色谱法在测定煤层气甲烷不确定度评定中的应用

Application of chromatography in the methane uncertainty evaluation of coalbed methane

煤与煤层气共采国家重点实验室利用气相色谱法对煤层气中的甲烷进行检测,根据中国合格评定委员会编制的CNAS-CL01《检测和校准实验室认可准则》,检测机构应具有及应用评定测量不确定度的程序,故需要对此方法进行不确定度的评定。从所用仪器、标气中甲烷及样品气中甲烷3个方面来确定不确定度来源,并对其进行分析,计算出合成不确定度、扩展不确定度。得出样品气中甲烷含量的测量不确定度结果为1.59%,评定过程中人员因素、环境因素等均会对结果造成影响。

Gas chromatography is used to detect methane in coalbed methane by State Key Laboratory of Coal and Coalbed Methane Co-mining. According to the CNAS-CL01 ＂Test and Calibration Laboratory Accreditation Criteria＂ compiled by the Chinese Conformity Assessment Committee, the detection institution should establish and apply the evaluation procedures of determination of the uncertainty, so it is necessary to evaluate the uncertainty of this method. The sources of the uncertainty were determined and analyzed from three aspects of the used instrument, the methane in the standard gas and in the sample gas, and the synthetic uncertainty and the extended uncertainty were calculated. It is pointed out that the uncertainty of methane content in sample gas is 1.59%, and the personnel factor and environment factor in the evaluation process will affect the result.