### U.S. Code of Federal Regulations

Regulations most recently checked for updates: Sep 19, 2024

§ 1065.675 - CLD quench verification calculations.

Perform CLD quench-check calculations as follows:

(a) Perform a CLD analyzer quench verification test as described in § 1065.370.

(b) Estimate the maximum expected mole fraction of water during emission testing, xH2Oexp. Make this estimate where the humidified NO span gas was introduced in § 1065.370(e)(6). When estimating the maximum expected mole fraction of water, consider the maximum expected water content in intake air, fuel combustion products, and dilution air (if applicable). If you introduced the humidified NO span gas into the sample system upstream of a sample dryer during the verification test, you need not estimate the maximum expected mole fraction of water and you must set xH2Oexp equal to xH2Omeas.

(c) Estimate the maximum expected CO2 concentration during emission testing, xCO2exp. Make this estimate at the sample system location where the blended NO and CO2 span gases are introduced according to § 1065.370(d)(10). When estimating the maximum expected CO2 concentration, consider the maximum expected CO2 content in fuel combustion products and dilution air.

(d) Calculate quench as follows:

Where: quench = amount of CLD quench. χNOdry = concentration of NO upstream of a humidity generator, according to § 1065.370(e)(4). χNOwet = measured concentration of NO downstream of a humidity generator, according to § 1065.370(e)(9). χH2Oexp = maximum expected mole fraction of water during emission testing, according to paragraph (b) of this section. χH2Omeas = measured mole fraction of water during the quench verification, according to § 1065.370(e)(7). χNOmeas = measured concentration of NO when NO span gas is blended with CO2 span gas, according to § 1065.370(d)(10). χNOact = actual concentration of NO when NO span gas is blended with CO2 span gas, according to § 1065.370(d)(11) and calculated according to Eq. 1065.675-2. χCO2exp = maximum expected concentration of CO2 during emission testing, according to paragraph (c) of this section. χCO2act = actual concentration of CO2 when NO span gas is blended with CO2 span gas, according to § 1065.370(d)(9). Where: χNOspan = the NO span gas concentration input to the gas divider, according to § 1065.370(d)(5). χCO2span = the CO2 span gas concentration input to the gas divider, according to § 1065.370(d)(4). Example: χNOdry = 1800.0 µmol/mol χNOwet = 1739.6 µmol/mol χH2Oexp = 0.030 mol/mol χH2Omeas = 0.030 mol/mol χNOmeas = 1515.2 µmol/mol χNOspan = 3001.6 µmol/mol χCO2exp = 3.2% χCO2span = 6.1% χCO2act = 2.98% quench = (−0.0036655−0.014020171) · 100% = −1.7685671% [73 FR 59340, Oct. 8, 2008, as amended at 76 FR 57466, Sept. 15, 2011; 81 FR 74188, Oct. 25, 2016; 86 FR 34568, June 29, 2021; 88 FR 4686, Jan. 24, 2023]