byweight (expressed in percent) of hydrogen, carbon, sulfur, nitrogen, oxygen, and water from the ultimate analysis. (* Note: The %H20term may beomitted if %Hand %0include the unavailable hydrogen and oxygen in the form of H20.) GCVis the gross calorific value in Btu/lb of the fuel and must always bethe value consistent with or corresponding to the ultimate analysis. For determining Fw, the ultimate analysis and GCV, must beon 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 aparticular fuel are not known. For most commonly used fuels, tabulated average FFactors may be used instead of the individually determined values. These average values of Fd, Fw, and
FC’ calculated from data obtained from the literature, 2-14 are given in Table I. FFactors for wood and bark are also listed in Table I, and factors for various types of refuse are listed in Table II

32. maximum CO2concentration that the

this number into 20.9, aratio cal culated from the ultimate analyses II. The ratio of Fcto Fdtimes 100 yields the ultimate percent CO2or the dry flue gas is able to attain. Bydividing led the F. Factor is obta ined. F. values calof the various fuels are given in Tables I and
F. values can also becalculated from CO2and O2data obtained in the field by using the following equation.
F, =20.9 - %O*d %co&, (8)
These calculated F. values can be used to check Orsat data or other analyses of CO2and O2that have been adjusted to adry basis. The process simply involves comparing F. values calculated from Equation 8with the values listed in Table I or II. Further details of this validation procedure are outlined in Reference 15. ERRORS ANDAPPLICATION ULTIMATE CARBON DIOXIDE

The derivations of Equations 1through 4are discussed in References 3, 4, and 5. The following discussion gives further explanation of the FFactors and describes some of the problems and errors that arise in applying the FFactor Methods. Several uses for FFactors in addition to calculating emission rates are outlined. Deviation in FFactors The FFactors were calculated from data obtained from the literature. In the October 6, 1975, Federal Register,' the values of Fdand Fcwere calculated bysumming all data points and deviat ions from the extreme va dividing bythe total number of samples. Then the ues (highest and lowest) were determined. The
33higher of the two values, termed "maximum percent deviation from the average

FFactors," are listed in parenthesis in Table I. These deviations are probably due to differences in the composition of the fuel, and may also include variations due to the analytical methods and analysts (laboratories). The standard 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 Fdand FcFactors, it wasdetermined that the midpoint value would beabetter value than the average for small samples and for data taken from the literature. Therefore, the FwFactors and the values for wood and refuse are midpoint values rather than arithmetic averages. The associated deviations are termed, "maximum percent deviation from the midpoint FFactor." FwFactors for refuse, wood, and wood bark were not calculated because of the high variability of free moisture contents. For example, the moisture in bark may vary from 20 percent (air dried) to 75 percent (hydraulic debarking).6 Free moisture content variations of +15 percent introduce about 5percent variation
. - However, for lignite, the moisture contents vary only from about 33to 45 percent. This range causes adeviation of 3.8 percent from the midpoint FwFactor, which enabled an FwFactor to be established. Incomplete Combustion The assumption of complete combustion is made in the derivation of all FFactor 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 FFactors. However, adjustments to the measured CO2or O2concentration can be made, which would minimize the magnitude of the error when applying Equations l-5.

34These adjustments are given by the following equations:

.

. ("Co~)adj = %C02 + %CO (%O*)adj =%O*-0.5 %CO 

## (10) Bymaking these adjustments, the error amounts to minus one-half the concentration of COpresent. Thus, if 1percent CO(an extreme case) is present, an error of minus 0.5 percent is introduced. Without adjusting the CO2or O2concentration, acombustion source having 11 percent CO*, 1percent CO, and 6percent O2will result in about plus 9percent error for the FcFactor Method and about plus 3percent for the FdFactor and FwFactor 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 FFactor 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 matter, the FFactor Methods are only slightly affected. In other words, if any portion of the fuel goes through the combustion process unburned, the FFactor Methods will not include as heat input the calorific value associated with the uncombusted matter, and aslight 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 alower FFactor than the calculated values. Since ahigher proportion of fixed carbon than volatile matter generally remains in the ash, the FcFactor Method is affected more than the FdFactor andFwFactor Methods. For example, assume that 100 lb of acoal, which has

