Title 40

PART 75 APPENDIX F

Appendix F to Part 75 - Conversion Procedures

40:18.0.1.1.4.10.1.1.11 : Appendix F

Appendix F to Part 75 - Conversion Procedures 1. Applicability

Use the procedures in this appendix to convert measured data from a monitor or continuous emission monitoring system into the appropriate units of the standard.

2. Procedures for SO2 Emissions

Use the following procedures to compute hourly SO2 mass emission rate (in lb/hr) and quarterly and annual SO2 total mass emissions (in tons).

2.1 When measurements of SO2 concentration and flow rate are on a wet basis, use the following equation to compute hourly SO2 mass emission rate (in lb/hr):

Where: Eh = Hourly SO2 mass emission rate during unit operation, lb/hr. K = 1.660 × 10−7 for SO2, (lb/scf)/ppm. Ch = Hourly average SO2 concentration during unit operation, stack moisture basis, ppm. Qh = Hourly average volumetric flow rate during unit operation, stack moisture basis, scfh. 2.2 When measurements by the SO2 pollutant concentration monitor are on a dry basis and the flow rate monitor measurements are on a wet basis, use the following equation to compute hourly SO2 mass emission rate (in lb/hr):

where: Eh = Hourly SO2 mass emission rate during unit operation, lb/hr. K = 1.660 × 10−7 for SO2, (lb/scf)/ppm. Chp = Hourly average SO2 concentration during unit operation, ppm (dry). Qhs = Hourly average volumetric flow rate during unit operation, scfh as measured (wet). %H2O = Hourly average stack moisture content during unit operation, percent by volume.

2.3 Use the following equations to calculate total SO2 mass emissions for each calendar quarter (Equation F-3) and for each calendar year (Equation F-4), in tons:

(Eq. F-3) Where: Eq = Quarterly total SO2 mass emissions, tons. Eh = Hourly SO2 mass emission rate, lb/hr. th = Unit operating time, hour or fraction of an hour (in equal increments that can range from one hundredth to one quarter of an hour, at the option of the owner or operator). n = Number of hourly SO2 emissions values during calendar quarter. 2000 = Conversion of 2000 lb per ton.

Where: Ea = Annual total SO2 mass emissions, tons. Eq = Quarterly SO2 mass emissions, tons. q = Quarters for which Eq are available during calendar year.

2.4 Round all SO2 mass emission rates and totals to the nearest tenth.

3. Procedures for NOX Emission Rate

Use the following procedures to convert continuous emission monitoring system measurements of NOX concentration (ppm) and diluent concentration (percentage) into NOX emission rates (in lb/mmBtu). Perform measurements of NOX and diluent (O2 or CO2) concentrations on the same moisture (wet or dry) basis.

3.1 When the NOX continuous emission monitoring system uses O2 as the diluent, and measurements are performed on a dry basis, use the following conversion procedure:

(Eq. F-5) where, K, E, Ch, F, and %O2 are defined in section 3.3 of this appendix. When measurements are performed on a wet basis, use the equations in Method 19 in appendix A-7 to part 60 of this chapter.

3.2 When the NOX continuous emission monitoring system uses CO2 as the diluent, use the following conversion procedure:

(Eq. F-6) where: K, E, Ch, Fc, and %CO2 are defined in section 3.3 of this appendix. When CO2 and NOX measurements are performed on a different moisture basis, use the equations in Method 19 in appendix A-7 to part 60 of this chapter.

3.3 Use the definitions listed below to derive values for the parameters in equations F-5 and F-6 of this appendix, or (if applicable) in the equations in Method 19 in appendix A-7 to part 60 of this chapter.

3.3.1 K = 1.194 × 10−7 (lb/dscf)/ppm NOX.

3.3.2 E = Pollutant emissions during unit operation, lb/mmBtu.

3.3.3 Ch = Hourly average pollutant concentration during unit operation, ppm.

3.3.4 %O2, %CO2 = Oxygen or carbon dioxide volume during unit operation (expressed as percent O2 or CO2).

3.3.4.1 For boilers, a minimum concentration of 5.0 percent CO2 or a maximum concentration of 14.0 percent O2 may be substituted for the measured diluent gas concentration value for any operating hour in which the hourly average CO2 concentration is <5.0 percent CO2 or the hourly average O2 concentration is >14.0 percent O2. For stationary gas turbines, a minimum concentration of 1.0 percent CO2 or a maximum concentration of 19.0 percent O2 may be substituted for measured diluent gas concentration values for any operating hour in which the hourly average CO2 concentration is <1.0 percent CO2 or the hourly average O2 concentration is >19.0 percent O2.

