Regulations last checked for updates: Jan 14, 2026
Title 40 - Protection of Environment last revised: Dec 31, 2026
§ 98.490 - Definition of the source category.
(a) A coke calciner is a process unit that heats petroleum coke to high temperatures for the purpose of removing impurities or volatile substances in the petroleum coke feedstock.
(b) This source category consists of rotary kilns, rotary hearth furnaces, or similar process units used to calcine petroleum coke and also includes afterburners or other emission control systems used to treat the coke calcining unit's process exhaust gas.
§ 98.491 - Reporting threshold.
You must report GHG emissions under this subpart if your facility contains a coke calciner and the facility meets the requirements of either § 98.2(a)(1) or (2).
§ 98.492 - GHGs to report.
You must report:
(a) CO2, CH4, and N2O emissions from each coke calcining unit under this subpart.
(b) CO2, CH4, and N2O emissions from auxiliary fuel used in the coke calcining unit and afterburner, if applicable, or other control system used to treat the coke calcining unit's process off-gas under subpart C of this part by following the requirements of subpart C.
§ 98.493 - Calculating GHG emissions.
(a) Calculate GHG emissions required to be reported in § 98.492(a) using the applicable methods in paragraph (b) of this section.
(b) For each coke calcining unit, calculate GHG emissions according to the applicable provisions in paragraphs (b)(1) through (4) of this section.
(1) If you operate and maintain a CEMS that measures CO2 emissions according to subpart C of this part, you must calculate and report CO2 emissions under this subpart by following the Tier 4 Calculation Methodology specified in § 98.33(a)(4) and all associated requirements for Tier 4 in subpart C of this part. Auxiliary fuel use CO2 emissions should be calculated in accordance with subpart C of this part and subtracted from the CO2 CEMS emissions to determine process CO2 emissions. Other coke calcining units must either install a CEMS that complies with the Tier 4 Calculation Methodology in subpart C of this part or follow the requirements of paragraph (b)(2) of this section.
(2) Calculate the CO2 emissions from the coke calcining unit using monthly measurements and equation 1 to this paragraph (b)(2).
Equation 1 to paragraph (b)(2)
Where:
CO2 = Annual CO2 emissions (metric tons CO2/year).
m = Month index.
Min,m = Mass of green coke fed to the coke calcining unit in month “m” from facility records (metric tons/year).
CCGC.m = Mass fraction carbon content of green coke fed to the coke calcining unit from facility measurement data in month “m” (metric ton carbon/metric ton green coke). If measurements are made more frequently than monthly, determine the monthly average as the arithmetic average for all measurements made during the calendar month.
Mout,m = Mass of marketable petroleum coke produced by the coke calcining unit in month “m” from facility records (metric tons petroleum coke/year).
Mdust,m = Mass of petroleum coke dust removed from the process through the dust collection system of the coke calcining unit in month “m” from facility records (metric ton petroleum coke dust/year). For coke calcining units that recycle the collected dust, the mass of coke dust removed from the process is the mass of coke dust collected less the mass of coke dust recycled to the process.
CCMPC,m = Mass fraction carbon content of marketable petroleum coke produced by the coke calcining unit in month “m” from facility measurement data (metric ton carbon/metric ton petroleum coke). If measurements are made more frequently than monthly, determine the monthly average as the arithmetic average for all measurements made during the calendar month.
44 = Molecular weight of CO2 (kg/kg-mole).
12 = Atomic weight of C (kg/kg-mole).
(3) Calculate CH4 emissions using equation 2 to this paragraph (b)(3).
Equation 2 to paragraph (b)(3)
Where:
CH4 = Annual methane emissions (metric tons CH4/year).
CO2 = Annual CO2 emissions calculated in paragraph (b)(1) or (2) of this section, as applicable (metric tons CO2/year).
EmF1 = Default CO2 emission factor for petroleum coke from table C-1 to subpart C of this part (kg CO2/MMBtu).
EmF2 = Default CH4 emission factor for “Petroleum Products (All fuel types in table C-1)” from table C-2 to subpart C of this part (kg CH4/MMBtu).
(4) Calculate N2O emissions using equation 3 to this paragraph (b)(4).
Equation 3 to paragraph (b)(4)
Where:
N2O = Annual nitrous oxide emissions (metric tons N2O/year).
CO2 = Annual CO2 emissions calculated in paragraph (b)(1) or (2) of this section, as applicable (metric tons CO2/year).
EmF1 = Default CO2 emission factor for petroleum coke from table C-1 to subpart C of this part (kg CO2/MMBtu).
EmF3 = Default N2O emission factor for “Petroleum Products (All fuel types in table C-1)” from table C-2 to subpart C of this part (kg N2O/MMBtu).
§ 98.494 - Monitoring and QA/QC requirements.
(a) Flow meters, gas composition monitors, and heating value monitors that are associated with sources that use a CEMS to measure CO2 emissions according to subpart C of this part or that are associated with stationary combustion sources must meet the applicable monitoring and QA/QC requirements in § 98.34.