558%C, 5.7% H, 1.1% N, 3.2% S, 21.5% 0, and 12.6% ash (percent byweight, as received basis), is burned and 5lb fixed carbon remains in the ash. About plus 2.3 percent error is incurred with the FcFactor and less than 1percent with the FdFactor and FwFactor Methods. Effect of Wet Scrubbers Whenwet scrubbers are used, aportion of the carbon dioxide may be absorbed bythe scrubbing solution. Therefore, the FcFactor Method will yield an emission rate higher than the actual rate. If agas stream having 14%CO2before the scrubber loses 10 percent of the C02, or 1.4% C02, the error is about plus 13 percent. The FdFactor Method is also affected by the loss of CO2in the scrubber, but to alesser degree than the FcFactor Method. If the gas stream has 6%02 and 1.4% CO2is lost in the scrubber,,the error will beabout plus 2percent. The F, 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 O2concentration will be lower than actual, which would tend to yield lower than true numbers. When the scrubbing solution is lime or limestone, the FcFactor Method may be used after wet scrubbers. It is generally assumed that due to the optimum operating conditions, the amount of CO2absorption is minimized and, therefore, the application of the FcFactor Method will not yield appreciable errors. However, with limestone scrubbers, there is apossibility of CO2being added to the gas stream due to the reaction of SO2with the limestone. Therefore, the FcFactors must be increased by 1percent.
36Determination of Ambient Air Moisture Guidelines have been developed for the determination of Bwa, 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 Bwabyon-site instrumental measurement provided that the absolute accuracy of the measurement technique can be demonstrated ,to bewithin +0.7 percent water vapor. In lieu of actual measurement, Bwamay be estimated as follows: (Note that the following estimating factors are selected to assure that any negative error introduced in the emissions bythe estimating term percent. However, posi as5percent may be int 20.9 20.9 (1 - Bwa) - %Ozws will not be larger than -1.5 tive errors, or over-estimation of emissions, of asmuch reduced depending upon the geographic location of the facility and the associated range of ambient moisture.) " Bwa=0.027. This factor may be used as aconstant value at any location. 2* Bwa=highest monthly average of Bwathat occurred within acalendar year at the nearest Weather Service Station, calculated using data for the past 3years. This factor may be used on an annual basis at any facility. 3a Bwa=highest daily average of Bwathat occurred within acalendar month

Sampling Ambat the nearest Weather Service Station, calculated for each month for the past 3years used as an estimating factor for the respective ca7endar month. Location and Sampling Points ent air leakage into an exhaust system may cause variations across the duct or stack in the relative concentrations of CO2and 02. For this reason, the Federal regulations2 specify that CO2or O2bemeasured simultaneously and approximately at the same point as the gaseous pollutants measurements.For particulate emission performance tests, which require traversing, it

is specified that the O2samples beobtained simultaneously bytraversing the duct at the same sampling location used for each run of the Method 5. This requirement may besatisfied byattaching astainless steel tube to the particulate sampling probe and, using asmall diaphragm pump, obtaining an integrated gas sample over the duration of the run (of Reference 1). The sample should beanalyzed using an Orsat apparatus. Asan alternative to traversing the same sampling points of Method 5, aminimumof 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, FFactors have several other uses. If=Q,,, the dry effluent volumetric flow rate, or Q,,, the wet effluent volumetric flow rate, and Q,, the heat input rate, are measured, avalue of Fd, Fw,or Fc may be calculated. These equations are given below: 

## Q sd Fd(calc) =$- 20.9 - %02 20.9 (11) 

## Q sw Fw(calc) =Q, 20.9 (1 -Bwa) - %02w 20.9

Fc(calc) -- (12)
(13)
The calculated values may then becompared to tabulated values of the FFactors to facilitate amaterial balance check.
38. If desired, Q, can be calculated by using the Equations 11 through 13.

In the past, it has been observed that the measurement of Q, has been significantly greater than the stoichiometric calculations rates. The discrepancy is usually due to errors in determining Q,. Dueto aerodynamic interferences and improper alignment of the pitot tubes, higher than real readings have been obtained. Therefore, errors in measuring Q, are positive, which.leads to higher than true firing rates. If an ultimate analysis and calorific determination of aparticular fuel are made and the FFactor value is calculated, the accuracy of the results may be checked by comparison with the tabulated FFactors. SUMMARY The various FFactor Methods have been summarized and calculated FFactors 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 FFactor Method for calculating power plant emission rates were discussed and other uses of the FFactors were outlined.

