采用配有五阀(2个十通阀和3个六通阀)、七柱(2根毛细管柱和5根填充柱)和三检测器(氢火焰离子化检测器A、热导检测器B和C)的气相色谱法测定了天然气的组分。借助阀的切换系统及设置的分析程序,一次进样便可实现天然气常规组分的测定。检测器A用于烃类气体的检测,检测器B用于永久气体的检测,检测器C用于氢气检测。根据标准样品组分的保留时间对未知样品作定性检测,用外标法进行定量测定。方法的精密度符合国家标准GB/T 13610-2003中的规定,本方法所测得的由标准气体所混合组成的标准样品中,各组分的测定值与标准值之间的相对误差均小于5%。

Gas chromatograph equipped with 5 valves (2 10-way valves and 3 6-way valves), 7 columns (2 capillary columns and 5 packed columns) and 3 detectors (FID A, TCD B and TCD C), was used for componental analysis of natural gas. By applying the switching system of the valves and the pre-set analytical program, determination of the common components of a natural gas sample could be realized by a single sample introduction. Qualitative detections were performed on the base of retention times of the components in standard samples, and quantitative analysis was performed by the external standard method. Precision of the method was tested, giving results of repeatability and reproducibility in conformity with the requirements stated in the standard GB/T 13610-2003. The relative errors between the values of components in a mixed standard of standard gases found by this method and the standard values were all found to be less than 5%.