(b) Determine the mass of petroleum coke monthly as required by equation 1 to § 98.493(b)(2) using mass measurement equipment meeting the requirements for commercial weighing equipment as described in NIST HB 44-2023 (incorporated by reference, see § 98.7). Calibrate the measurement device according to the procedures specified by NIST HB 44-2023 (incorporated by reference, see § 98.7) or the procedures specified by the manufacturer. Recalibrate either biennially or at the minimum frequency specified by the manufacturer.
(c) Determine the carbon content of petroleum coke as required by equation 1 § 98.493(b)(2) using any one of the following methods. Calibrate the measurement device according to procedures specified by the method or procedures specified by the measurement device manufacturer.
(1) ASTM D3176-15 (incorporated by reference, see § 98.7).
(2) ASTM D5291-16 (incorporated by reference, see § 98.7).
(3) ASTM D5373-21 (incorporated by reference, see § 98.7).
(d) The owner or operator must document the procedures used to ensure the accuracy of the monitoring systems used including but not limited to calibration of weighing equipment, flow meters, and other measurement devices. The estimated accuracy of measurements made with these devices must also be recorded.
§ 98.495 - Procedures for estimating missing data.
A complete record of all measured parameters used in the GHG emissions calculations is required (e.g., concentrations, flow rates, fuel heating values, carbon content values). Therefore, whenever a quality-assured value of a required parameter is unavailable (e.g., if a CEMS malfunctions during unit operation or if a required sample is not taken), a substitute data value for the missing parameter must be used in the calculations.
(a) For missing auxiliary fuel use data, use the missing data procedures in subpart C of this part.
(b) For each missing value of mass or carbon content of coke, substitute the arithmetic average of the quality-assured values of that parameter immediately preceding and immediately following the missing data incident. If the “after” value is not obtained by the end of the reporting year, you may use the “before” value for the missing data substitution. If, for a particular parameter, no quality-assured data are available prior to the missing data incident, the substitute data value must be the first quality-assured value obtained after the missing data period.
(c) For missing CEMS data, you must use the missing data procedures in § 98.35.
§ 98.496 - Data reporting requirements.
In addition to the reporting requirements of § 98.3(c), you must report the information specified in paragraphs (a) through (i) of this section for each coke calcining unit.
(a) The unit ID number (if applicable).
(b) Maximum rated throughput of the unit, in metric tons coke calcined/stream day.
(c) The calculated CO2, CH4, and N2O annual process emissions, expressed in metric tons of each pollutant emitted.
(d) A description of the method used to calculate the CO2 emissions for each unit (e.g., CEMS or equation 1 to § 98.493(b)(2)).
(e) Annual mass of green coke fed to the coke calcining unit from facility records (metric tons/year).
(f) Annual mass of marketable petroleum coke produced by the coke calcining unit from facility records (metric tons/year).
(g) Annual mass of petroleum coke dust removed from the process through the dust collection system of the coke calcining unit from facility records (metric tons/year) and an indication of whether coke dust is recycled to the unit (e.g., all dust is recycled, a portion of the dust is recycled, or none of the dust is recycled).
(h) Annual average mass fraction carbon content of green coke fed to the coke calcining unit from facility measurement data (metric tons C per metric ton green coke).
(i) Annual average mass fraction carbon content of marketable petroleum coke produced by the coke calcining unit from facility measurement data (metric tons C per metric ton petroleum coke).
§ 98.497 - Records that must be retained.
In addition to the records required by § 98.3(g), you must retain the records specified in paragraphs (a) and (b) of this section.
(a) The records of all parameters monitored under § 98.494.
(b) The applicable verification software records as identified in this paragraph (b). You must keep a record of the file generated by the verification software specified in § 98.5(b) for the applicable data specified in paragraphs (b)(1) through (5) of this section. Retention of this file satisfies the recordkeeping requirement for the data in paragraphs (b)(1) through (5) of this section.
(1) Monthly mass of green coke fed to the coke calcining unit from facility records (metric tons/year) (equation 1 to § 98.493(b)(2)).
(2) Monthly mass of marketable petroleum coke produced by the coke calcining unit from facility records (metric tons/year) (equation 1 to § 98.493(b)(2)).
(3) Monthly mass of petroleum coke dust removed from the process through the dust collection system of the coke calcining unit from facility records (metric tons/year) (equation 1 to § 98.493(b)(2)).
(4) Average monthly mass fraction carbon content of green coke fed to the coke calcining unit from facility measurement data (metric tons C per metric ton green coke) (equation 1 to § 98.493(b)(2)).
(5) Average monthly mass fraction carbon content of marketable petroleum coke produced by the coke calcining unit from facility measurement data (metric tons C per metric ton petroleum coke) (equation 1 to § 98.493(b)(2)).
§ 98.498 - Definitions.
All terms used in this subpart have the same meaning given in the Clean Air Act and subpart A of this part.
source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.
cite as: 40 CFR 98.493