Device and method for directly detecting non-methane hydrocarbon content

Abstract

The invention discloses a device for directly detecting non-methane hydrocarbon content. The device comprises a sample gas channel, two gas carrying channels, a sample loop, a chromatographic column,a multi-pass sample inlet valve, two gas storage pipes and a detector. In a load state, after sample gas is successively filled in the two gas storage pipes, non-methane hydrocarbon in the sample gasis eliminated through the chromatographic column for filling the sample loop, thereby finishing a quantitative sampling process. In this state, first carrying gas successively enters a first gas storage pipe, the sample loop and a second gas storage pipe and then enters the detector, thereby obtaining a non-methane hydrocarbon chromatographic peak with background gas as a baseline, and finishing direct detection for the non-methane hydrocarbon content. Second carrying gas performs backflush cleaning on the chromatographic column. The device and the method can realize direct detection for the non-methane hydrocarbon content in a one-time sample entering condition, and settles a problem of detected value error superposing caused by a subtraction method when the background concentration of the non-methane hydrocarbon in the sample is far lower than the methane concentration. Furthermore the device and the method have advantages of high detection result accuracy, reliable and stable method, etc.

Description

technical field [0001] The invention belongs to the technical field of technical gas detection, in particular to a device and method for direct detection of non-methane total hydrocarbon content. Background technique [0002] The concentration of methane and non-methane total hydrocarbons in the atmosphere is about 1.8ppmv and 30ppbv. Non-methane total hydrocarbons refer to all volatile hydrocarbons (mainly C2-C8) except methane. When the non-methane total hydrocarbons in the atmosphere exceed a certain concentration, in addition to being directly harmful to human health, photochemical smog can also be produced by sunlight under certain conditions, which is harmful to the environment and human beings. Therefore, it is very necessary to monitor and control non-methane total hydrocarbons in areas such as ambient air and factory boundaries. Among them, the factory boundary concentration standard of non-methane total hydrocarbons in my country's "Integrated Emission Standards f...

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Problems solved by technology

[0005] The invention provides a device for direct detection of non-methane total hydrocarbon content, which realizes direct detection of non-methane total hydrocarbons under the condition of one-time sample injection, and solves the problem that when the background non-methane hydrocarbon concentration in the sample is far less than the methane concentration, The detection value error superposition problem caused by the subtraction method has the advantages of accurate detection results, reliable and stable methods, etc.

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