THC, NMHC, NMNEHC, CH 4 , and C 2 H 6 determination.

(a) THC determination and initial THC/CH 4 contamination corrections. (1) If we require you to determine THC emissions, calculate x THC[THC-FID]cor using the initial THC contamination concentration x THC[THC-FID]init from § 1065.520 as follows: x THC[THC-FID]cor = x THC[THC-FID]uncor − x THC[THC-FID]init Eq. 1065.660-1 Example: x THCuncor = 150.3 µmol/mol x THCinit = 1.1 µmol/mol x THCcor = 150.3—1.1 x THCcor = 149.2 µmol/mol (2) For the NMHC determination described in paragraph (b) of this section, correct x THC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct x THC[NMC-FID] for initial contamination of the CH 4 sample train using Eq. 1065.660-1, substituting in CH 4 concentrations for THC. (3) For the NMNEHC determination described in paragraph (c) of this section, correct x THC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct x THC[NMC-FID] for initial contamination of the CH 4 sample train using Eq. 1065.660-1, substituting in CH 4 concentrations for THC. (4) For the CH 4 determination described in paragraph (d) of this section, you may correct x THC[NMC-FID] for initial THC contamination of the CH 4 sample train using Eq. 1065.660-1, substituting in CH 4 concentrations for THC. (5) You may calculate THC as the sum of NMHC and CH 4 if you determine CH 4 with an FTIR as described in paragraph (d)(2) of this section and NMHC with an FTIR using the additive method from paragraph (b)(4) of this section. (6) You may calculate THC as the sum of NMNEHC, C 2 H 6 , and CH 4 if you determine CH 4 with an FTIR as described in paragraph (d)(2) of this section, C 2 H 6 with an FTIR as described in paragraph (e) of this section, and NMNEHC with an FTIR using the additive method from paragraph (c)(3) of this section. (b) NMHC determination. Use one of the following to determine NMHC concentration, x NMHC : (1) If you do not measure CH 4 , you may omit the calculation of NMHC concentrations and calculate the mass of NMHC as described in § 1065.650(c)(5). (2) For an NMC, calculate x NMHC using the NMC's penetration fractions, response factors, and/or combined penetration fractions and response factors as described in § 1065.365, the THC FID's CH 4 response factor, RF CH4[THC-FID], from § 1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, x THC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected CH 4 concentration, x THC[NMC-FID]cor, optionally corrected for initial THC contamination as determined in paragraph (a) of this section. (i) Use the following equation for an NMC configured as described in § 1065.365(d): Eq. 1065.660-2 Where: x NMHC = concentration of NMHC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC. RF CH4[THC-FID] = response factor of THC FID to CH 4, according to § 1065.360(d). RFPF C2H6[NMC-FID] = NMC combined C 2 H 6 response factor and penetration fraction, according to § 1065.365(d). RFPF CH4[NMC-FID] = NMC combined CH 4 response factor and penetration fraction, according to § 1065.365(d). Example: x THC[THC-FID]cor = 150.3 µmol/mol x THC[NMC-FID]cor = 20.5 µmol/mol RFPF C2H6[NMC-FID] = 0.019 RFPF CH4[NMC-FID] = 1.000 RF CH4[THC-FID] = 1.05 (ii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in § 1065.365(e): Eq. 1065.660-3 Where: x NMHC = concentration of NMHC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. PF CH4[NMC-FID] = NMC CH 4 penetration fraction, according to § 1065.365(e). x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the THC FID during sampling through the NMC. PF C2H6[NMC-FID] = NMC C 2 H 6 penetration fraction, according to § 1065.365(e). Example: x THC[THC-FID]cor = 150.3 µmol/mol PF CH4[NMC-FID] = 0.990 x THC[NMC-FID]cor = 20.5 µmol/mol PF