Detection system and detection method for measuring content of heavy rare gas in natural gas

Abstract

The invention relates to a detection system for measuring content of heavy rare gas in natural gas. The system comprises a sample quantifying section, a purification section, an enriching section anda separation and detection section. A detection method comprises the following steps: after quantitatively sampling a sample in the sample quantifying section, feeding the sample into the sample purification section; adsorbing and removing active gas besides rare gas components through a zirconium aluminum furnace and a zirconium aluminum getter pump; then feeding the gas to the sample enriching section to enrich target gas components and loading the sample to the sample separation and detection section online; and separating and detecting the sample through a capillary chromatographic columnof a thick membrane molecular sieve and a TCD detector to obtain content values of the components. The system and method provided by the invention change the conventional analytic means of testing rare gas components in natural gas by means of quadrupole spectrometry, gas chromatography and sample enriching technology are combined by way of on online sample feeding mode, the system has a good vacuum state by means of an ultra-high vacuum value, influences caused by manual factors and air microleakage are avoided, the sensitivity of the analyzing method is improved favorably and the limit of detection is improved, and separation and accurate detection of heavy rare gas are achieved.

Description

technical field [0001] The invention belongs to the field of oil and gas accumulation geological exploration, and in particular relates to a detection system and a detection method for measuring the content of heavy and rare gases in natural gas. Background technique [0002] The study of rare gas components and isotopes in natural gas has broad application prospects in the geochemical study of oil and gas accumulation, mainly in the aspects of gas source tracing, migration, genetic identification, and crust-mantle interaction. The light rare gas helium and the heavy rare gas argon indicators are combined to estimate the age of natural gas source rocks and identify the structural background of oil and gas basins, and become an important geochemical index for tracing natural gas accumulation. The heavy rare gases krypton and xenon can also further indicate whether there is a contribution of mantle-derived or crust-derived volatiles in natural gas. In recent years, some schol...

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Problems solved by technology

Quadrupole mass spectrometer can measure five rare gas components of helium, neon, argon, krypton, and xenon at one time, but quadrupole mass filter has a certain discrimination effect on large mass numbers such as argon, krypton, and xenon. When the same sample When entering the quadrupole, the response signal of small mass number helium and neon will be higher, on the contrary, the response signal of large mass number is very low, this phenomenon will also exist when samples of different concentrations enter the quadrupole, and the analysis error is large, so Its test results have a large uncertainty

The volume content of methane in hydrocarbon gases is mostly about 90%, and the volume content of heavy rare gases is about 10%. -4 -10 -8 , if the noble gas components are measured directly, the detector has great limitations in the component concentration detection technology with such a wide linear range

(3) For general chromatographic separation columns, krypton and nitrogen have a relatively close peak time, and the N in natural gas components 2 Interference with the determination of trace krypton can seriously distort the results

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