Flare emissions from the gas composition
CO₂ from the carbon balance with the oxidation factor, unburnt methane and hydrocarbons, SO₂ from hydrogen sulphide and the CO₂ equivalent, from the volume of gas burnt and its composition. With OF = 1: complete combustion in furnaces, boilers and turbines.
n = V / V_m, V_m = 24.055 m³/kmol (20 °C)CO₂ = n · (OF · Σ c_i · y_i + y_CO₂) · 44.01CH₄ = n · (1 − OF) · y_CH₄ · 16.043SO₂ = n · OF · y_H₂S · 64.064CO₂e = CO₂ + GWP · CH₄The oxidation factor of 0.995 for flares and 1 for heat generation follows the methodology for greenhouse gas emissions from combustible gases (Order No. 9, para 9) and the oil and gas production methodology (para 22). For reporting, the CO₂ factor from the gas composition is calculated with the electronic tool of the carbon trading system operator; here the CO₂ contained in the gas is not multiplied by OF because it does not oxidize (a difference of hundredths of a percent). The unburnt share 1 − OF is assigned to the original gas components, an upper estimate of methane; under para 26 of the methodology the residual methane and N₂O of flares are normally not counted. Pollutants for permits and payments (CO, NO₂, soot, hydrocarbons) are calculated with the flare emission methodology, where unburnt losses depend on smokeless or sooting combustion. Ideal gas, 20 °C and 101.325 kPa.
Source: Order No. 9 of 17.01.2023: methodologies for greenhouse gas emissions from combustible gases (paras 6–10) and from oil and gas production (paras 22, 26); combustion stoichiometry
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
At standard conditions (20 °C, 101.325 kPa), from the flare gas meter.
Mole (volume) % from a chromatographic analysis. If the sum is below 100 % the rest counts as ethane (para 7 of Methodology No. 9); above 100 % the composition is normalized.
Counted as pentane C₅H₁₂.
Burnt hydrogen sulphide turns into SO₂: 1.88 t SO₂ per t H₂S.
0.995 for flaring, 1 for combustion to produce heat (Methodology No. 9, para 9).
IPCC AR5: 28, the default (national inventory under the Paris Agreement); AR4: 25; AR6 (fossil methane): 29.8.
Unit converter for this formulaGas volume · Mass · Density and °API · Fraction and percent
- Sm³ (20 °C)1
- 10³ Sm³0.001
- 10⁶ Sm³1·10⁻⁶
- 10⁹ Sm³1·10⁻⁹
- Sm³ (15 °C)0.982944
- Nm³ (0 °C)0.931776
- scf34.7793
- Mscf0.0347793
- MMscf3.47793·10⁻⁵
- Bcf3.47793·10⁻⁸
Gas at standard conditions, 101.325 kPa: Sm³ at 20 °C (GOST 2939, used in Kazakhstan), Sm³ (15 °C) per ISO 13443 and SPE, Nm³ at 0 °C, scf at 60 °F. Gas volumes convert by the ideal-gas law, so 1 Sm³ = 34.78 scf (not 35.31 as for a geometric volume).
- CH₄ — Unburnt methane–
- C₂₊ — Unburnt C₂₊ hydrocarbons (excluding methane)–
- SO₂ — Sulphur dioxide–
- H₂S — Unburnt hydrogen sulphide–
- CO₂e — CO₂ equivalent (CO₂ and unburnt methane)–
- m — Mass of gas burnt–
- ρ — Gas density at 20 °C–
- EF — CO₂ emission factor per volume of gas–t CO₂/10³ m³
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.