A volatile organic compound double cold trap sampling unit, sampling system and method

Abstract

The invention relates to a volatile organic compound double cold trap sampling unit, a sampling system and a method. In the sampling unit, a two-way valve V1 is arranged between the sample inlet and the first four-way valve, and a two-way valve V2 is arranged between the sample inlet and the second four-way valve; The valve V1, the high-carbon enrichment cold trap communicates with the first detector, and the second four-way valve communicates with the two-way valve V2, the low-carbon enrichment cold trap and the second detector respectively; the high-carbon enrichment cold trap communicates with the first A two-way valve V3 is set between the four-way, a two-way valve V4 is set between the low-carbon enrichment cold trap and the second four-way; a two-way valve V5 is set between the first four-way and the exhaust port, and the second There is a two-way valve V6 between the four-way and the exhaust port; the first four-way, the first carrier gas inlet and the first detector are connected through the three-way valve V7, and the second four-way, the second carrier gas inlet and the second The detector communicates through the three-way valve V8. The invention can realize the enrichment and detection of low-concentration pollutants, and the sampling system can realize full-time and no-time blind spot detection.

Description

technical field [0001] The invention relates to the field of environmental science, in particular to a volatile organic compound double-cold-trap sampling unit and enrichment sampling method, as well as a sampling system and method containing a plurality of volatile organic compound double-cold-trap sampling units. Background technique [0002] Volatile organic compounds (VOCs) are ubiquitous in the atmosphere and have the most serious impact on the environment. VOCs mainly come from motor vehicle emissions (43.7%), technological processes (26.0%), fixed combustion sources (19.3%), solvent paint use (6.3%), and oil storage and transportation processes (4.7%), among which motor vehicles Exhaust emissions are the most serious. It mainly includes alkanes, aromatics, olefins, halocarbons, esters, aldehydes, ketones and other organic compounds. The composition of VOCs is complex, and most of them are photochemically reactive. Under sunlight, they interact with NO in the atmosph...

AI Technical Summary

Problems solved by technology

[0004] The main problems existing in the detection methods of volatile organic pollutants in the atmosphere in the prior art are: the continuous and uninterrupted sampling of pollutant samples cannot be realized, there are sampling blind spots, and the detection results cannot reflect the overall concentration of pollutant samples value, the measurement results are inaccurate; the high-carbon components and low-carbon components in the pollutant samples cannot be effectively separated, and the enrichment efficiency is low

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