3.3.4.2 If NOX emission rate is calculated using either Equation 19-3 or 19-5 in Method 19 in appendix A-7 to part 60 of this chapter, a variant of the equation shall be used whenever the diluent cap is applied. The modified equations shall be designated as Equations 19-3D and 19-5D, respectively. Equation 19-3D is structurally the same as Equation 19-3, except that the term “%O2w” in the denominator is replaced with the term “%O2dc × [(100−% H2O)/100]”, where %O2dc is the diluent cap value. The numerator of Equation 19-5D is the same as Equation 19-5; however, the denominator of Equation 19-5D is simply “20.9−%O2dc”, where %O2dc is the diluent cap value.

3.3.5 F, Fc = a factor representing a ratio of the volume of dry flue gases generated to the caloric value of the fuel combusted (F), and a factor representing a ratio of the volume of CO2 generated to the calorific value of the fuel combusted (Fc), respectively. Table 1 lists the values of F and Fc for different fuels.

Table 1 - F- and Fc-Factors ¹

Fuel	F-factor (dscf/mmBtu)	FC-factor (scf CO2/mmBtu)
Coal (as defined by ASTM D388-99 ²):
Anthracite	10,100	1,970
Bituminous	9,780	1,800
Subbituminous	9,820	1,840
Lignite	9,860	1,910
Petroleum Coke	9,830	1,850
Tire Derived Fuel	10,260	1,800
Oil	9,190	1,420
Gas:
Natural gas	8,710	1,040
Propane	8,710	1,190
Butane	8,710	1,250
Wood:
Bark	9,600	1,920
Wood residue	9,240	1,830

3.3.6 Equations F-7a and F-7b may be used in lieu of the F or Fc factors specified in Section 3.3.5 of this appendix to calculate a site-specific dry-basis F factor (dscf/mmBtu) or a site-specific Fc factor (scf CO2/mmBtu), on either a dry or wet basis. At a minimum, the site-specific F or Fc factor must be based on 9 samples of the fuel. Fuel samples taken during each run of a RATA are acceptable for this purpose. The site-specific F or Fc factor must be re-determined at least annually, and the value from the most recent determination must be used in the emission calculations. Alternatively, the previous F or Fc value may continue to be used if it is higher than the value obtained in the most recent determination. The owner or operator shall keep records of all site-specific F or Fc determinations, active for at least 3 years. (Calculate all F- and Fc factors at standard conditions of 20 °C (68 °F) and 29.92 inches of mercury).

3.3.6.1 H, C, S, N, and O are content by weight of hydrogen, carbon, sulfur, nitrogen, and oxygen (expressed as percent), respectively, as determined on the same basis as the gross calorific value (GCV) by ultimate analysis of the fuel combusted using ASTM D3176-89 (Reapproved 2002), Standard Practice for Ultimate Analysis of Coal and Coke, (solid fuels), ASTM D5291-02, Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants, (liquid fuels) or computed from results using ASTM D1945-96 (Reapproved 2001), Standard Test Method for Analysis of Natural Gas by Gas Chromatography, or ASTM D1946-90 (Reapproved 2006), Standard Practice for Analysis of Reformed Gas by Gas Chromatography, (gaseous fuels) as applicable. (All of these methods are incorporated by reference under § 75.6 of this part.)

3.3.6.2 GCV is the gross calorific value (Btu/lb) of the fuel combusted determined by ASTM D5865-01a or ASTM D5865-10, ASTM D240-00 or ASTM D4809-00, and ASTM D3588-98, ASTM D4891-89 (Reapproved 2006), GPA Standard 2172-96, GPA Standard 2261-00, or ASTM D1826-94 (Reapproved 1998), as applicable. (All of these methods are incorporated by reference under § 75.6.)

3.3.6.3 For affected units that combust a combination of a fuel (or fuels) listed in Table 1 in section 3.3.5 of this appendix with any fuel(s) not listed in Table 1, the F or Fc value is subject to the Administrator's approval under § 75.66.

