刍议天然气能量计量的准确度与不确定度

Discussions on the Accuracy and Uncertainty in Measuring Natural Gas Energy

推荐性国家标准"天然气能量的测定"报批稿第11章11.1节中所谓的准确度实质上是指在特定界面上实施能量计量时计量系统应达到的(准确度)等级;而11.2节中所谓的不确定度计算是指相对不确定度的计算。因此,相对不确定度u(E)实际上是指(整个)计量系统的准确度等级;而相对不确定度uH及uQ则分别指发热量测定和气体流量测定这两个功能模块的最大允许误差(MPE)。对气相色谱法(间接)测定发热量的测量不确定度评定问题提出看法;并对开发天然气能量计量技术提出了若干建议。

The accuracy in the first part of Chapter 11 of recommended national standards ＂Determination of Natural Gas Energy＂ actually refers to the accuracy that measuring system should reach in carrying out the measurement on the special interface, while the uncertainty calculation in the second part of Chapter 11 means the calculation of relative uncertainty. In other words, the relative un- certainty u（E）, in fact, is the rank of uncertainty in the whole measuring system, but the relative uncertainty uH and uQ relatively re- fer to the maximum permissible errors （MPE） of two functional blocks： the determination of calorifie value and gas flow rate. Therefore, some opinions are offered to the assessment of measuring uncertainty when gas chromatography is used to determine the calorific val- ue, followed by some suggestions about the development of measuring technology of natural gas energy.