39TABLE I. FFACTORS FORVARIOUS FUELSP-14'aybyc

Fuel Type CoalAnthracite Bituminous Lignite Oil GasNatural Propane Butane Wood Wood Bark Fd dscf/106 Btu
10140 (2.0) 9820 (3.1) 9900 (2.2) 9220 (3.0)

8740 (2.2) 8740 (2.2) 8740 (2.2) 9280 (1.9)* 9640 (4.1) 

# Fw wscf/106 Btu
10580 (1.5)* 10680 (2.7) 12000 (3.8) 10360 (3.5)

10650 (0.8) 10240 (0.4) 10430 (0.7)

-----------

----------- 

# Fc scf/106 Btu
1980 (4.1) 1.070 (2.9) 1810 (5.9) 1.140 (4.5) 1920 (4.6) 1.076 (2.8) 1430 (5.1) 1.346 (4.1)

1040 (3.9) 1.749 (2.9) 1200 (l.o)* 1.510 (1.2)* 1260 (1.0) 1.479 (0.9) 1840 (5.0) 1860 (3.6) FO -

1.050 (3.4) 1.056 (3.9)

a Numbers in parenthesis are maximum deviations (%) from either the midpoint or average FFactors. b To convert to metric system, multiply the above values by 1.123 x10e4 to obtain scm/106 cal. ' All numbers below the asterisk (*) in each column are midpoint values. All others are averages.TABLE II. MIDPOINT FFACTORS FORREFUSE2-14Yayb

Paper and WoodWastesC Lawnand Garden Wastesd Plastics Polyethylene Polystyrene Polyurethane Polyvinyl chloride Garbagee Miscellaneous Citrus rinds and seeds Meat scraps, cooked Fried fats Leather shoe Heel and sole composition Vacuum cleaner catch Textiles Waxed milk cartons Fd dscf/lO'Btu 9260 (3.6) 9590 (5.0)
9173 1380 1.394 9860 1700 1.213 10010 1810 1.157 9120 1480 1.286 9640 (4.0) 1790 (7.9) 1.110 (5.6)
9370 9210 8939 9530 9480 9490 9354 9413 FC wscf/106Btu 1870 (3.3) 1840 (3.0)

1920 1540 1430 1720 550 700 840 620 FO 1.046(4.6) 1.088 (2.4)

1.020 1.252 1.310 1.156 1.279 1.170 1.060 1.040

a Numbers in parentheses are maximum deviations (%) from the midpoint FFactors. b To conltert to metric system, multiply the above values by 1.123 x10B4 to obtain ‘ scm/lO cal.

l ' Includes newspapers,

green logs, brown paper, corrugated boxes, magazines, junk mail, wood,

rotten timber. d Includes evergreen shrub cuttings, flowing garden plants, leaves, grass.
e Includes vegetable food wastes, garbage (not described). 41REFERENCES

1. Standards of Performance for NewStationary 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, O2Based Method -Wet and Dry Measurements. Emission 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. AMethod for Calculating Power Plant Emissions. Stack Sampling News. 1 (1):5-g. 

### July 1973. 5. Neulicht, R. M. Emission Correction Factor for Fossil Fuel-Fired Steam Generators: CO2 Concentration Approach. Stack Sampling News. 2 (8);6-11. 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.

4210. 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. NewYork, McGraw-Hill Book Company, 1967. Chapter 7, p.19. 12. MacKnight, R. J. and J. E. Williamson. Incineration: General Refuse Incinerators. 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. NewYork, 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.

