Online continuous flow analysis and extraction device and method for methane carbon isotope composition in gas

Abstract

The invention belongs to the technical field of determination of carbon isotope composition of methane in gas, and particularly discloses an online continuous flow extraction device for methane in gasand a carbon isotope composition analysis method. The device comprises a first six-way valve, a plurality of helium inlets communicated with the first six-way valve, a second six-way valve communicated with the first six-way valve, a helium inlet communicated with the second six-way valve, a carbon dioxide collecting pipe communicated with the second six-way valve, a single-opening quartz tube communicated with the second six-way valve, and a stable isotope mass spectrometer communicated with the second six-way valve. The method comprises the following steps of: 1, loading a gas sample; 2, conducting blow-back degassing, and completely exhausting air in pipelines at the two ends of a gas collecting pipe; 3, oxidizing, purifying and collecting methane in the gas; 4, sublimating and injecting carbon dioxide; and 5, determining methane carbon isotopes. According to the invention, the problems of excessive use amount of off-line pretreatment sample preparation gas, complicated operation process and low efficiency are solved.

Description

technical field [0001] The invention belongs to the technical field of methane carbon isotope composition determination in gas, and particularly relates to an online continuous flow extraction device for methane in gas and a carbon isotope composition analysis method. Background technique [0002] Methane is chemically active and can strongly absorb infrared light waves on the surface to increase the temperature of the surface and near-surface atmosphere. It is known as the second largest greenhouse gas after carbon dioxide. By directly or indirectly obtaining methane carbon isotope analysis data, methane can be revealed. The microenvironmental mechanisms and relative contribution rates of production, transmission and release provide important information on methane sources and sinks and changes in atmospheric concentrations. In addition, the carbon isotopic composition of methane can be used to track the gas source of natural gas hydrates and gas reservoirs in the basin, an...

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Problems solved by technology

[0006] The purpose of the present invention is to provide an online continuous flow analysis and extraction device and method for methane isotope composition in gas, which solves the problems of excessive off-line pretreatment sample preparation gas consumption, cumbersome operation process, and low efficiency, and makes up for gas chromatography-mass spectrometry. The inability to test the carbon isotope composition of low-content methane and the low accuracy of laser absorption spectroscopy analysis

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