3.3.6.4 For affected units that combust combinations of fuels listed in Table 1 in section 3.3.5 of this appendix, prorate the F or Fc factors determined by section 3.3.5 or 3.3.6 of this appendix in accordance with the applicable formula as follows:

3.3.6.5 As an alternative to prorating the F or Fc factor as described in section 3.3.6.4 of this appendix, a “worst-case” F or Fc factor may be reported for any unit operating hour. The worst-case F or Fc factor shall be the highest F or Fc value for any of the fuels combusted in the unit.

3.4 Use the following equations to calculate the average NOX emission rate for each calendar quarter (Equation F-9) and the average emission rate for the calendar year (Equation F-10), in lb/mmBtu:

Use the following procedures to convert continuous emission monitoring system measurements of CO2 concentration (percentage) and volumetric flow rate (scfh) into CO2 mass emissions (in tons/day) when the owner or operator uses a CO2 continuous emission monitoring system (consisting of a CO2 or O2 pollutant monitor) and a flow monitoring system to monitor CO2 emissions from an affected unit.

4.1 When CO2 concentration is measured on a wet basis, use the following equation to calculate hourly CO2 mass emissions rates (in tons/hr):

4.2 When CO2 concentration is measured on a dry basis, use Equation F-2 to calculate the hourly CO2 mass emission rate (in tons/hr) with a K-value of 5.7 × 10−7 (tons/scf) percent CO2, where Eh = hourly CO2 mass emission rate, tons/hr and Chp = hourly average CO2 concentration in flue, dry basis, percent CO2.

4.3 Use the following equations to calculate total CO2 mass emissions for each calendar quarter (Equation F-12) and for each calendar year (Equation F-13):

4.4 For an affected unit, when the owner or operator is continuously monitoring O2 concentration (in percent by volume) of flue gases using an O2 monitor, use the equations and procedures in section 4.4.1 and 4.4.2 of this appendix to determine hourly CO2 mass emissions (in tons).

4.4.1 If the owner or operator elects to use data from an O2 monitor to calculate CO2 concentration, the appropriate F and FC factors from section 3.3.5 of this appendix shall be used in one of the following equations (as applicable) to determine hourly average CO2 concentration of flue gases (in percent by volume) from the measured hourly average O2 concentration:

For any hour where Equation F-14a or F-14b results in a negative hourly average CO2 value, 0.0% CO2w shall be recorded as the average CO2 value for that hour.

4.4.2 Determine CO2 mass emissions (in tons) from hourly average CO2 concentration (percent by volume) using equation F-11 and the procedure in section 4.1, where O2 measurements are on a wet basis, or using the procedures in section 4.2 of this appendix, where O2 measurements are on a dry basis.

Use the following procedures to compute heat input rate to an affected unit (in mmBtu/hr or mmBtu/day):

5.1 Calculate and record heat input rate to an affected unit on an hourly basis, except as provided in sections 5.5 through 5.5.7. The owner or operator may choose to use the provisions specified in § 75.16(e) or in section 2.1.2 of appendix D to this part in conjunction with the procedures provided in sections 5.6 through 5.6.2 to apportion heat input among each unit using the common stack or common pipe header.

5.2 For an affected unit that has a flow monitor (or approved alternate monitoring system under subpart E of this part for measuring volumetric flow rate) and a diluent gas (O2 or CO2) monitor, use the recorded data from these monitors and one of the following equations to calculate hourly heat input rate (in mmBtu/hr).

5.2.1 When measurements of CO2 concentration are on a wet basis, use the following equation:

5.2.2 When measurements of CO2 concentration are on a dry basis, use the following equation:

5.2.3 When measurements of O2 concentration are on a wet basis, use the following equation:

5.2.4 When measurements of O2 concentration are on a dry basis, use the following equation:

5.3.1 Calculate total quarterly heat input for a unit or common stack using a flow monitor and diluent monitor to calculate heat input, using the following equation:

5.3.2 Calculate total cumulative heat input for a unit or common stack using a flow monitor and diluent monitor to calculate heat input, using the following equation:

5.5 For a gas-fired or oil-fired unit that does not have a flow monitor and is using the procedures specified in appendix D to this part to monitor SO2 emissions or for any unit using a common stack for which the owner or operator chooses to determine heat input by fuel sampling and analysis, use the following procedures to calculate hourly heat input rate in mmBtu/hr. The procedures of section 5.5.3 of this appendix shall not be used to determine heat input from a coal unit that is required to comply with the provisions of this part for monitoring, recording, and reporting NOX mass emissions under a State or federal NOX mass emission reduction program.

