§ 98.173
Calculating GHG emissions.
You must calculate and report the annual process CO2 emissions from each taconite indurating furnace, basic oxygen furnace, non-recovery coke oven battery, sinter process, EAF, decarburization vessel, and direct reduction furnace using the procedures in either paragraph (a) or (b) of this section. Calculate and report the annual process CO2 emissions from the coke pushing process according to paragraph (c) of this section.

(a) Calculate and report under this subpart the process CO2 emissions by operating and maintaining CEMS according to the Tier 4 Calculation Methodology in § 98.33(a)(4) and all associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).

(b) Calculate and report under this subpart the process CO2 emissions using the procedure in paragraph (b)(1) or (b)(2) of this section.

(1) Carbon mass balance method. Calculate the annual mass emissions of CO2 for the process as specified in paragraphs (b)(1)(i) through (b)(1)(vii) of this section. The calculations are based on the annual mass of inputs and outputs to the process and an annual analysis of the respective weight fraction of carbon as determined according to the procedures in § 98.174(b). If you have a process input or output other than CO2 in the exhaust gas that contains carbon that is not included in Equations Q-1 through Q-7 of this section, you must account for the carbon and mass rate of that process input or output in your calculations according to the procedures in § 98.174(b)(5).

(i) For taconite indurating furnaces, estimate CO2 emissions using Equation Q-1 of this section.

$ER30OC09.063$
Where:
CO2 = Annual CO2 mass emissions from the taconite indurating furnace (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Fs) = Annual mass of the solid fuel used (metric tons).
(Csf) = Carbon content of the solid fuel, from the fuel analysis (expressed as a decimal fraction).
(Fg) = Annual volume of the gaseous fuel used (scf).
(Cgf) = Average carbon content of the gaseous fuel, from the fuel analysis results (kg C per kg of fuel).
MW = Molecular weight of the gaseous fuel (kg/kg-mole).
MVC = Molar volume conversion factor (849.5 scf per kg-mole at standard conditions).
0.001 = Conversion factor from kg to metric tons.
(Fl) = Annual volume of the liquid fuel used (gallons).
(Clf) = Carbon content of the liquid fuel, from the fuel analysis results (kg C per gallon of fuel).
(O) = Annual mass of greenball (taconite) pellets fed to the furnace (metric tons).
(C0) = Carbon content of the greenball (taconite) pellets, from the carbon analysis results (expressed as a decimal fraction).
(P) = Annual mass of fired pellets produced by the furnace (metric tons).
(Cp) = Carbon content of the fired pellets, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(ii) For basic oxygen process furnaces, estimate CO2 emissions using Equation Q-2 of this section.

$ER30OC09.064$
Where:
CO2 = Annual CO2 mass emissions from the basic oxygen furnace (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Iron) = Annual mass of molten iron charged to the furnace (metric tons).
(CIron) = Carbon content of the molten iron, from the carbon analysis results (expressed as a decimal fraction).
(Scrap) = Annual mass of ferrous scrap charged to the furnace (metric tons).
(CScrap) = Carbon content of the ferrous scrap, from the carbon analysis results (expressed as a decimal fraction).
(Flux) = Annual mass of flux materials (e.g., limestone, dolomite) charged to the furnace (metric tons).
(CFlux) = Carbon content of the flux materials, from the carbon analysis results (expressed as a decimal fraction).
(Carbon) = Annual mass of carbonaceous materials (e.g., coal, coke) charged to the furnace (metric tons).
(CCarbon) = Carbon content of the carbonaceous materials, from the carbon analysis results (expressed as a decimal fraction).
(Steel) = Annual mass of molten raw steel produced by the furnace (metric tons).
(CSteel) = Carbon content of the steel, from the carbon analysis results (expressed as a decimal fraction).
(Slag) = Annual mass of slag produced by the furnace (metric tons).
(CSlag) = Carbon content of the slag, from the carbon analysis (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction),
(iii) For non-recovery coke oven batteries, estimate CO2 emissions using Equation Q-3 of this section.

