NH3 line broadening coefficients and intensities measurement and impurities determination in emerging applications: CCUS, Biomethane and H2

A mid -infrared quantum cascade laser (Mid-IR QCL) coupled with a Single Pass Cell and a Multi Pass Cell, was utilized to measure ammonia (NH 3 ) absorption spectroscopic parameters and determine NH 3 impurities toward three emerging applications. We for the first time measured the pressure broadening coefficients perturbed by Air, O 2 , N 2 , He, CO 2 , CH 4 , and H 2 and the line intensities of six NH 3 transition lines near 1084.6 cm - 1 . The measured NH 3 -He, NH 3 -Air, and NH 3 -CO 2 broadening coefficients align with HITRAN database, while NH 3 -H 2 coefficients exhibit a maximum discrepancy of 46 %. Deviations between the measured line intensities and HITRAN database are minimal. Nevertheless, the uncertainties of line intensities have been significantly reduced from 20 % in HITRAN to below 3 %. The newly measured line parameters are utilized to address NH 3 impurity requirements outlined in CCUS (ISO 27913:2016), Biomethane (EN 16723:2016), and H 2 (ISO 14687:2019) standards. Based on the concept of optical gas standard (OGS), the NH 3 impurity detection requirements in all three standards have been fulfilled with an uncertainty of 1.35 %. The precision of the NH 3 -OGS is 800 part per trillion (ppt) with an integration time of 100 s. The repeatability of the NH 3 -OGS is 130 ppt for a continuous measurement time of 48 min. Notably, the NH 3 -OGS effectively addresses the highly nonlinear adsorption-desorption dynamics, underscoring the potential of OGS as a calibration -free and SI-traceable metrological gas analysis instrument.