(a) THC determination and initial THC/CH4 contamination corrections.
(1) If we require you to determine THC emissions, calculate xTHC[THC-FID]cor using the initial THC contamination concentration xTHC[THC-FID]init from § 1065.520 as follows:
xTHC[THC-FID]cor = xTHC[THC-FID]uncor − xTHC[THC-FID]init
Eq. 1065.660-1
Example:
χTHCuncor = 150.3 µmol/mol
χTHCinit = 1.1 µmol/mol
χTHCcor = 150.3—1.1
χTHCcor = 149.2 µmol/mol
(2) For the NMHC determination described in paragraph (b) of this section, correct χTHC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct χTHC[NMC-FID] for initial contamination of the CH4 sample train using Eq. 1065.660-1, substituting in CH4 concentrations for THC.
(3) For the NMNEHC determination described in paragraph (c) of this section, correct χTHC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct χTHC[NMC-FID] for initial contamination of the CH4 sample train using Eq. 1065.660-1, substituting in CH4 concentrations for THC.
(4) For the CH4 determination described in paragraph (d) of this section, you may correct χTHC[NMC-FID] for initial THC contamination of the CH4 sample train using Eq. 1065.660-1, substituting in CH4 concentrations for THC.
(5) You may calculate THC as the sum of NMHC and CH4 if you determine CH4 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, C2H6, and CH4 if you determine CH4 with an FTIR as described in paragraph (d)(2) of this section, C2H6 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, χNMHC:
(1) If you do not measure CH4, 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 χNMHC 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 CH4 response factor, RFCH4[THC-FID], from § 1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, χTHC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected CH4 concentration, χTHC[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:
χNMHC = concentration of NMHC.
χTHC[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.
χTHC[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.
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
RFPFC2H6[NMC-FID] = NMC combined C2H6 response factor and penetration fraction, according to § 1065.365(d).
RFPFCH4[NMC-FID] = NMC combined CH4 response factor and penetration fraction, according to § 1065.365(d).
Example:
χTHC[THC-FID]cor = 150.3 µmol/mol
χTHC[NMC-FID]cor = 20.5 µmol/mol
RFPFC2H6[NMC-FID] = 0.019
RFPFCH4[NMC-FID] = 1.000
RFCH4[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:
χNMHC = concentration of NMHC.
χTHC[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.
PFCH4[NMC-FID] = NMC CH4 penetration fraction, according to § 1065.365(e).
χTHC[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.
PFC2H6[NMC-FID] = NMC C2H6 penetration fraction, according to § 1065.365(e).
Example:
χTHC[THC-FID]cor = 150.3 µmol/mol
PFCH4[NMC-FID] = 0.990
χTHC[NMC-FID]cor = 20.5 µmol/mol
PFC2H6[NMC-FID] = 0.020
(iii) Use the following equation for an NMC configured as described in § 1065.365(f):
Eq. 1065.660-4
Where:
χNMHC = concentration of NMHC.
χTHC[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.
PFCH4[NMC-FID] = NMC CH4 penetration fraction, according to § 1065.365(f).
χTHC[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.
RFPFC2H6[NMC-FID] = NMC combined C2H6 response factor and penetration fraction, according to § 1065.365(f).
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
Example:
χTHC[THC-FID]cor = 150.3 µmol/mol
PFCH4[NMC-FID] = 0.990
χTHC[NMC-FID]cor = 20.5 µmol/mol
RFPFC2H6[NMC-FID] = 0.019
RFCH4[THC-FID] = 0.980
(3) For a GC-FID or FTIR, calculate χNMHC using the THC analyzer's CH4 response factor, RFCH4[THC-FID], from § 1065.360, and the initial THC contamination and dry-to-wet corrected THC concentration, χTHC[THC-FID]cor, as determined in paragraph (a) of this section as follows:
χNMHC = χTHC[THC-FID]cor − RFCH4[THC-FID] · χCH4
Eq. 1065.660-5
Where:
χNMHC = concentration of NMHC.
χTHC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID.
RFCH4[THC-FID] = response factor of THC-FID to CH4.
χCH4 = concentration of CH4, dry-to-wet corrected, as measured by the GC-FID or FTIR.
Example:
χTHC[THC-FID]cor = 145.6 µmol/mol
RFCH4[THC-FID] = 0.970
χCH4 = 18.9 µmol/mol
χNMHC = 145.6—0.970 · 18.9
χNMHC = 127.3 µmol/mol
(4) For an FTIR, calculate χNMHC by summing the hydrocarbon species listed in § 1065.266(c) as follows:
Eq. 1065.660-6
Where:
χNMHC = concentration of NMHC.
χHCi = the C1-equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination.
χHCi-init = the C1-equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR.
Example:
χC2H6 = 4.9 µmol/mol
χC2H4 = 0.9 µmol/mol
χC2H2 = 0.8 µmol/mol
χC3H8 = 0.4 µmol/mol
χC3H6 = 0.5 µmol/mol
χC4H10 = 0.3 µmol/mol
χCH2O = 0.8 µmol/mol
χC2H4O = 0.3 µmol/mol
χCH2O2 = 0.1 µmol/mol
χCH4O = 0.1 µmol/mol
χNMHC = 4.9 + 0.9 + 0.8 + 0.4 + 0.5 + 0.3 + 0.8 + 0.3 + 0.1 + 0.1
χNMHC = 9.1 µmol/mol
(c) NMNEHC determination. Use one of the following methods to determine NMNEHC concentration, χNMNEHC:
(1) Calculate χNMNEHC 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 C2H6, 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 χNMNEHC using the THC analyzer's CH4 response factor, RFCH4[THC-FID], and C2H6 response factor, RFC2H6[THC-FID], from § 1065.360, the initial contamination and dry-to-wet corrected THC concentration, χTHC[THC-FID]cor, as determined in paragraph (a) of this section, the dry-to-wet corrected CH4 concentration, χCH4, as determined in paragraph (d) of this section, and the dry-to-wet corrected C2H6 concentration, χC2H6, as determined in paragraph (e) of this section as follows:
χNMNEHC = χTHC[THC-FID}cor − RFCH4{THC-FID}. χCH4 − RFC2H6{THC-FID] . χC2H6
Eq. 1065.660-7
Where:
χNMNEHC = concentration of NMNEHC.
χTHC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID.
RFCH4[THC-FID] = response factor of THC-FID to CH4.
χCH4 = concentration of CH4, dry-to-wet corrected, as measured by the GC-FID, NMC FID, or FTIR.
RFC2H6[THC-FID] = response factor of THC-FID to C2H6.
χC2H6 = the C1-equivalent concentration of C2H6, dry-to-wet corrected, as measured by the GC-FID or FTIR.
Example:
χTHC[THC-FID]cor = 145.6 µmol/mol
RFCH4[THC-FID] = 0.970
χCH4 = 18.9 µmol/mol
RFC2H6[THC-FID] = 1.02
χC2H6 = 10.6 µmol/mol
χNMNEHC = 145.6 − 0.970 · 18.9 − 1.02 · 10.6
χNMNEHC = 116.5 µmol/mol
(3) For an FTIR, calculate xNMNEHC by summing the hydrocarbon species listed in § 1065.266(c) as follows:
Eq. 1065.660-8
Where:
χNMNEHC = concentration of NMNEHC.
χHCi = the C1-equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination.
χHCi-init = the C1-equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR.
Example:
χC2H4 = 0.9 µmol/mol
χC2H2 = 0.8 µmol/mol
χC3H8 = 0.4 µmol/mol
χC3H6 = 0.5 µmol/mol
χC4H10 = 0.3 µmol/mol
χCH2O = 0.8 µmol/mol
χC2H4O = 0.3 µmol/mol
χCH2O2 = 0.1 µmol/mol
χCH4O = 0.1 µmol/mol
χNMNEHC = 0.9 + 0.8 + 0.4 + 0.5 + 0.3 + 0.8 + 0.3 + 0.1 + 0.1
xNMNEHC = 4.2 µmol/mol
(d) CH4 determination. Use one of the following methods to determine methane (CH4) concentration, χCH4:
(1) For an NMC, calculate xCH4 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 CH4 response factor, RFCH4[THC-FID], from § 1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, χTHC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected CH4 concentration, χTHC[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:
χCH4 = concentration of CH4.
χTHC[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.
χTHC[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.
RFPFC2H6[NMC-FID] = NMC combined C2H6 response factor and penetration fraction, according to § 1065.365(d).
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
RFPFCH4[NMC-FID] = NMC combined CH4 response factor and penetration fraction, according to § 1065.365(d).
Example:
χTHC[NMC-FID]cor = 10.4 µmol/mol
χTHC[THC-FID]cor = 150.3 µmol/mol
RFPFC2H6[NMC-FID] = 0.019
RFPFCH4[NMC-FID] = 1.000
RFCH4[THC-FID] = 1.05
(ii) Use the following equation for an NMC configured as described in § 1065.365(e):
Eq. 1065.660-10
Where:
xCH4 = concentration of CH4.
χTHC[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.
χTHC[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.
PFC2H6[NMC-FID] = NMC C2H6 penetration fraction, according to § 1065.365(e).
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
PFCH4[NMC-FID] = NMC CH4 penetration fraction, according to § 1065.365(e).
Example:
χTHC[NMC-FID]cor = 10.4 µmol/mol
χTHC[THC-FID]cor = 150.3 µmol/mol
PFC2H6[NMC-FID] = 0.020
RFCH4[THC-FID] = 1.05
PFCH4[NMC-FID] = 0.990
(iii) Use the following equation for an NMC configured as described in § 1065.365(f):
Eq. 1065.660-11
Where:
χCH4 = concentration of CH4.
χTHC[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.
χTHC[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.
RFPFC2H6[NMC-FID] = the combined C2H6 response factor and penetration fraction of the NMC, according to § 1065.365(f).
PFCH4[NMC-FID] = NMC CH4 penetration fraction, according to § 1065.365(f).
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
Example:
χTHC[NMC-FID]cor = 10.4 µmol/mol
χTHC[THC-FID]cor = 150.3 µmol/mol
RFPFC2H6[NMC-FID] = 0.019
PFCH4[NMC-FID] = 0.990
RFCH4[THC-FID] = 1.05
(2) For a GC-FID or FTIR, xCH4 is the actual dry-to-wet corrected CH4 concentration as measured by the analyzer.
(e) C2 H6 determination. For a GC-FID or FTIR, χC2H6 is the C1-equivalent, dry-to-wet corrected C2H6 concentration as measured by the analyzer.
[89 FR 29819, Apr. 22, 2024]