Table 4-2

F3SCR Technology Impact Factors for SCR

Coal Type F3SCR 

PRB 0.17

Other Coals 1 (no data available) 
Table 4-3

Summary of F2 Factors for Air Heater Removal of Sulfuric Acid

Boiler Type Fuel F2 Comment 

All Boilers Low S Eastern Bit 0.5 Average of measurements at 7 units. 

All Boilers Med-High S Eastern Bit (S >2.5%) 0.85 Two data points only. 

All Boilers PRB 0.36 Based on one data point. 

Table 4-4

Summary of F2 Factors for Particulate Control Devices (ESP, Baghouse)

Equipment Type Coal Type F2 Factor Comment or Observation 

Cold-side ESP Low S Eastern Bit 0.63 Average of measurements at 4 units. 

Cold-side ESP High S Eastern Bit (>2.5%) 0.77 Average of measurements at 3 units. 

Cold-side ESP Subbituminous (PRB) 0.72 Based on one measurement at one unit. 

Hot-side ESP All 0.63 Based on one measurement at one unit. 

Baghouse Subbituminous coal 0.1 Two data points. 

Table 4-5

Summary of F2 Factors for Wet, Dry FGD Equipment and Additives

FGD Type Coal Type F2 Factor Comment or Observation 

Wet: Spray Tower E. Bituminous 0.47 Seven data points. 

Wet: Spray Tower PRB or Lignite 0.4 Two data points. 

Wet: Venturi Tower All coals 0.65 Based on bituminous coal only; limited data merit assigning same factor for other coals. 

Dry FGD and baghouse All coals 0.01 Two data points. 

Mg-Ox mixed w/fuel oil All fuel 0.5 One data point. 

Mg-Ox into furnace All fuel 0.5 One data point. 
Table 4-1

Summary of Fuel Impact Factors (F1) for Steam Generating Units

Fuel Equipment F1 Comment 

Med-High S 

Eastern Bituminous 

(>2.5%) Dry Bottom Boiler 0.011 Seven data points. 

Med-High S 

Eastern Bituminous 

(>2.5%) Cyclone 0.016 One data point. 

Low S Eastern Bit. Dry Bottom Boiler 0.0082

Average of measurements at 16 units; slight increase 

in penetration compared to Harrison (2005). 

W. Bituminous Dry Bottom Boiler 0.00111 One data point. 

W. Bituminous Cyclone 0.0022 One data point. 

Subbituminous/PRB All Boilers 0.0019

Average of 7 units; an increase in penetration 

compared to Harrison (2005). 

Lignite Dry Bottom Boiler 0.0044 One data point. 

Lignite Cyclone 0.00112 One data point. 

Petroleum coke Boiler 0.04 One data point. 

Natural gas Boiler 0.01

#2 Fuel oil Boiler 0.01

#6 Fuel oil Boiler 0.025

Used oil Boiler 0.0175

Natural gas CT 

See Table 6-

1 

#2 Fuel oil CT 

See Table 6-

1 

Natural gas CC 0.0555

#2 Fuel oil CC 0.0555 New category in 2007. 

Other Alternative 

Fuels Any 0.04

Other Alternative 

Fuels, co-fired 

w/coal, >75% heat 

throughput NA Use Coal F1, in absence of any applicable data. 
EMComb = K • F1 • E2

K = 3063 lb H2SO4/ton SO2

F1 = 0.0019 Fuel Impact Factor from F1 table

Equation 4-2b E2 = K1 • K2 • C1 • S1

C1 = 500 Coal burn, tons/hr

S1 = 0.27 Coal sulfur weighted average, %

K1 = 0.02 ton SO2/%S

K2 = 0.875 0.95 for bituminous coals

0.875 for subbituminous coals

= 0.55 to 0.85 for lignite, based on the Na content

1.0 for oil

E2 = K1 • K2 • C1 • S1

E2 = 0.02 * 0.875 * 500 * 0.27

E2 = 2 SO2 mass rate, tons/hr

EMComb = K * F1 * E2

EMComb = 3063 * 0.0019 * 2

EMComb = 13.75 total H2SO4 manufactured from combustion, lbs/hr

Sulfuric Acid Released from Combustion (ERComb)

Equation 4-3 ERComb = EMComb • F2 (all that apply)

ERComb = EMComb • F2 (AH) • F2 (PM) • F2 (FGD)

ERComb = 14 * 0.36 * 0.72 * 1

ERComb = 3.56 total H2SO4 released from combustion, lbs/hr

Sulfuric Acid Manufacture by SCR (EMSCR)

EMSCR = K • S2 • fsops • E2• F3SCR = Total H2SO4 manufactured from SCR, lbs per hour

