ISO 6974-4-2000 天然气 用气相色谱法测定规定的不确定度的组分 第4部分:用两柱测定实验室和在线测量系统用的氮、二氧化碳和碳C1至碳C5和碳C6+的烃类

标准号：ISO 6974-4-2000
中文标准名称：天然气 用气相色谱法测定规定的不确定度的组分 第4部分:用两柱测定实验室和在线测量系统用的氮、二氧化碳和碳C1至碳C5和碳C6+的烃类
英文标准名称：Natural gas - Determination of composition with defined uncertainty by gas chromatography - Part 4: Determination of nitrogen, carbon dioxyde and C
标准类型：E24
发布日期：1999/12/31 12:00:00
实施日期：1999/12/31 12:00:00
中国标准分类号：E24
国际标准分类号：75.060
适用范围：This part of ISO 6974 describes a gas chromatographic method for the quantitative determination of natural gas constituents using a two-column system. This method is applicable to determinations made in on-line processes or in the laboratory. It is applicable to the analysis of gases containing constituents within the mole fraction ranges given in Table 1. These ranges do not represent the limits of detection, but the limits within which the stated precision of the method applies. Although one or more components in a sample may not be detected present, the method can still be applicable. This part of ISO 6974 is only applicable if used in conjunction with parts 1 and 2 of ISO 6974. NOTE 1 Oxygen is not a normal constituent of natural gas and would not be expected to be present in gas sampled for an on-line instrument. If any oxygen is present as a result of air contamination, it will be measured with the nitrogen. The resulting (nitrogen + oxygen) value will be in error to a small extent because of the slight difference between detector responses for oxygen and nitrogen. Nonetheless, the result for the natural gas/air mixture will be reasonably accurate since neither component contributes to the calorific value. NOTE 2 The content of helium and argon are assumed to be negligible and unvarying such that helium and argon need not be determined.