C2H6[NMC-FID] = 0.020 (iii) Use the following equation for an NMC configured as described in § 1065.365(f): Eq. 1065.660-4 Where: x NMHC = concentration of NMHC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. PF CH4[NMC-FID] = NMC CH 4 penetration fraction, according to § 1065.365(f). x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the THC FID during sampling through the NMC. RFPF C2H6[NMC-FID] = NMC combined C 2 H 6 response factor and penetration fraction, according to § 1065.365(f). RF CH4[THC-FID] = response factor of THC FID to CH 4, according to § 1065.360(d). Example: x THC[THC-FID]cor = 150.3 µmol/mol PF CH4[NMC-FID] = 0.990 x THC[NMC-FID]cor = 20.5 µmol/mol RFPF C2H6[NMC-FID] = 0.019 RF CH4[THC-FID] = 0.980 (3) For a GC-FID or FTIR, calculate x NMHC using the THC analyzer's CH 4 response factor, RF CH4[THC-FID], from § 1065.360, and the initial THC contamination and dry-to-wet corrected THC concentration, x THC[THC-FID]cor, as determined in paragraph (a) of this section as follows: χ NMHC = χ THC[THC-FID]cor − RF CH4[THC-FID] · χ CH4 Eq. 1065.660-5 Where: x NMHC = concentration of NMHC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID. RF CH4[THC-FID] = response factor of THC-FID to CH 4. x CH4 = concentration of CH 4, dry-to-wet corrected, as measured by the GC-FID or FTIR. Example: x THC[THC-FID]cor = 145.6 µmol/mol RF CH4[THC-FID] = 0.970 x CH4 = 18.9 µmol/mol x NMHC = 145.6—0.970 · 18.9 x NMHC = 127.3 µmol/mol (4) For an FTIR, calculate x NMHC by summing the hydrocarbon species listed in § 1065.266(c) as follows: Eq. 1065.660-6 Where: x NMHC = concentration of NMHC. x HCi = the C 1 -equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination. x HCi-init = the C 1 -equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR. Example: x C2H6 = 4.9 µmol/mol x C2H4 = 0.9 µmol/mol x C2H2 = 0.8 µmol/mol x C3H8 = 0.4 µmol/mol x C3H6 = 0.5 µmol/mol x C4H10 = 0.3 µmol/mol x CH2O = 0.8 µmol/mol x C2H4O = 0.3 µmol/mol x CH2O2 = 0.1 µmol/mol x CH4O = 0.1 µmol/mol x NMHC = 4.9 + 0.9 + 0.8 + 0.4 + 0.5 + 0.3 + 0.8 + 0.3 + 0.1 + 0.1 x NMHC = 9.1 µmol/mol (c) NMNEHC determination. Use one of the following methods to determine NMNEHC concentration, x NMNEHC : (1) Calculate x NMNEHC based on the test fuel's ethane content as follows: (i) If the content of your test fuel contains less than 0.010 mol/mol of ethane, you may omit the calculation of NMNEHC concentration and calculate the mass of NMNEHC as described in § 1065.650(c)(6)(i). (ii) If the content of your fuel test contains at least 0.010 mol/mol of C 2 H 6 , you may omit the calculation of NMNEHC concentration and calculate the mass of NMNEHC as described in § 1065.650(c)(6)(ii). (2) For a GC-FID, NMC FID, or FTIR, calculate x NMNEHC using the THC analyzer's CH 4 response factor, RF CH4[THC-FID], and C 2 H 6 response factor, RF C2H6[THC-FID], from § 1065.360, the initial contamination and dry-to-wet corrected THC concentration, x THC[THC-FID]cor, as determined in paragraph (a) of this section, the dry-to-wet corrected CH 4 concentration, x CH4, as determined in paragraph (d) of this section, and the dry-to-wet corrected C 2 H 6 concentration, x C2H6, as determined in paragraph (e) of this section as follows: x NMNEHC = x THC[THC-FID}cor − RF CH4{THC-FID} . x CH4 − RF C2H6{THC-FID] . x C2H6 Eq. 1065.660-7 Where: x NMNEHC = concentration of NMNEHC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID. RF CH4[THC-FID] = response factor of THC-FID to CH 4. x CH4 = concentration of CH 4, dry-to-wet corrected, as measured by the GC-FID, NMC FID, or FTIR. RF C2H6[THC-FID] = response factor of THC-FID to C 2 H 6. x C2H6 = the C 1 -equivalent concentration of C 2 H 6, dry-to-wet corrected, as measured by