Online analyzer for enriching total mercury in flue gas based on dry process and analysis method

Abstract

The invention provides an online analyzer for enriching total mercury in flue gas based on a dry process and an analysis method and belongs to the technical field of environment monitoring. The online analyzer comprises an adsorbent filling system, a sample enriching system, a detection system, a filter membrane transmission system and a control acquisition system, wherein the adsorbent filling system realizes the filling of a powdered adsorbent on the surface of a filter membrane; the sample enriching system is used for enriching the total mercury in sample gas; the detection system is used for carrying out online nondestructive testing on an acquired sample; the filter membrane transmission system is used for transmitting the filter membrane among all subsystems; and the control acquisition system is used for realizing coordinated operation of all the systems and acquisition, processing and storage of all data. The analysis method comprises the following steps: filling the adsorbent, enriching the sample and detecting the sample. The online analyzer and the analysis method have the advantages that the efficient powdered adsorbent is introduced and a filter membrane enriching technology is combined, so that whole enriching of gas-state mercury and mercury particles in the flue gas or the environmental atmosphere can be realized at the same time; and an online X-ray fluorescent technology is used for detecting to finally realize the online analysis of the total mercury in the flue gas or the environmental atmosphere.

Description

technical field [0001] The invention belongs to the technical field of environmental monitoring, and in particular relates to an online analyzer and an analysis method for enriching total mercury in flue gas based on a dry method. Background technique [0002] Mercury and its compounds can enter the environment through various channels, and their emissions are mainly divided into natural sources (volcanic eruptions, etc.) and man-made sources, of which man-made sources are the main source of mercury pollution, and fuel combustion is the most important aspect of man-made activities . Studies have shown that global coal-burning mercury emissions account for about 65% of the total emissions. Based on the calculation of the average mercury content in Chinese coal of 0.188mg / kg, the factor of atmospheric mercury emissions in my country's coal-burning industry can reach as high as 70%. Among them, mercury emissions from coal-fired power plants account for more than 30% of the tota...

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Problems solved by technology

[0003] The current mainstream flue gas mercury online analyzer is mainly aimed at the determination of gaseous mercury (including elemental mercury and ionized mercury), and cannot measure particulate mercury, so the detection of total mercury cannot be realized

The determination of gaseous mercury is mainly through the enrichment method of gold amalgam. This method is expensive and requires high-purity carrier gas purge after enrichment, which is convenient for subsequent detection by cold atomic fluorescence or cold atomic absorption technology. , and both cold atomic fluorescence and cold atomic absorption techniques are directly aimed at elemental mercury (Hg 0 ) detection, in order to complete the determination of mercury in different valence states, it is often necessary to convert the mercury valence state (Hg 2+ →Hg 0 ), the generally adopted methods are thermal catalytic conversion method and high temperature conversion method, wherein, the thermal catalytic conversion method converts ionic mercury into elemental mercury through catalytic reaction under the condition of 200-400 ° C, due to the adoption of catalytic reaction, The conversion temperature is lower than the high temperature conversion temperature, the catalytic treatment is relatively simple, and no chemical reagents are required, but in order to prevent catalyst poisoning, a spare conversion system needs to be configured, which brings about an increase in the cost of the instrument, and there is also a problem with the life of the catalyst; the high temperature conversion method Ionic mercury will be reduced to elemental mercury at high temperature (>800°C). This method does not require the use of chemical reagents and catalysts. The conversion method is reliable at high temperatures, but it has high requirements for instruments and pipelines. At the same time High temperature poses safety hazards and brings about an increase in overall instrument energy consumption

In addition, the above-mentioned online analysis methods are all destructive tests and cannot save samples for subsequent laboratory data verification

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