5.5.1 (a) When the unit is combusting oil, use the following equation to calculate hourly heat input rate:

(b) When performing oil sampling and analysis solely for the purpose of the missing data procedures in § 75.36, oil samples for measuring GCV may be taken weekly, and the procedures specified in appendix D to this part for determining the mass rate of oil consumed per hour are optional.

5.5.2 When the unit is combusting gaseous fuels, use the following equation to calculate heat input rate from gaseous fuels for each hour:

5.5.3 When the unit is combusting coal, use the procedures, methods, and equations in sections 5.5.3.1-5.5.3.3 of this appendix to determine the heat input from coal for each 24-hour period. (All ASTM methods are incorporated by reference under § 75.6 of this part.)

5.5.3.1 Perform coal sampling daily according to section 5.3.2.2 in Method 19 in appendix A to part 60 of this chapter and use ASTM D2234-00, Standard Practice for Collection of a Gross Sample of Coal, (incorporated by reference under § 75.6 of this part) Type I, Conditions A, B, or C and systematic spacing for sampling. (When performing coal sampling solely for the purposes of the missing data procedures in § 75.36, use of ASTM D2234-00 is optional, and coal samples may be taken weekly.)

5.5.3.2 All ASTM methods are incorporated by reference under § 75.6. Use ASTM D2013-01 for preparation of a daily coal sample and analyze each daily coal sample for gross calorific value using ASTM D5865-01a or ASTM D5865-10. On-line coal analysis may also be used if the on-line analytical instrument has been demonstrated to be equivalent to the applicable ASTM methods under §§ 75.23 and 75.66.

5.5.4 For units obtaining heat input values daily instead of hourly, apportion the daily heat input using the fraction of the daily steam load or daily unit operating load used each hour in order to obtain HIi for use in the above equations. Alternatively, use the hourly mass of coal consumed in equation F-21.

5.5.5 If a daily fuel sampling value for gross calorific value is not available, substitute the maximum gross calorific value measured from the previous 30 daily samples. If a monthly fuel sampling value for gross calorific value is not available, substitute the maximum gross calorific value measured from the previous 3 monthly samples.

5.5.6 If a fuel flow value is not available, use the fuel flowmeter missing data procedures in section 2.4 of appendix D of this part. If a daily coal consumption value is not available, substitute the maximum fuel feed rate during the previous thirty days when the unit burned coal.

5.5.7 Results for samples must be available no later than thirty calendar days after the sample is composited or taken. However, during an audit, the Administrator may require that the results be available in five business days, or sooner if practicable.

5.6.1 Where applicable, the owner or operator of an affected unit that determines heat input rate at the unit level by apportioning the heat input monitored at a common stack or common pipe using megawatts shall apportion the heat input rate using the following equation:

5.6.2 Where applicable, the owner or operator of an affected unit that determines the heat input rate at the unit level by apportioning the heat input rate monitored at a common stack or common pipe using steam load shall apportion the heat input rate using the following equation:

The owner or operator of an affected unit that determines the heat input rate at the unit level by summing the heat input rates monitored at multiple stacks or multiple pipes shall sum the heat input rates using the following equation:

As an alternative to using Equation F-21a or F-21b in section 5.6 of this appendix, the owner or operator may apportion the heat input rate at a common pipe to the individual units served by the common pipe based on the fuel flow rate to the individual units, as measured by uncertified fuel flowmeters. This option may only be used if a fuel flowmeter system that meets the requirements of appendix D to this part is installed on the common pipe. If this option is used, determine the unit heat input rates using the following equation:

Use the following equation to convert volumetric flow at actual temperature and pressure to standard temperature and pressure.

The owner or operator shall use Equation F-23 to calculate hourly SO2 mass emissions in accordance with § 75.11(e)(1) during the combustion of gaseous fuel, for a unit that uses a flow monitor and a diluent gas monitor to measure heat input, and that qualifies to use a default SO2 emission rate under section 2.3.1.1, 2.3.2.1.1, or 2.3.6(b) of appendix D to this part. Equation F-23 may also be applied to the combustion of solid or liquid fuel that meets the definition of very low sulfur fuel in § 72.2 of this chapter, combinations of such fuels, or mixtures of such fuels with gaseous fuel, if the owner or operator has received approval from the Administrator under § 75.66 to use a site-specific default SO2 emission rate for the fuel or mixture of fuels.

