Non-methane hydrocarbon analysis equipment and method

Abstract

The invention relates to non-methane hydrocarbon analysis equipment and method and belongs to the technical field of organic gas detection. The non-methane hydrocarbon analysis equipment comprises a six-way valve, a quantifying ring, a first gas storage pipe, a second gas storage pipe, a multi-way valve, a molecular sieve filling pipe, a first air source and a detector. By virtue of exquisite coordination of the elements, firstly the six-way valve and the multi-way valve are arranged at load stations, so that to-be-detected gas passes through a molecular sieve, non-methane hydrocarbon in the to-be-detected gas is removed, the first gas storage pipe and the second gas storage pipe are filled with the to-be-detected gas containing no non-methane hydrocarbon, taken as background gas, and then the six-way valve and the multi-way valve are arranged at feeding stations, so that zero-level compressed air pushes air in the second gas storage pipe, the quantifying ring and the first gas storage pipe to sequentially enter the detector, namely the second gas storage pipe and the background gas in the second gas storage pipe are taken as a base line. The non-methane hydrocarbon analysis equipment and method can be used for solving the problem that errors of measured values are overlaid due to adoption of a direct minusing method when methane concentration is close to concentration of a total hydrocarbon compound, and have the advantages that detection results are accurate and the method is reliable and stable.

Description

technical field [0001] The invention relates to a gas detection method, in particular to a non-methane total hydrocarbon analysis device and method. Background technique [0002] Methane (CH 4 ) and non-methane hydrocarbons (Non-methane hydrocarbons, NMHC) are important products of nature and human activities, which are ubiquitous in the atmosphere. The background concentrations of the two in the atmosphere are about 1.8ppmv and 30ppbv respectively (R.R.Arnts .Biogenic hydrocarbon contribution to the ambient air of selected areas[J].Atmos.Enciron.,1981,15:1643-1651). Non-methane hydrocarbons, also known as non-methane total hydrocarbons (NMHC), refer to hydrocarbons other than methane. When the concentration of NMHC in the atmosphere exceeds a certain level, in addition to being directly harmful to human health, it can also produce photochemical smog under certain conditions when exposed to sunlight, which is harmful to the environment and human beings. [0003] In view o...

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Problems solved by technology

However, under continuous monitoring and isothermal conditions, whether the effect of desorption and backflushing is thorough, especially the effect of desorption and backflushing of some heavier non-methane organic substances, will directly affect the monitoring results of non-methane total hydrocarbons. Underestimate the measured value of non-methane total hydrocarbons

Moreover, during the thermal desorption process, the requirements for the thermal desorption tube are also high, which is likely to cause cross-contamination

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