K = 3063 lb H2SO4/ton SO2

S2 = 0.005 SCR catalyst SO2 oxidation rate (specified as a decimal, typically from 0.001- 0.03)

fsops = 1 for continuous operation

E2 = 2 SO2 produced, tons per hour

F3SCR = 1 Technology Impact Factor, for SCR Table 4-2

EMSCR = K • S2 • fsops • E2 • F3SCR

EMSCR = 3063 * 0.005 * 1 * 2 * 1

EMSCR = 36.18 = Total H2SO4 manufactured from SCR, lbs per hour
Equation 4-11a: Manufacture

TSAM = EMComb + EMSCR/SNCR + 

TSAM = EMComb + EMSCR/SNCR + EMFGC

TSAM = 14 + 36

TSAM = 49.93 = Total H2SO4 manufactured, lbs per hour

Sulfuric Acid Released from SCR and SNCR

Equation 4-5 ERSCR = [EMSCR – (Ks • B • fsreagent • SNH3)] • F2x

ERSCR = Total H2SO4 released from SCR, lbs per hour

EMSCR = Total H2SO4 manufactured from SCR, lbs per hour

Ks = 3799 Conversion factor

HV = 8,950 Btu/lb

B = 8.95E-03 Coal burn in TBtu/hr

fsreagent = 1 fraction of SCR operation with reagent injection

SNH3 = 2 NH3 slip from SCR/SNCR, ppmv at 6% O2, wet

• SCR averages 0.75 ppmv over catalyst guarantee period

• SNCR averages 5 ppmv

• Note: actual NH3 slip data should be used if available

F2x = Technology Impact Factors, all that apply

ERSCR = [ EMSCR – ( Ks • B • fsreagent • SNH3 )] • F2 (AH) • F2 (PM) • 

ERSCR = ( 36 – ( 3799 * 8.95E-03 * 1 * 2 ))* 1 * 0.63 *

ERSCR = ( 36 – ( 6.80E+01 ))* 0.2961

ERSCR = -3.18E+01 * 0.2961

ERSCR = (9.42) Total H2SO4 released from SCR, lbs per hour

Equation 4-11b: Release

TSAR = ERComb + ERSCR/SNCR + ERFGC

TSAR = ERComb + ERSCR/SNCR + ERFGC

TSAR = 3.56 + (9.42) + 

TSAR = (5.86) Total H2SO4 released, lbs per hour

F2 (FGD)

0.47
Given/Assume

Combustion

Enter Value

C1 = 500 Coal burn, tons/hr

HV = 8,950 Btu/lb

S1 = 0.27 Coal sulfur weighted average, %

K2 = 0.875 0.95 for bituminous coals

0.875 for subbituminous coals

= 0.55 to 0.85 for lignite, based on the Na content

1.0 for oil

F1 = 0.0019 Fuel Impact Factor from F1 table

F2 (AH) = 0.36 Technology Impact Factor from F2 tables If not applicable, enter "1".

F2 (PM) = 0.72 Technology Impact Factor from F2 tables If not applicable, enter "1".

F2 (FGD) = 1 Technology Impact Factor from F2 tables If not applicable, enter "1".

For SCR

S2 = 0.005 SCR catalyst SO2 oxidation rate (specified as a decimal, typically from 0.001- 0.03)

fsops = 1 portion of time that SCR is in use

F2 (AH) = 1 Technology Impact Factor from F2 tables If not applicable, enter "1".

F2 (PM) = 0.63 Technology Impact Factor from F2 tables If not applicable, enter "1".

F2 (FGD) = 0.47 Technology Impact Factor from F2 tables If not applicable, enter "1".

F3SCR = 1 Technology Impact Factors for SCR

Coal Type F3SCR 

PRB 0.17

Other Coals 1 (no data available) 

fsreagent = 1 fraction of operation with reagent injection

SNH3 = 2 NH3 slip from SCR/SNCR, ppmv at 6% O2, wet
Equation 4-1 EMComb = K • F1 • E2

where,

EMComb= total H2SO4 manufactured from combustion, lbs/yr

K = Molecular weight and units conversion constant, equal to 3,063. 

This value is derived as follows: 98.07/64.04 • 2000 = 3,063. 

Here, 98.07 is the molecular weight of H2SO4; 64.04 is the molecular weight of SO2; conversion from tons per

year to pounds per year requires multiplying by 2000.

F1 = Fuel Impact Factor

E2 = Sulfur dioxide (SO2) emissions, either: (1) recorded by a continuous emissions monitor, tons/yr, or (2)

calculated from coal burn data, tons/yr.

When any source uses FGD equipment or another technology to control SO2 emissions, either the fuel basis must 

be used for the manufacturing and release calculations, or CEMS data can be used but only when the CEMS

precedes the FGD or SO2 control equipment. CEMS data after a flue gas desulfurization system cannot be

used.