the GC-FID or FTIR. Example: x THC[THC-FID]cor = 145.6 µmol/mol RF CH4[THC-FID] = 0.970 x CH4 = 18.9 µmol/mol RF C2H6[THC-FID] = 1.02 x C2H6 = 10.6 µmol/mol x NMNEHC = 145.6 − 0.970 · 18.9 − 1.02 · 10.6 x NMNEHC = 116.5 µmol/mol (3) For an FTIR, calculate x NMNEHC by summing the hydrocarbon species listed in § 1065.266(c) as follows: Eq. 1065.660-8 Where: x NMNEHC = concentration of NMNEHC. x HC i = the C 1 -equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination. x HC i -init = the C 1 -equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR. Example: x C2H4 = 0.9 µmol/mol x C2H2 = 0.8 µmol/mol x C3H8 = 0.4 µmol/mol x C3H6 = 0.5 µmol/mol x C4H10 = 0.3 µmol/mol x CH2O = 0.8 µmol/mol x C2H4O = 0.3 µmol/mol x CH2O2 = 0.1 µmol/mol x CH4O = 0.1 µmol/mol x NMNEHC = 0.9 + 0.8 + 0.4 + 0.5 + 0.3 + 0.8 + 0.3 + 0.1 + 0.1 x NMNEHC = 4.2 µmol/mol (d) CH 4 determination. Use one of the following methods to determine methane (CH 4 ) concentration, x CH4 : (1) For an NMC, calculate x CH4 using the NMC's penetration fractions, response factors, and/or combined penetration fractions and response factors as described in § 1065.365, the THC FID's CH 4 response factor, RF CH4[THC-FID], from § 1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, x THC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected CH 4 concentration, x THC[NMC-FID]cor, optionally corrected for initial THC contamination as determined in paragraph (a) of this section. (i) Use the following equation for an NMC configured as described in § 1065.365(d): Eq. 1065.660-9 Where: x CH4 = concentration of CH 4 . x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. RFPF C2H6[NMC-FID] = NMC combined C 2 H 6 response factor and penetration fraction, according to § 1065.365(d). RF CH4[THC-FID] = response factor of THC FID to CH 4, according to § 1065.360(d). RFPF CH4[NMC-FID] = NMC combined CH 4 response factor and penetration fraction, according to § 1065.365(d). Example: x THC[NMC-FID]cor = 10.4 µmol/mol x THC[THC-FID]cor = 150.3 µmol/mol RFPF C2H6[NMC-FID] = 0.019 RFPF CH4[NMC-FID] = 1.000 RF CH4[THC-FID] = 1.05 (ii) Use the following equation for an NMC configured as described in § 1065.365(e): Eq. 1065.660-10 Where: x CH4 = concentration of CH 4. x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. PF C2H6[NMC-FID] = NMC C 2 H 6 penetration fraction, according to § 1065.365(e). RF CH4[THC-FID] = response factor of THC FID to CH 4, according to § 1065.360(d). PF CH4[NMC-FID] = NMC CH 4 penetration fraction, according to § 1065.365(e). Example: x THC[NMC-FID]cor = 10.4 µmol/mol x THC[THC-FID]cor = 150.3 µmol/mol PF C2H6[NMC-FID] = 0.020 RF CH4[THC-FID] = 1.05 PF CH4[NMC-FID] = 0.990 (iii) Use the following equation for an NMC configured as described in § 1065.365(f): Eq. 1065.660-11 Where: x CH4 = concentration of CH 4. x THC[NMC-FID]cor = concentration of THC, initial THC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC. x THC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC. RFPF C2H6[NMC-FID] = the combined C 2 H 6 response factor and penetration fraction of the NMC, according to § 1065.365(f). PF CH4[NMC-FID] = NMC CH 4 penetration fraction, according to § 1065.365(f). RF CH4[THC-FID] = response factor of THC FID to CH 4, according to § 1065.360(d). Example: x THC[NMC-FID]cor = 10.4 µmol/mol x THC[THC-FID]cor = 150.3 µmol/mol RFPF C2H6[NMC-FID] = 0.019 PF CH4[NMC-FID] = 0.990 RF CH4[THC-FID] = 1.05 (2) For a GC-FID or FTIR, x CH4 is the actual dry-to-wet corrected CH 4 concentration as measured by the analyzer. (e) C 2 H 6 determination. For a GC-FID or FTIR, x C2H6 is the C 1 -equivalent, dry-to-wet corrected C 2 H 6 concentration as measured by the analyzer. [89 FR 29819, Apr. 22, 2024]