CEM 2021

CEM - Abstract

Abstract Title: Determination of measurement uncertainty associated with methane concentration in sample bag using one-point close-match calibration with standard gas cylinder
Abstract Type: Oral
Session Choice: Other
Presenter Name: Prof Namgoo Kang
Company/Organisation: Korea Research Institute of Science and Technology and University of Science and Technology
Country: Korea, South

Abstract Information :

An accurate determination of the mole fraction of methane is an important task in reliable estimation of methane emission from various sources in developing national greenhouse gas emission inventory. In this study, we experimentally tested four different gas sampling methods to be able to minimize biases of the mole fractions of methane in sample bags from those in calibration gas cylinders when using a gas chromatograph with a flame ionization detector (GC-FID) based on one-point close-match (OPCM) calibration. In order to quantitatively evaluate the magnitudes of such biases we newly developed a measurement uncertainty estimation model based on the OPCM calibration. We found that the measured biases of the mole fractions of methane in the sample bags from those in the calibration cylinders can exceed significantly the expanded uncertainties associated with the mole fractions of methane in the sample bags. We also found that the mole fractions and uncertainties estimated by our model was nearly identical to those estimated by the well-known one-point through-origin (OPTO) calibration under the experimental conditions tested in this study. Information provided in this study would be useful not only to national metrology institutes for the purpose of international comparisons in gas metrology but to environmental scientists for practical field studies. This work was supported by Rural Development Administration, Republic of Korea under Cooperative Research Program for Agriculture Science & Technology Development (No. PJ014853042020).