$ER30OC09.065$
Where:
CO2 = Annual CO2 mass emissions from the non-recovery coke oven battery (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Coal) = Annual mass of coal charged to the battery (metric tons).
(CCoal) = Carbon content of the coal, from the carbon analysis results (expressed as a decimal fraction).
(Coke) = Annual mass of coke produced by the battery (metric tons).
(CCoke) = Carbon content of the coke, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(iv) For sinter processes, estimate CO2 emissions using Equation Q-4 of this section.

$ER30OC09.066$
Where:
CO2 = Annual CO2 mass emissions from the sinter process (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Fg) = Annual volume of the gaseous fuel used (scf).
(Cgf) = Carbon content of the gaseous fuel, from the fuel analysis results (kg C per kg of fuel).
MW = Molecular weight of the gaseous fuel (kg/kg-mole).
MVC = Molar volume conversion factor (849.5 scf per kg-mole at standard conditions).
0.001 = Conversion factor from kg to metric tons.
(Feed) = Annual mass of sinter feed material (metric tons).
(CFeed) = Carbon content of the mixed sinter feed materials that form the bed entering the sintering machine, from the carbon analysis results (expressed as a decimal fraction).
(Sinter) = Annual mass of sinter produced (metric tons).
(CSinter) = Carbon content of the sinter pellets, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(v) For EAFs, estimate CO2 emissions using Equation Q-5 of this section.

ER09DE16.004
Where:
CO2 = Annual CO2 mass emissions from the EAF (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Iron) = Annual mass of direct reduced iron (if any) charged to the furnace (metric tons).
(CIron) = Carbon content of the direct reduced iron, from the carbon analysis results (expressed as a decimal fraction).
(Scrap) = Annual mass of ferrous scrap charged to the furnace (metric tons).
(CScrap) = Carbon content of the ferrous scrap, from the carbon analysis results (expressed as a decimal fraction).
(Flux) = Annual mass of flux materials (e.g., limestone, dolomite) charged to the furnace (metric tons).
(CFlux) = Carbon content of the flux materials, from the carbon analysis results (expressed as a decimal fraction).
(Electrode) = Annual mass of carbon electrode consumed (metric tons).
(CElectrode) = Carbon content of the carbon electrode, from the carbon analysis results (expressed as a decimal fraction).
(Carbon) = Annual mass of carbonaceous materials (e.g., coal, coke) charged to the furnace (metric tons).
(CCarbon) = Carbon content of the carbonaceous materials, from the carbon analysis results (expressed as a decimal fraction).
(Steel) = Annual mass of molten raw steel produced by the furnace (metric tons).
(CSteel) = Carbon content of the steel, from the carbon analysis results (expressed as a decimal fraction).
(Fg) = Annual volume of the gaseous fuel used (scf at 60 degrees F and one atmosphere).
(Cgf) = Average carbon content of the gaseous fuel, from the fuel analysis results (kg C per kg of fuel).
(MW) = Molecular weight of the gaseous fuel (kg/kg-mole).
(MVC) = Molar volume conversion factor (836.6 scf per kg-mole at standard conditions of 60 degrees F and one atmosphere).
(0.001) = Conversion factor from kg to metric tons.
(Slag) = Annual mass of slag produced by the furnace (metric tons).
(CSlag) = Carbon content of the slag, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(vi) For decarburization vessels, estimate CO2 emissions using Equation Q-6 of this section.

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Where:
CO2 = Annual CO2 mass emissions from the decarburization vessel (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Steel) = Annual mass of molten steel charged to the vessel (metric tons).
(CSteelin) = Carbon content of the molten steel before decarburization, from the carbon analysis results (expressed as a decimal fraction).
(CSteelout) = Carbon content of the molten steel after decarburization, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(vii) For direct reduction furnaces, estimate CO2 emissions using Equation Q-7 of this section.

