Online environmental detection VOC chromatograph

Online environmental detection VOC chromatograph
Environmental testing execution reference standard:
HJ/T604-2011 Determination of Total Hydrocarbons in Environmental Air Gas Chromatography Method
HJ/T38-1999 Determination of Non Methane Total Hydrocarbons in National Pollution Source Emissions Gas Chromatography Method
GB 16297-1996 Comprehensive Emission Standard for Air Pollutants
WS/T141-1999 Determination of Non Methane Total Hydrocarbons in Workplace Air by Gas Chromatography
GB/T 16157-1996 Determination of particulate matter and sampling methods for gaseous pollutants in exhaust gas from fixed pollution sources
Monitoring and Analysis Methods for Air and Waste Gas, Fourth Edition (pg.585) - Total Hydrocarbons and Non Methane Total Hydrocarbons
Non methane total hydrocarbon VOC analysis:
Non methane hydrocarbons (NMHC) typically refer to all volatile hydrocarbons (mainly C2 to C8) other than methane, also known as non methane total hydrocarbons. When the concentration of NMHC in the atmosphere exceeds a certain level, it is not only directly harmful to human health, but can also produce photochemical smog under certain conditions when exposed to sunlight, posing a threat to the environment and humans. There are many methods for monitoring NMHC in ambient air and industrial waste gas, but currently most countries use gas chromatography. Due to the high cost of instruments used for direct determination of NMHC, we adopted a dual column dual hydrogen flame ionization detector gas chromatography method to measure the content of total hydrocarbons and methane separately, with the difference between the two being the content of NMHC. The NMHC measured under specified conditions is the total amount of hydrocarbons other than methane that shows a significant response to the gas chromatography hydrogen flame ionization detector, measured in carbon.
The difference between non methane total hydrocarbons (NMHC) and volatile organic compounds (VOCs). The World Health Organization (WHO, 1989) defines total volatile organic compounds (TVOC) as the collective term for volatile organic compounds with a melting point below room temperature and a boiling point between 50-260 ℃. The definition of VOC content in the national standard "Harmful Substances in Interior Decoration Materials and Interior Wall Coatings" is: "The total volatile matter content in the coating minus the moisture content is the volatile organic compound content in the coating." The definition of VOC is divided into two categories. The first category is the general definition of VOC, which only explains what volatile organic compounds are or under what conditions they are volatile organic compounds; The other type is defined in terms of environmental protection, which means that it is the lively type of volatile organic compounds, that is, the type of volatile organic compounds that can cause harm. The World Health Organization defines Non Methane Total Hydrocarbons (NMHC) as a general term for hydrocarbons other than methane, primarily (C2 to C8).
Working principle of non methane total hydrocarbon analyzer:
The company adopts dual column, single valve, and blowback technology to achieve one-time injection analysis of methane and non methane total hydrocarbon content. The external standard calculation method is used, and the results are accurate and reliable. The sample is sucked into the quantitative ring by the pump, and the switching valve allows the sample to enter the chromatographic column with the carrier gas. Methane and non methane hydrocarbons are separated. When methane flows out of the chromatographic column and enters the detector for detection, the switching valve allows the carrier gas to blow back into the chromatographic column, causing the hydrocarbon compounds (non methane total hydrocarbons) in the column to form a peak and blow back to the detector for detection. This instrument can achieve online multi-point monitoring according to user needs.