As an alternative to using CEMS data, the following relationship based on coal burn data can be used to estimate

the rate of SO2 emissions:

Equation 4-2b E2 = K1 • K2 • C1 • S1

where,

E2 = SO2 mass rate, tons/yr

C1 = Coal burn, tons/yr

S1 = Coal sulfur weighted average, %

K1 = Molecular weight and units conversion constant, equal to 0.02. This value is derived from (64.04)/(100 •

32.06) = 0.02. Here, 64.04 is the molecular weight of SO2; 32.06 is the molecular weight of S; and conversion of %

S to a fraction requires multiplying by 100.

K2 = Sulfur conversion to SO2, implicit from EPA AP-42 (EPA, 1995b)

= 0.95 for bituminous coals

= 0.875 for subbituminous coals

= 0.55 to 0.85 for lignite, based on the Na content

= 1.0 for oil

Sulfuric Acid Released from Combustion (ERComb)

For units that do not employ SCR or SNCR NOx control or FGC, the sulfuric acid released is the product of the

amount manufactured and the Technology Impact Factors (F2) for all downstream equipment (the air heater, the

particulate control device, the FGD, etc.). For these units, the total sulfuric acid emissions can be calculated from

Equation 4-3.

Equation 4-3 ERComb = EMComb • F2 (all that apply)
Sulfuric Acid Manufacture by SCR (EMSCR)

The following relationship estimates the total H2SO4 manufactured from an SCR equipped utility boiler or steam

generator:

Equation 4-4 EMSCR = K • S2 • fsops • E2• F3SCR

where,

EMSCR = Total H2SO4 manufactured from SCR, lbs per year

K = Conversion factor = 3063

S2 = SCR catalyst SO2 oxidation rate (specified as a decimal, typically from 0.001-

0.03)

fsops = Operating factor of SCR system, or the fraction of coal burn when the flue gas is directed through the SCR,

whether NH3 reagent is injected to derive NOx reduction or not. This value should reflect the hours the SCR

reactor processed flue gas, which will be site-specific but can be approximated by generally 0.8 for year-round

peaking operation, 0.98 for year-round base-loaded operation, or 0.43 for seasonal operation

E2 = SO2 produced, tons per year

F3SCR = Technology Impact Factor, for SCR

An F3SCR factor for PRB coals is shown in Table 4-2. This factor is derived from measurements at two PRB-fired

units. SO3 emitted from these units was lower than specified in the catalyst guarantee, which was based on

laboratory test data. At present, there are no data to support F3SCR factors for other coals, so a factor of 1 (full

penetration) is recommended.

Table 4-2

F3SCR Technology Impact Factors for SCR

Coal Type F3SCR 

PRB 0.17

Other Coals 1 (no data available) 

Sulfuric Acid Released from SCR and SNCR

The sulfuric acid released from SCR or SNCR is determined by subtracting from the sulfuric acid manufactured the

amount removed by the residual ammonia, or ammonia slip. For SCR, the sulfuric acid released (ERSCR) is

estimated with the following relationship:

Equation 4-5 ERSCR = [EMSCR – (Ks • B • fsreagent • SNH3)] • F2x

where,

ERSCR = Total H2SO4 released from SCR, lbs per year
EMSCR = Total H2SO4 manufactured from SCR, lbs per year

Ks = Conversion factor = 3799

B = Coal burn in TBtu/yr

fsreagent = fraction of SCR operation with reagent injection, when residual NH3 is produced that will remove SO3.

The value of fsreagent will be similar to, but slightly less than, the value of fsops, defined for Equation 4-4.

SNH3 = NH3 slip from SCR/SNCR, ppmv at 6% O2, wet:

• SCR averages 0.75 ppmv over catalyst guarantee period

• SNCR averages 5 ppmv

• Note: actual NH3 slip data should be used if available

F2x = Technology Impact Factors, all that apply

The conversion factor Ks, equal to 3799, considers all relevant constants to yield the result in pounds per year of

sulfuric acid. The derivation of this constant, for the case where residual NH3 is reported in terms of 6% oxygen

and “wet” flue gas at 8.1% H2O, is presented in Text Box B.

The coal burn rate in TBtu/yr is obtained from coal use records, such as those reported to EIA in Form 767. The

operating factor of the SCR describes the portion of the coal burn that reflects the period of SCR operation, based

on whether the unit operates seasonally (0.43), annually in a base-load duty (0.98), or annually in peaking duty

(0.80).

Accordingly, total sulfuric acid manufacture (TSAM) and release (TSAR) is estimated for agenerating unit equipped

with SCR and flue gas conditioning by the following equations:

Equation 4-11a: Manufacture

TSAM = EMComb + EMSCR/SNCR + EMFGC

Equation 4-11b: Release

TSAR = ERComb + ERSCR/SNCR + ERFGC