$ER30OC09.069$
Where:
CO2 = Annual CO2 mass emissions from the direct reduction furnace (metric tons).
44/12 = Ratio of molecular weights, CO2 to carbon.
(Fg) = Annual volume of the gaseous fuel used (scf).
(Cgf) = Carbon content of the gaseous fuel, from the fuel analysis results (kg C per kg of fuel).
MW = Molecular weight of the gaseous fuel (kg/kg-mole).
MVC = Molar volume conversion factor (849.5 scf per kg-mole at standard conditions).
0.001 = Conversion factor from kg to metric tons.
(Ore) = Annual mass of iron ore or iron ore pellets fed to the furnace (metric tons).
(COre) = Carbon content of the iron ore or iron ore pellets, from the carbon analysis results (expressed as a decimal fraction).
(Carbon) = Annual mass of carbonaceous materials (e.g., coal, coke) charged to the furnace (metric tons).
(CCarbon) = Carbon content of the carbonaceous materials, from the carbon analysis results (expressed as a decimal fraction).
(Other) = Annual mass of other materials charged to the furnace (metric tons).
(COther) = Average carbon content of the other materials charged to the furnace, from the carbon analysis results (expressed as a decimal fraction).
(Iron) = Annual mass of iron produced (metric tons).
(CIron) = Carbon content of the iron, from the carbon analysis results (expressed as a decimal fraction).
(NM) = Annual mass of non-metallic materials produced by the furnace (metric tons).
(CNM) = Carbon content of the non-metallic materials, from the carbon analysis results (expressed as a decimal fraction).
(R) = Annual mass of air pollution control residue collected (metric tons).
(CR) = Carbon content of the air pollution control residue, from the carbon analysis results (expressed as a decimal fraction).
(2) Site-specific emission factor method. Conduct a performance test and measure CO2 emissions from all exhaust stacks for the process and measure either the feed rate of materials into the process or the production rate during the test as described in paragraphs (b)(2)(i) through (b)(2)(iv) of this section.

(i) You must measure the process production rate or process feed rate, as applicable, during the performance test according to the procedures in § 98.174(c)(5) and calculate the average rate for the test period in metric tons per hour.

(ii) You must calculate the hourly CO2 emission rate using Equation Q-8 of this section and determine the average hourly CO2 emission rate for the test.

$ER30OC09.070$
Where:
CO2 = CO2 mass emission rate, corrected for moisture (metric tons/hr).
5.18 × 10−7 = Conversion factor (metric tons/scf−% CO2).
CCO2 = Hourly CO2 concentration, dry basis (% CO2).
Q = Hourly stack gas volumetric flow rate (scfh).
%H2O = Hourly moisture percentage in the stack gas.
(iii) You must calculate a site-specific emission factor for the process in metric tons of CO2 per metric ton of feed or production, as applicable, by dividing the average hourly CO2 emission rate during the test by the average hourly feed or production rate during the test.

(iv) You must calculate CO2 emissions for the process by multiplying the emission factor by the total amount of feed or production, as applicable, for the reporting period.

(c) You must determine emissions of CO2 from the coke pushing process in mtCO2e by multiplying the metric tons of coal charged to the by-product recovery and non-recovery coke ovens during the reporting period by 0.008.

(d) If GHG emissions from a taconite indurating furnace, basic oxygen furnace, non-recovery coke oven battery, sinter process, EAF, decarburization vessel, or direct reduction furnace are vented through a stack equipped with a CEMS that complies with the Tier 4 methodology in subpart C of this part, or through the same stack as any combustion unit or process equipment that reports CO2 emissions using a CEMS that complies with the Tier 4 Calculation Methodology in subpart C of this part (General Stationary Fuel Combustion Sources), then the calculation methodology in paragraph (b) of this section shall not be used to calculate process emissions. The owner or operator shall report under this subpart the combined stack emissions according to the Tier 4 Calculation Methodology in § 98.33(a)(4) and comply with all associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources).

[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 66464, Oct. 28, 2010; 78 FR 71956, Nov. 29, 2013; 81 FR 89258, Dec. 9, 2016]