氢燃料品质分析中基于临界流锐孔的气体稀释方法

Gas dilution method based on critical flow orifices in gas analysis for hydrogen fuel quality

关键词:  氢燃料  气体稀释方法  微痕量  临界流锐孔  响应因子 

Key words:  hydrogen fuel  gas dilution method  micro-trace  critical flow orifices  response factor

摘要:

目的 解决国内氢能产业高质量发展中的氢燃料微痕量杂质组分准确分析难题。方法 建立了基于临界流锐孔原理的气体稀释方法以适用于氢燃料品质分析,由于氢燃料品质分析中待测样品主组分为氢气而不是氮气,故引入响应因子数学模型,研究了对不同种类气体的流量影响。结果 经实验验证,气体稀释方法的稀释比达到1∶1 000以上,稀释比相对扩展不确定度优于1%,实现了动态发生微痕量级(摩尔分数10-9)水平的氢中甲醛、甲烷组分的气体标准物质,其含量测量结果的重复性不大于7%,各稀释含量间线性相关系数R²大于0.999。结论 氮中甲醛和氢中甲醛的分析实验结果验证了响应因子数学模型的可靠性,并且经过响应因子修正后的气体稀释方法可明显提高分析结果的准确性。 

Abstract:

Objective The aim is to solve the analysis problems on the accurate determination of micro-trace impurity components in the high-quality development of China's hydrogen energy industry. Methods For the quality analysis of hydrogen fuel, a gas dilution method based on the principle of critical flow orifices was established. As the major component of the sample to be tested is hydrogen rather than nitrogen, the math module of flow response factor is studied to investigate the influences on the flow of different gases. Results The dilution ratio of this method could achieve over 1∶1 000 with a relative expand uncertainty of better than 1%. The gas reference materials, namely formaldehyde and methane in hydrogen, are prepared in a 10-9 molar fraction level dynamically. The measured repeatability of concentrations of the gas reference materials is no more than 7%. The linear correlation coefficient R² of each diluted concentration is more than 0.999. Conclusion sThe analysis results of formaldehyde in nitrogen and in hydrogen respectively conclude that the math module of flow response factor is reliable, and the accuracy of this gas dilution method will be improved after a correction by flow response factor.