43VALIDATING ORSATANALYSIS DATAFROMFOSSIL-FUEL-FIRED UNITS R. T. Shigehara, R. M. Neulicht, and W.S. Smith INTRODUCTION In the September 11, 1974 Federal Register,' anewreference method for calculating the pollutant emissions from fossil fuel-fired steam - generating units of more than 250 million Btu/hr heat input wasproposed. 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. 2 Recently, another method has been published3 that uses the same principle, except that carbon dioxide (C02) concentration is used to adjust for excess or dilution air. The validity of both methods relies heavily onthe accuracy of either the O2or CO2measurement. 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 O2and CO2measurements are obtained from Orsat analyses, guidelines are given for validating the data from these analyses. C02-O2 RELATIONSHIP Since air is used for the combustion process, the law of conservation of mass demands that: %02+F. %C02=20.9 (1) where: %02=O2content byvolume (expressed as percent), dry basis

%C02=CO2content byvolume (expressed as percent), dry basis F. =fuel factor; depends on the type of fuel burned 20.9 =O2content in air by volume (expressed as percent), dry basis.
Publirilcd in 5tacb .'arwlinc '1~5 /1(Z): ?1-?f- , "un115t "'76
. 44Solving for Fo, weobtain: 20.9 F. = - %02

%CO* 

## (2)
The factor F. is mainly afunction of the hydrogen (H) to carbon (C) ratio in the fuel.4 At zero percent excess air (i.e., when fuel is burned completely with stoichiometric amount of air), Equation 2simplifies to: 

# F.=* (3) where (%C02)ult is the ultimate CO2or the maximum CO2concentration 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:5 

## wo2)ult= 0.321 %C(100)

1.53 %C+3.64 XH+0.57 %S+0.14 %N- 0.46 %0 (4) where %C, %H, %S, %N, and %0are the percent byweight of carbon, hydrogen, sulfur, nitrogen, and oxygen, respectively, obtained from the ultimate analysis. Equations 1through 4can be used to check Orsat data or other analyses of CO2and O2that have been adjusted to adry basis. The process simply involves comparing F. values calculated from Orsat analyses (Equation 2) with F. values calculated from the ultimate analyses of the fuels being burned (Equations 3and 4). Alternatively, agraphical approach may be used. With CO2asthe abscissa and O2as the ordinate on arithmetic paper (see Figure 1), astraight line drawn between 20.9% O2and the ultimate CO2calculated from the ultimate analysis (Equation 4) represents Equation 1. The Orsat analysis

4.516-
14-

B6-

CO2(DRY),percent

Figure 1. Graph construction for checking Orsat data. 46is checked by plotting the data points on this graph. Equation 1or 2assumes complete combustion of the fuel. If carbon monoxide (CO) is present in measurable quantities, the O2and CO2must be adjusted when using the equations as follows:

(%"2)adj = %C02 + %CO (%02)adj =%02-0.5 %CO (6) (5)

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 beapplicable to sources that (1) remove CO2(e.g., sources that use wet scrubbers) or 02, or (2) add O2and N2in aproportion different from that of air or (3) add CO2 (e.g., cement kilns). SUMMARYOFAVERAGE F. FACTORS ANDULTIMATE 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. 6-15 Some of the average F, factors and (%COp)ult were calculated by use of asmall 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 explained later. F, and ULTIMATE CO2TOLERANCES Asmentioned earlier, the purpose for the O2or CO2measurements is primarily to adjust the pollutant concentrations for dilution air. In
47Table I Fo Factors for Fossil Fuelsa Literature Number of Average Maximum Deviation, % Fuel type source samples FO (%co*)u,t + 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 3

7 1 8 3
8 13 9 38 10 13 11 39 12 26
8 1 6 1 16 198

7 1 14 6 14 4 14 2

15 6
15
15 1.0786 19.38 1.0525 19.86 1.0671 19.59 1.0699 19.53 1.1202 18.66 1.1407 18.32 1.1336 18.44 1.1450 18.25 1.1435 18.28 1.1398 18.34 1.0779 19.39 1.0791 19.37 1.0761 19.42 1.0761 19.42
1.3628 15.34 1.3561 15.41 1.3280 15.74 1.3464 15.52 1.3465 15.52
1.7594 1.7349 1.7489 1.5095 1.5095 1.4791 1.4791 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

1.8
1.2
0.9 4.1

2.9
1.2
0.9
a Standard conditions are 7O"F, 29.92 in. Hg, and 0%excess air. 48evaluating the effect of the inaccuracy of the measurement on the final

result, it is important to consider not only the 02 and CO2relationship, but also the level of their concentrations. Anexplanation follows. The adjustment factors for dilution air are:

