VOC monitoring device capable of separating water vapor and method for separating water vapor in sample gas

Abstract

The invention relates to a VOC monitoring device capable of separating water vapor and a method for separating the water vapor in sample gas. The VOC monitoring device is characterized by comprising adehydration sampling device and a multi-channel valve, wherein the dehydration sampling device comprises a ten-way valve, a quantitative sampling loop and a dehydration chromatographic column; and the ten-way valve has two working modes, the quantitative sampling loop is used for quantitatively measuring out the sample gas when the ten-way valve is in the second working mode, the dehydration chromatographic column is used for communicating with the quantitative sampling loop when the ten-way valve is in the first working mode and removing the water vapor in the sample gas, and the sample gasafter the water vapor is removed is fed into an enrichment tube through the multi-channel valve. The VOC monitoring device utilizes the working column temperature of the chromatographic column to separate the water vapor in the sample gas, the separation speed is high, the water removal effect is good, and other VOC components in the sample gas can be fed into the enrichment tube for enrichment, so that the disadvantages in the prior art are effectively overcome.

Description

technical field [0001] The invention relates to the technical field of VOC monitoring, in particular to a VOC monitoring device capable of separating water vapor and a method for separating water vapor in a sample gas. Background technique [0002] VOC is the English abbreviation of volatile organic compounds (volatile organic compounds); VOC in the general sense refers to volatile organic compounds; but VOC in the sense of environmental protection refers to a lively type of volatile organic compounds, that is, the one that will cause harm volatile organic compounds. [0003] The composition of air pollution factors around industrial parks is becoming more and more complex and diverse. Environmental protection departments need more online VOC monitoring equipment to continuously monitor the composition and concentration of pollution factors in ambient air; because the concentration of VOC components in ambient air is very low, usually low It is lower than 1ppbV, which makes...

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Problems solved by technology

[0005] In the actual monitoring process, because the content of water vapor in the air often reaches 3%, that is, 30000000ppbV, which is about 30 million times of the VOC component, on the one hand, the enrichment material in the enrichment tube is usually due to excessive Water vapor will cause saturation, so that VOC pollutants in the air cannot be captured; on the other hand, since the enrichment tube works below 0 degrees, it will directly cause the water vapor in the air to freeze and block the enrichment tube, resulting in enrichment The tube or even the entire VOC monitoring equipment cannot work normally; therefore, in the actual application of the VOC monitoring equipment, it is necessary to remove the water vapor in the sample gas; and the existing VOC monitoring equipment usually uses a nanometer tube (nafion tube, polymer material) to remove the sample gas. For the water vapor in the gas, for the common hydrocarbon VOCs, the water removal effect of the nanometer tube is better; however, for the water-soluble VOCs in the sample gas (such as alcohol VOCs that are very soluble in water), usually along with the water vapor If they are removed together, the concentration can be lost up to 80%, which will lead to large errors in the measurement results of VOC monitoring equipment

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