Semi-volatile organic matter sampling technique in exhaust emission pipe

Abstract

The invention relates to a technical method for taking samples of semi-volatile organic compounds SVOC in a waste gas discharge pipe. The isokinetic sampling principle is adopted. A filter cylinder, a liquid collection bottle and an absorbent are used for collecting SVOC samples from the waste gas discharge pipe. The structure mainly consists of a sampling device and an isokinetic sampler mainframe; the sampling device comprises a pitot tube, a temperature sensor, a humidity sensor, the filter cylinder, a heating insulating device, a condensation device, the liquid collection bottle, an absorption tank, and an absorbent. When in sampling, the sampling device is inserted into the waste gas discharge pipe; a microprocessor in the isokinetic sampler tracks the discharge flow velocity of the sampling point; the purpose of isokinetic sampling can be achieved by maintaining the isokinetic sampling conditions; the SVOC samples in the form of particle in the waste gas discharge pipe are collected in the filter cylinder; the SVOC samples in the form of steam flow into the liquid collection bottle after being condensed; the SVOC samples in gas phase state are collected by the absorbent in the absorption tank; the rest gas after passing through the isokinetic sampler is discharged by an air extracting pump into the atmosphere; and after the sampling ends, samples collected in the filter cylinder, the liquid collection tank and the absorbent in the absorption tank are sent to a chemical laboratory for analysis.

Description

technical field [0001] The invention relates to a method for sampling semi-volatile organic compounds in exhaust gas discharge pipes. Background technique [0002] Semi-volatile organic compounds (hereinafter referred to as SVOC) are contained in the exhaust gas discharged from flue, industrial waste gas discharge pipe, waste incinerator waste gas discharge pipe, etc. (hereinafter referred to as waste gas discharge pipe). These include polycyclic aromatic hydrocarbons (PAHs) organochlorine pesticides, organophosphorus pesticides, polychlorinated biphenyls, polychlorinated dibenzofurans, phthalic acid lipids, etc., which mainly exist in the form of gas, vapor, and particles. Among them, the 2-3 ring PAHs mainly exist in the gas phase, the 5-6 ring PAHs mainly exist in the particles (adsorbed on the surface of the particles), and the PAHs in between are distributed in both the gas phase and the solid phase. Mixture of gas phase and particulate matter. At present, the current...

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Problems solved by technology

However, due to the wide variety of SVOCs and their large distribution in the exhaust gas, studies have shown that the PAHs samples collected on the filter cartridge with a soot sampler are only 10% to 30% of the PAHs in the exhaust gas emissions, and the PAHs below the 4th ring are more than 10%. The gaseous form passes through the filter cartridge and cannot be collected by the filter cartridge. SVOC with a molecular weight greater than 252 can be collected on the filter cartridge. When the molecular weight is less than or equal to 252 or 3 rings, it only exists in a gaseous state and basically cannot be collected by the filter cartridge.

And when sampling, a small part of the SVOC sample adsorbed on the filter cartridge is also lost from the filter cartridge due to decomposition, adsorption and volatilization during the sampling process.

However, the gas phase SVOC in the exhaust gas has a small molecular weight and cannot be collected only by the filter cartridge. Therefore, only collecting and analyzing the SVOC samples in the particulate matter on the filter cartridge cannot truly reflect and understand the actual pollution emission of SVOC in the exhaust gas. quantity and condition

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