Fdo =20.9 - K. 20.9 - %02
KC Fdc =- %C02 (7)
(8) where: Fdo and Fdc =adjustment factors for dilution air based on O2and C02, respectively K. and Kc=reference O2and CO2concentrations, respectively %02and %C02=percent byvolume of O2and CO2, respectively, dry basis

20.9 =percent by volume of O2in air, dry basis. The relative errors introduced in the adjustment factors by inaccuracies of the O2and CO2measurement can beapproximated bythe following equations (also shown graphically in Figure 2):

Edo= d(%02) 20.9 - %O* x100 

## (9) d(%C02) Edc= %CO2 x100 (10)
where: Edo and Edc=relative errors introduced in the adjustment factors based on 02 and C02, respectively, percent

49

# I I

2.4- 1 I I I

-,1.6+- 170* 0‘

g 0.8 a ta Ly I

0.6i--- / /



## I 0 2 4 6 8 10 12 14 16 18 LEVEL OFCO2OR02,percent Figure 2. Relative errors resulting from inaccurate CO2 or02 measurements.
50. d(%02) and d(%C02) =deviation from the true value of O2and COz, respectively, percent byvolume. If d(%02)'s and d(%C02)'s can be determined or estimated, Figure 2 can bevaluable in making decisions or evaluations. For example, if the CO2level is about 12 to 14%, Fyrites * that are capable of measuring CO2to within 0.5% would be adequate for making Fdc calculations. If the CO2concentration is down at the 2%level, however, it can beseen that to achieve, for example, a5%accuracy, ameasurement to within 0.1% CO2is required. Thus, Orsats tiith burettes capable of measuring to within 0.1% C02, not Fyrites, should be used. Toestimate the tolerances of F. and the ultimate CO2for adesired accuracy of Ed0or Edc, the following relationship is helpful:

dFO -= d(%C02)ul t
_ i d(%O& FO (%co2)u, t - - 20.9 - %O* - Equation 11shows that the tolerance of F. or (%C02)ult is the sumof Edoand Edc. With the understanding that Ed0and Edc can bearange of plus or minus values, however, the tolerance of F. or (%C02)u,t must be-limited to the same magnitude of Ed0 or Edc to ensure that Ed0or Edcwill be less than that magnitude. For example, to limit Ed0or Edc to +5%, F. or (%C02)ult - must also be limited to +5%. PROCEDURE

. Based on the previous discussion, the following procedure can be

established for validating Orsat analysis data: rTrade name; not to be considered an endorsement.1. Decide tolerances for Ed0or Edc.

2. If ultimate analysis of fuel being burned is available, calculate F. using Equations 3and 4or (%C02)ult using Equation 4. Otherwise, use average values from Table I. Then calculate the limits of tolerance for F. or (%C02)ult. For example, if a55%tolerance is desired, the tolerance limits would be 0.95 and 1.05 times the calculated F, or (%C02) ult. Construct graphs as in Figure 1, using these tolerance limits. 3. Tocompare field Orsat data, calculate Fo, using Equation 2, or plot the data points onthe 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 adouble-check of the Orsat apparatus and analyses run byanother person, consistently yield values that are rejected, the average values should be considered suspect and the Orsat analyses accepted. Agraphical nomograph technique using a55%tolerance level and average values from Table I is shown in Figure 3. SUMMARY For any given fuel burned with air, arelationship between O2and CO2 must exist. This relationship can be used to advantage to validate Orsat analysis data. Onthe basis of ultimate analysis or average values of F. or myu,t ca?culated from data in the literature, aprocedure has been presented for validating Orsat analysis data.

52ANTHRACITE, LIGNITE

NATURAL GAS

Figure 3. Nomograph for checking Orsat data t 5%inEd0 orEdc.

53REFERENCES 1. Federal Register, Proposed Emission Monitoring and Performance Testing Requirements for NewStationary Sources, 39:177, Part 11 (September 11, 1974). 2. Shigehara, R. T., Neulicht, R. M., and Smith, W. S., "AMethod 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 FuelFired Steam Generators: CO2Concentration 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 Wilcox Company, NewYork (1963), p. Z-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).

5411. 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. USBMRT 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 Anerica,Manufacturing Company, Cleveland (1965), p. 31. 15. North American Combustion Handbook, North America Manufacturing Company, Cleveland (1965), p. 35.

