On-line automatic sampling system and method for gas chromatographic analysis of natural gas hydrate decomposition gas

Abstract

The invention discloses a gas chromatography online automatic sampling system and method for decomposed gas of natural gas hydrate. The system comprises a first multi-path valve and a second multi-path valve, wherein a gas inlet is connected with the first multi-path valve through a first gas conveying pump, and a gas outlet is directly connected with the first multi-path valve; three input gas paths and an output gas path are connected between the first multi-path valve and the second multi-path valve, cold traps and purifying pipes are connected in the input gas paths, and a second gas conveying pump is connected in the output gas path; two ends of a sample loading ring are connected to the second multi-path valve; a gas chromatograph and a gas loading air source are connected with the second multi-path valve; and the gas chromatograph is controlled to start by a gas chromatography starting trigger. According to the system, to-be-tested gas can be continuously and online conveyed, the collection, drying, purification and injection of samples and the starting of gas chromatography are automatically implemented, so that the system has the advantages that the remote sampling, residual sample returning, full-closed operation, full-automatic control and the likes are realized and is suitable for being popularized.

Description

technical field [0001] The invention relates to an automatic sampling system and an automatic sampling method for on-line gas chromatographic analysis of natural gas hydrate decomposition gas, belonging to the gas sampling technology for on-line analysis of gas in the fields of petroleum exploration, mining, gathering and transportation, processing and the like. Background technique [0002] Natural gas hydrate, commonly known as combustible ice, is mainly composed of methane and is the largest oil and gas resource on earth. Realizing the industrial exploitation of natural gas hydrate and making it serve human beings is the current global technical goal. In fact, not all the gases in natural gas hydrates are methane, and there are also non-hydrocarbon gases such as nitrogen, carbon dioxide, and hydrogen sulfide, and other light hydrocarbon gases such as ethane, propane, and butane. Therefore, the composition of natural gas hydrate decomposition gas is a key parameter to eva...

AI Technical Summary

Problems solved by technology

However, these equipments are immature for the current mining technology, the gas production rate is unstable during the mining process, and the moisture content of the output gas is high, and the output of natural gas hydrate mining sites rich in nitrogen, carbon dioxide, hydrogen sulfide and other non-hydrocarbon gases In terms of gas online monitoring, there are still serious technical problems such as the narrow range of gas source pressure adaptation, lack of analysis capabilities for non-hydrocarbon gas components, and the inability to overcome the interference of water vapor and hydrogen sulfide on chromatographic analysis and the poisoning of chromatographic columns. There are disadvantages such as no remote sample collection capability, residual air collected cannot be returned, and high safety and health risks

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