A kind of vocs fixed source online monitoring and monitoring method

Abstract

The invention discloses an on-line monitoring and monitoring method for VOCs fixed sources, which includes: under normal working conditions, performing full-scan analysis on the gas discharged from VOCs fixed sources to obtain the ion intensity range of each characteristic ion; through calculation under normal working conditions The total equivalent concentration of VOCs emitted by the VOCs stationary source; the online mass spectrometer is used to conduct a full-scan analysis of the gas to be tested emitted by the VOCs stationary source in real time, and the total equivalent concentration of VOCs to be measured is obtained by calculation; the full scan of the gas to be measured The mass spectrogram and the total equivalent concentration of VOCs are compared with the full-scan mass spectrogram and the total equivalent concentration of VOCs emitted by the VOCs stationary source under normal operating conditions to determine whether the VOCs stationary source emits abnormally at this moment. The online monitoring and monitoring method of the present invention does not need to monitor a single VOC indicator and the total indicator of non-methane total hydrocarbons, effectively avoiding the restriction of the standard system of the current VOCs monitoring method.

Description

technical field [0001] The invention relates to on-line monitoring technology, in particular to an on-line monitoring and monitoring method for VOCs fixed sources. Background technique [0002] VOCs is the English abbreviation of volatile organic compounds (Volatile Organic Compounds). According to the definition of the World Health Organization (WHO), VOCs refer to a class of organic compounds with a melting point lower than room temperature and a boiling point between 50 and 260 °C, which exist in the air in the form of vapor at room temperature; while the U.S. Federal Environmental Protection Agency (EPA) It is defined as, VOCs is except CO, CO 2 、H 2 CO 3 , metal carbide, metal carbonate and ammonium carbonate, any carbon compound that participates in atmospheric photochemical reactions. Compared with atmospheric environmental protection, the definition of the US Federal Environmental Protection Agency (EPA) is more reasonable. The hazards of VOCs are mainly reflect...

AI Technical Summary

Problems solved by technology

[0007] (1) Total organic carbon (TOC) refers to the carbon concentration in the form of organic matter in the gas. It is adopted by the European Union and Japan. The measuring instruments are divided into catalytic oxidation-non-dispersive infrared detector and hydrogen ion flame ionization detector (FID). The former Limited by analytical instruments, the detection limit is high, and only high-concentration VOCs can be detected; the latter uses FID detectors, and the response values ​​to organic compounds containing heteroatoms such as oxygen, chlorine, nitrogen, and sulfur are very low and vary, so Unable to accurately characterize the total concentration of VOCs whose composition is unknown or whose composition is complex and variable and contains heteroatoms such as oxygen, chlorine, nitrogen, sulfur, etc.

[0008] (2) Total hydrocarbon (THC) is defined in my country's HJ604-2011 standard as the total amount of gaseous hydrocarbons and their derivatives measured by a hydrogen ion flame ionization detector (FID), calculated as methane; Total Methane Hydrocarbons (NMTHC) HJ / T38-1999 standard definition refers to the general term of all volatile hydrocarbons and their derivatives that respond to the FID detector except methane. As can be seen above, they are detected by FID THC and NMTHC cannot accurately characterize the total concentration of VOCs with unknown composition or complex and variable composition and containing heteroatoms such as oxygen, chlorine, nitrogen, sulfur, etc.

[0014] (1) The monitoring efficiency is low, the data output is slow, and a monitoring often takes nearly 1 hour, and a set of online monitoring device can only meet the online monitoring needs of a fixed source;

[0015] (2) Data quality is poor

When a single VOCs index is monitored online by GC-FID and GC-MS, false positives are prone to occur, resulting in inaccurate data; the total amount of non-methane total hydrocarbons cannot accurately represent the total amount of VOCs emissions containing heteroatoms such as oxygen, chlorine, and sulfur ;

[0016] (3) The online monitoring system is complicated, the operation and maintenance costs are high, daily maintenance is required, and the technical quality of personnel is required to be high;

[0017] (4) It is not suitable for online monitoring and monitoring occasions where VOCs components are unknown or complex and changeable and contain heteroatoms such as oxygen, chlorine, sulfur and other VOCs stationary sources;

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