The owner or operator of a unit that is required to monitor, record, and report NOX mass emissions under a State or federal NOX mass emission reduction program must use the procedures in section 8.1, 8.2, or 8.3 of this appendix, as applicable, to account for hourly NOX mass emissions, and the procedures in section 8.4 of this appendix to account for quarterly, seasonal, and annual NOX mass emissions to the extent that the provisions of subpart H of this part are adopted as requirements under such a program.

8.1 The owner or operator may use the hourly NOX emission rate and the hourly heat input rate to calculate the NOX mass emissions in pounds or the NOX mass emission rate in pounds per hour, (as required by the applicable reporting format), for each unit or stack operating hour, as follows:

8.1.1 If both NOX emission rate and heat input rate are monitored at the same unit or stack level (e.g., the NOX emission rate value and the heat input rate value both represent all of the units exhausting to the common stack), then (as required by the applicable reporting format) either:

8.1.2 If NOX emission rate is measured at a common stack and heat input is measured at the unit level, sum the hourly heat inputs at the unit level according to the following formula:

8.1.3 If a unit has multiple ducts and NOX emission rate is only measured at one duct, use the NOX emission rate measured at the duct, the heat input measured for the unit, and the procedures in section 8.1.1 of this appendix to determine NOX mass emissions.

8.1.4 If a unit has multiple ducts and NOX emission rate is measured in each duct, heat input shall also be measured in each duct and the procedures in section 8.1.1 of this appendix shall be used to determine NOX mass emissions.

8.2 Alternatively, the owner or operator may use the hourly NOX concentration (as measured by a NOX concentration monitoring system) and the hourly stack gas volumetric flow rate to calculate the NOX mass emission rate (lb/hr) for each unit or stack operating hour, in accordance with section 8.2.1 or 8.2.2 of this appendix (as applicable). If the hourly NOX mass emissions are to be reported in lb, Equation F-26c in section 8.3 of this appendix shall be used to convert the hourly NOX mass emission rates to hourly NOX mass emissions (lb).

8.2.1 When the NOX concentration monitoring system measures on a wet basis, first calculate the hourly NOX mass emission rate (in lb/hr) during unit (or stack) operation, using Equation F-26a. (Include bias-adjusted flow rate or NOX concentration values, where the bias-test procedures in appendix A to this part shows a bias-adjustment factor is necessary.)

8.2.2 When NOX mass emissions are determined using a dry basis NOX concentration monitoring system and a wet basis flow monitoring system, first calculate hourly NOX mass emission rate (in lb/hr) during unit (or stack) operation, using Equation F-26b. (Include bias-adjusted flow rate or NOX concentration values, where the bias-test procedures in appendix A to this part shows a bias-adjustment factor is necessary.)

8.3 When hourly NOX mass emissions are reported in pounds and are determined using a NOX concentration monitoring system and a flow monitoring system, calculate NOX mass emissions (lb) for each unit or stack operating hour by multiplying the hourly NOX mass emission rate (lb/hr) by the unit operating time for the hour, as follows:

8.4 Use the following procedures to calculate quarterly, cumulative ozone season, and cumulative yearly NOX mass emissions, in tons:

8.5 Specific provisions for monitoring NOX mass emissions from common stacks. The owner or operator of a unit utilizing a common stack may account for NOX mass emissions using either of the following methodologies, if the provisions of subpart H are adopted as requirements of a State or federal NOX mass reduction program:

8.5.1 The owner or operator may determine both NOX emission rate and heat input at the common stack and use the procedures in section 8.1.1 of this appendix to determine hourly NOX mass emissions at the common stack.

8.5.2 The owner or operator may determine the NOX emission rate at the common stack and the heat input at each of the units and use the procedures in section 8.1.2 of this appendix to determine the hourly NOX mass emissions at each unit.

If a correction for the stack gas moisture content is required in any of the emissions or heat input calculations described in this appendix, and if the hourly moisture content is determined from wet- and dry-basis O2 readings, use Equation F-31 to calculate the percent moisture, unless a “K” factor or other mathematical algorithm is developed as described in section 6.5.7(a) of appendix A to this part: