(a) If you measured an oxygenated hydrocarbon's mass concentration, first calculate its molar concentration in the exhaust sample stream from which the sample was taken (raw or diluted exhaust), and convert this into a C1-equivalent molar concentration. Add these C1-equivalent molar concentrations to the molar concentration of non-oxygenated total hydrocarbon (NOTHC). The result is the molar concentration of total hydrocarbon equivalent (THCE). Calculate THCE concentration using the following equations, noting that Eq. 1065.665-3 is required only if you need to convert your oxygenated hydrocarbon (OHC) concentration from mass to moles:[GRAPHIC] [TIFF OMITTED] TR28AP14.054 Where: xTHCE = The sum of the C1-equivalent
concentrations of non-oxygenated hydrocarbons, alcohols, and
aldehydes.xNOTHC = The sum of the C1-equivalent
concentrations of NOTHC.xOHCi = The C1-equivalent concentration of
oxygenated species i in diluted exhaust, not corrected for
initial contamination. xOHCi-init = The C1-equivalent concentration of
the initial system contamination (optional) of oxygenated
species i, dry-to-wet corrected.xTHC[THC-FID]cor = The C1-equivalent response to
NOTHC and all OHC in diluted exhaust, HC contamination and
dry-to-wet corrected, as measured by the THC-FID.RFOHCi[THC-FID] = The response factor of the FID to species i
relative to propane on a C1-equivalent basis.C = the mean number of carbon atoms in the particular compound.Mdexh = The molar mass of diluted exhaust as determined in
Sec. 1065.340.mdexhOHCi = The mass of oxygenated species i in dilute
exhaust.MOHCi = The C1-equivalent molecular weight of
oxygenated species i.mdexh = The mass of diluted exhaust.ndexhOHCi = The number of moles of oxygenated species i in
total diluted exhaust flow.ndexh = The total diluted exhaust flow.
(b) If we require you to determine nonmethane hydrocarbon equivalent (NMHCE), use the following equation: xNMHCE = xTHCE - RFCH4[THC-FID]
[middot] xCH4Eq. 1065.665-4 Where:xNMHCE = The sum of the C1-equivalent
concentrations of nonoxygenated nonmethane hydrocarbon
(NONMHC), alcohols, and aldehydes.RFCH4[THC-FID] = response factor of THC-FID to
CH4.xCH4 = concentration of CH4, HC contamination
(optional) and dry-to-wet corrected, as measured by the gas
chromatograph FID.
(c) The following example shows how to determine NMHCE emissions based on ethanol (C2H5OH), methanol (CH3OH), acetaldehyde (C2H4O), and formaldehyde (CH2O) as C1-equivalent molar concentrations: xTHC[THC-FID]cor = 145.6 [micro]mol/molxCH4 = 18.9 [micro]mol/molxC2H5OH = 100.8 [micro]mol/molxCH3OH = 1.1 [micro]mol/molxC2H4O = 19.1 [micro]mol/molxCH2O = 1.3 [micro]mol/molRFCH4[THC-FID] = 1.07RFC2H5OH[THC-FID] = 0.76RFCH3OH[THC-FID] = 0.74RFH2H4O[THC-FID] = 0.50RFCH2O[THC-FID] = 0.0xNMHCE = xTHC[THC-FID]cor - (xC2H5OH
[middot] RFC2H5OH[THC-FID] + xCH3OH
[middot] RFCH3OH[THC-FID] + xC2H4O
[middot] RFC2H4O[THC-FID] + xCH2O
[middot] RFCH2O[THC-FID]) + xC2H5OH +
xCH3OH + xC2H4O + xCH2O -
(RFCH4[THC-FID] [middot] xCH4)xNMHCE = 145.6 - (100.8 [middot] 0.76 + 1.1 [middot] 0.74 +
19.1 [middot] 0.50 + 1.3 [middot] 0) + 100.8 + 1.1 + 19.1 +
1.3 - (1.07 [middot] 18.9)xNMHCE = 160.71 [micro]mol/mol [79 FR 23805, Apr. 28, 2014]