Tanichev Aleksandr S, Petrov Dmitry V
Laboratory of Ecological Instrumentation, Institute of Monitoring of Climatic and Ecological Systems, Tomsk, Russia.
Department of Optics and Spectroscopy, Tomsk State University, Tomsk, Russia.
Appl Spectrosc. 2025 May;79(5):784-796. doi: 10.1177/00037028241282669. Epub 2024 Oct 9.
Raman spectroscopy has great potential for quantitative analysis of natural gas. Helium is one of the components of natural gas and has a wide range of applications. It was believed that noble gases could not be detected using this technique due to the absence of their vibrational spectra. In this study, we demonstrated an approach to extracting the content of helium from the Raman spectrum of methane and carried out test measurements for the first time. The approach is based on the determination of changes in the ν band of methane caused by the influence of helium and other components. The necessary spectroscopic parameters characterizing the effect of methane (CH), helium (He), nitrogen (N), carbon dioxide (CO), and ethane (CH) on the ν band of methane at a resolution of 0.35 cm were obtained. The validation of the approach showed that the helium content in natural gas can be measured with an uncertainty of 1 mol% at a sample pressure of 50 bar. The measurement precision can be increased to 0.01 mol% by using a high-resolution spectrometer. The described method does not claim to replace helium detectors, but it can be considered a valuable addition to Raman gas analysis of natural gas in developing an all-in-one device. The possibilities for further improvement of the approach are also discussed.
拉曼光谱法在天然气定量分析方面具有巨大潜力。氦气是天然气的组成成分之一，有着广泛的应用。人们曾认为由于稀有气体没有振动光谱，无法用该技术检测到它们。在本研究中，我们展示了一种从甲烷的拉曼光谱中提取氦气含量的方法，并首次进行了测试测量。该方法基于确定氦气和其他成分的影响所导致的甲烷ν带的变化。获得了在0.35 cm分辨率下表征甲烷（CH）、氦气（He）、氮气（N）、二氧化碳（CO）和乙烷（CH）对甲烷ν带影响的必要光谱参数。该方法的验证表明，在50巴的样品压力下，天然气中的氦气含量测量不确定度为1 mol%。使用高分辨率光谱仪可将测量精度提高到0.01 mol%。所描述的方法并非旨在取代氦气探测器，但在开发一体化设备时，它可被视为对天然气拉曼气体分析的一项有价值的补充。还讨论了该方法进一步改进的可能性。