55AGUIDELINE FOREVALUATING COMPLIANCE TEST RESULTS (Isokinetic Sampling Rate Criterion)

R. T. Shigehara Emission Measurement Branch, ESED, OAQPS, EPA Introduction The sampling rate used in extracting aparticulate matter sample is important because anisokinetic conditions can cause sample concentrations to be positively or negatively biased due to the inertial effects of the particulate matter. Hence, the calculation of percent isokinetic (I) is auseful tool for validating particulate test results. Section 6.12 of the recently revised Method 5' states, “If 90 percent 5 I2 110 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 amore detailed procedure on howto 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
n maximum adjustment on the measured particulate matter concentration.L 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, aretest should bedone because of anisokinetic sampling conditions. Procedure 1. Check or calculate the percent isokinetic (I) and the particulate Published in Source Evaluation Society Newsletter Z(3), August 1977 56matter concentration (cs) according to the procedure outlined in Method 5.

Note that cs 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 cs to the units of the standard. For the purposes of this guideline, it is assumed that all inputs for calculating Eare correct and other specifications of Method 5 are met. 2. Compare Eto the standard. Then accept or reject cs using the criteria outlined below. (Asummary is given in Table I):

a. Case 1- I is between 90and 110 percent. The concentration cs must be considered acceptable. Avariation of + 10 percent from 100 percent isokinetic is permitted by Method 5.

b. Case 2- I is less than 90 percent. (1) If Emeets the standard, cs should beaccepted, since cs 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 cs is yielding an Ewhich is definitely below the standard. (2) If Eis above the standard, multiply cs bythe factor (I/100) and recalculate E. If, onthe one hand, this adjusted Eis still higher than the standard, the adjusted csshould beaccepted; amaximum adjustment which accounts for the inertial effects of particulate matter has been made and Estill exceeds the standard. Onthe other hand, if the

57adjusted Eis lower than the standard, aretest should bedone. C. Case 3- 

### I is greater than 110 percent. (1) 

### If Eexceeds the standard, cs should beaccepted, since cs can either be equal to the true concentration or biased low relative to it; one has the assurance that Eis definintely over the standard.

(2) 

### If Eis below the standard, multiply cs by the factor (I/100) and recalculate E. If, on the one hand, this adjusted Eis still lower than the standard, the adjusted cs should be accepted; amaximum adjustment which accounts for the inertial effects of particulate matter has been made and Estill meets the standard. Onthe other hand, if the adjusted Eexceeds.the standard, aretest should bedone.
Table 

### I. Summary of Procedure

E>Em. Std.

58Summary

. Aprocedure for accepting or rejecting particulate matter test

results based on pcvzent isokinetic has been outlined. It provides a mechanism for accepti:lg 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. AMethod for Interpreting Stack Sampling Data. Stack Sampling News. 'l-(2):8-17, August 1973.Koger T. Shigehara (Editor) _-__--- ----- ~---~- ..-_ ~~ ~---.- ~%RFORMING ORGANIZATION NAME AND ADDRESS ~_~.--- -- ~~p-~-~~~~MLLEM~~~‘N~~.-. ~-___~ - U.S. Environmental Protection Agency Emission Standards and Engineering Division (._----F_-.----~ ,ll. CONTRACT/GRANT NO Emission Measurement Branch Research Triangle Park, NC27711 -__-_.~---- ____ - 2.SPONSORING AGENCY NAME AND ADDRESS --__--- - ----..__ ._ ___. t13. TYPE OF REPORT AND PERIOD COVEREO Same as above.

5.SUPPLEMENTARY NOTES

-I 6.ABSTRACT "Stack Sampling Technical Information" is afour-volume collection of monographs and papers which have been compiled by the Emission Measurement Branch, ESED, OAQPS. The information specifically relate to current EPAtest methods and compliance test procedures. The data presented in some of these documents have served as the basis for anumber of revisions made in the EPAReference Methods 1through 8. Several of the documents are also useful in determining acceptable alternative procedures.

_Gas Sampling Filtered Part i GasAnalysis KEY WORDS AND DOCUMENT ANALYSIS

__ .._~~ ~-~~. --~~----~--- - DESCRIPTORS b.iUENTIFlERSi’OPEN ENDED TERMS

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