10.11.2022
EN
Official Journal of the European Union
L 290/413
If RfCH4 < 1.05, it may be omitted from the equation above for CCH4.
In case (b), the concentration of CH4 and NMHC shall be calculated using the following equations:
CCH4 ¼
CNMHC ¼
CHCðw=NMCÞ Ü RfCH4 Ü ð1 Ä EM Þ Ä CHCðw=oNMCÞ Ü ð1 Ä EE Þ RfCH4 Ü ðEE Ä EM Þ
CHCðw=oNMCÞ Ü ð1 Ä EM Þ Ä CHCðw=NMCÞ Ü RfCH4 Ü ð1 Ä EM Þ EE Ä EM
where: CHC(w/NMC)
is the HC concentration with sample gas flowing through the NMC, ppm C;
CHC(w/oNMC)
is the HC concentration with sample gas bypassing the NMC, ppm C;
RfCH4
is the methane response factor as determined per paragraph 5.4.3.2. of Annex B5;
EM
is the methane efficiency as determined per paragraph 3.2.1.1.3.3.1. of this annex;
EE
is the ethane efficiency as determined per paragraph 3.2.1.1.3.3.2. of this annex.
If RfCH4 < 1.05, it may be omitted in the equations for case (b) above for CCH4 and CNMHC.
3.2.1.1.3.3.
Conversion efficiencies of the non-methane cutter, NMC The NMC is used for the removal of the non-methane hydrocarbons from the sample gas by oxidizing all hydrocarbons except methane.
Ideally, the conversion for methane is 0 per cent, and for the other hydrocarbons represented by ethane is 100 per cent.
For the accurate measurement of NMHC, the two efficiencies shall be determined and used for the calculation of the NMHC emission.
3.2.1.1.3.3.1.
Methane conversion efficiency, EM The methane/air calibration gas shall be flowed to the FID through the NMC and bypassing the NMC and the two concentrations recorded.
The efficiency shall be determined using the following equation:
EM ¼ 1 Ä
CHCðw=NMCÞ CHCðw=oNMCÞ
where:
3.2.1.1.3.3.2.
CHC(w/NMC)
is the HC concentration with CH4 flowing through the NMC, ppm C;
CHC(w/oNMC)
is the HC concentration with CH4 bypassing the NMC, ppm C.
Ethane conversion efficiency, EE The ethane/air calibration gas shall be flowed to the FID through the NMC and bypassing the NMC and the two concentrations recorded.
The efficiency shall be determined using the following equation:
EE ¼ 1 Ä
CHCðw=NMCÞ CHCðw=oNMCÞ
where: CHC(w/NMC)
is the HC concentration with C2H6 flowing through the NMC, ppm C;
CHC(w/oNMC)
is the HC concentration with C2H6 bypassing the NMC, ppm C.