Construction And Preliminary Test Of Chemical Composition Test System Based On Gas Chromatography Mass Spectrometry

In recent years,the automobile industry has developed rapidly and steadily.The increase of automobile production and sales and the consumption of petroleum resources aggravate the domestic environmental pollution and energy security problems.Our country has implemented more stringent emission standards,and companies are also developing and using more advanced technologies to bring higher environmental requirements to the world.The research on energy saving and emission reduction of automobile engines is still the focus of current attention,and the detection of chemical composition of substances is an important part of environmental protection.In order to facilitate the detection of unconventional pollutant emissions,research on the combustion mechanism of traditional fuels and alternative fuels,this paper chooses to build a chemical composition test system based on GC-MS.In order to meet the high requirements of the test system,such as quick and easy,the differences between different chromatographic methods are analyzed,the principle of mass spectrometry is clarified,and various parts of the test system are selected and matched.In terms of reaction system,a verification test that satisfies the combustion mechanism is designed.According to the oxidation reaction of the fuel,a Jet-Stirred Reactor is designed based on the Nancy standard.In the reactor,fuel and oxygen can be effectively mixed,and the temperature control system can be used for reaction research under different temperatures and pressures.In terms of testing system,gas chromatograph with TCD detector and single-quadrupole mass spectrometer were selected as the combined technique.Design the gas path in the system and select key components such as the column.The flow of gas and liquid into the reactor is separately controlled by a flow meter and a liquid phase pump.After the test system is built,debug the software and hardware.The external standard method is used to conduct calibration tests of standard gases using carbon dioxide and benzene as examples.In the verification test,n-pentanol was selected as the fuel under the test conditions in which the equivalent ratios were 1.0 and 0.5,the temperature was 700 K to 1100 K,and the pressure was 1 atm.The experiment found that when the selectivity is the dominant factor in chromatographic separation,a better chromatogram can be obtained byadjusting the temperature of the program.After the qualitative and quantitative analysis of the target substance to be tested is completed,the mechanism simulation results obtained by using the chemical reaction kinetic model are compared to verify the rationality of the test system construction.