天然气发热量间接测量不确定度评估方法初探

摘要

天然气发热量作为天然气的主要使用性能指标，按现代分析计量学要求，发热量值的分析测试需要给出其不确定度。相比使用仪器直接测量天然气发热量值，使用天然气组成计算天然气发热量的间接测量法，也需要进行不确定度评估。使用不确定度传递原则，初步探讨了使用天然气组成及其不确定度进行发热量不确定度评估的方法。并以称量法制备的两元气体标准物质为例，使用气体标准物质的组成不确定度进行发热量不确定度评估，标准物质发热量不确定度为0.1%级别。%Calorific value is one of the most important indexes of natural gas.Modern metrology requires all the testing results including calorific value exhibited with uncertainty.Comparing direct measurement of calorific value by heat-determiner,the indirect measurement of natural gas calorific value by calculation from the composition of natural gas requires the uncertainty estimation.In the ar-ticle,the uncertainty estimation of calorific value from the uncertainty of composition is discussed.U-sing reference gas prepared by gravimetric method with two components as an example,the uncertain-ty of the calorific value is about 0.1%.