阅读说明：本技术 一种挥发性有机物VOCs多通道在线监测系统 (Volatile organic compounds VOCs multichannel on-line monitoring system ) 是由 芦志强 丁文科 梁龙杨 于 2020-03-20 设计创作，主要内容包括：本发明涉及一种挥发性有机物VOCs多通道在线监测系统,该挥发性有机物VOCs多通道在线监测系统,包括烟气采样探头、预处理系统、吸氢预检定系统和氢火焰离子检测器,所述烟气采样探头设于烟气通道内,对烟气进行采样,烟气采样探头连接预处理系统的样品气进口,预处理系统的样品气出口连接吸氢预检定系统的进口,吸氢预检定系统的出口连接氢火焰离子检测器的样品进口；吸氢预检定系统包括流量计、吸氢单元和余氢检定单元,吸氢单元通过管道连接氢气源；本发明预先通过吸氢预检定系统对乙烯进行加氢反应,对得到的乙烷含量进行检定,通过乙烷检定值对氢火焰离子检测器得到的甲烷含量结果出现的偏差进行校正。(The invention relates to a multi-channel online monitoring system for Volatile Organic Compounds (VOCs), which comprises a flue gas sampling probe, a pretreatment system, a hydrogen absorption pre-detection system and a hydrogen flame ion detector, wherein the flue gas sampling probe is arranged in a flue gas channel and is used for sampling flue gas, the flue gas sampling probe is connected with a sample gas inlet of the pretreatment system, a sample gas outlet of the pretreatment system is connected with an inlet of the hydrogen absorption pre-detection system, and an outlet of the hydrogen absorption pre-detection system is connected with a sample inlet of the hydrogen flame ion detector; the hydrogen absorption pre-determination system comprises a flow meter, a hydrogen absorption unit and a residual hydrogen verification unit, wherein the hydrogen absorption unit is connected with a hydrogen source through a pipeline; according to the invention, a hydrogen absorption pre-verification system is used for carrying out hydrogenation reaction on ethylene in advance, the obtained ethane content is verified, and the ethane verification value is used for correcting the deviation of the methane content result obtained by the hydrogen flame ion detector.)

1. The utility model provides a volatile organic compounds VOCs multichannel on-line monitoring system which characterized in that: the system comprises a flue gas sampling probe, a pretreatment system, a hydrogen absorption pre-detection system and a hydrogen flame ion detector, wherein the flue gas sampling probe is arranged in a flue gas channel and is used for sampling flue gas;

the hydrogen absorption pre-detection system comprises a flow meter, a hydrogen absorption unit and a residual hydrogen detection unit, wherein the hydrogen absorption unit is connected with a hydrogen source through a pipeline, the pipeline is provided with the flow meter for detecting the hydrogen inlet amount entering the hydrogen absorption unit, the outlet of the hydrogen absorption unit is connected with the inlet of the residual hydrogen detection unit, and the outlet of the residual hydrogen detection unit is connected with the inlet of the hydrogen flame ion detector.

2. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the carrier gas is nitrogen.

3. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the pretreatment system comprises a mixer, a quantitative ring, a pretreatment chromatographic column and a methane chromatographic column, wherein a sample gas inlet of the mixer is connected with a flue gas sampling probe, a carrier gas inlet of the mixer is connected with a carrier gas source, a sample gas outlet of the mixer is connected with an inlet of the quantitative ring, an outlet of the quantitative ring is connected with an inlet of the pretreatment chromatographic column, an outlet of the pretreatment chromatographic column is connected with an inlet of the methane chromatographic column, and an outlet of the methane chromatographic column is connected with a hydrogen absorption pre-detection system.

4. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the hydrogen absorption unit is a high-pressure reaction kettle.

5. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the residual hydrogen verification unit is a replacement tank, a mixed gas inlet of the replacement tank is connected with an outlet of the hydrogen absorption unit, a replacement gas inlet is connected with a nitrogen source, a first gas outlet is connected with hydrogen detection equipment, a second gas outlet is connected with a hydrogen flame ion detector, methane and ethane are liquefied by pressurizing and cooling, the gaseous state of hydrogen is kept by using the boiling point difference, then nitrogen is introduced to replace the internal hydrogen, and the amount of the replaced hydrogen is verified by the hydrogen detection equipment.

6. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the residual hydrogen verification unit is a cold trap, an air inlet of the cold trap is connected with an outlet of the hydrogen absorption unit, a carrier gas inlet is connected with a nitrogen source, a first air outlet is connected with hydrogen detection equipment, a second air outlet is connected with a hydrogen flame ion detector, hydrogen is separated by the cold trap through melting point difference, methane and ethane are retained, then the separated hydrogen amount is verified through the hydrogen detection equipment, and then the temperature is raised to discharge the methane and the ethane to the hydrogen flame ion detector through the second air outlet.

7. The multi-channel online monitoring system for VOCs according to claim 1, wherein: the mixer is provided with a backflushing inlet and a backflushing outlet, the backflushing inlet is connected with a backflushing air source, and the backflushing outlet is connected with an exhaust pipeline.

Technical Field

The invention belongs to the technical field of volatile organic compound monitoring, and particularly relates to a Volatile Organic Compound (VOCs) multichannel online monitoring system.

Background

Volatile Organic Compounds (VOCs) are important precursors for forming secondary pollutants such as fine particulate matters (PM2.5) and ozone (O3), and further cause atmospheric environmental problems such as dust haze and photochemical smog. With the rapid development of industrialization and urbanization in China and the continuous increase of energy consumption, regional compound air pollution characterized by PM2.5 is increasingly prominent, the frequency of the phenomenon of heavy air pollution in the region is increased in a large range, the sustainable development of social economy is seriously restricted, and the health of people is threatened. In order to fundamentally solve the pollution problems of PM2.5, O3 and the like, the quality of the atmospheric environment is improved practically. However, the basic of prevention and control of VOCs pollution in China is weak, and the problems of unclear discharge base number, unsound regulation standards, lagged control technology application, inadequate environmental supervision and the like exist. Meanwhile, the difficulty in establishing a VOCs pollution control system is high due to the fact that VOCs are complex in emission source, various in emission form and various in material variety. The existing VOCs online monitoring system detects the content of total hydrocarbons, methane and benzene respectively through the mode of multi-channel separation detection, and needs to separate the methane in a methane content detection channel, and the separated methane purity is influenced by the ethylene due to the close boiling points of the methane and the ethylene during separation, and finally the deviation appears in the result of the methane content obtained by the hydrogen flame ion detector.

Disclosure of Invention

The invention aims to solve the problems and provide a multichannel online monitoring system for Volatile Organic Compounds (VOCs) for correcting deviation of a methane content result obtained by a hydrogen flame ion detector.

The invention realizes the purpose through the following technical scheme:

a multichannel online monitoring system for Volatile Organic Compounds (VOCs) comprises a flue gas sampling probe, a pretreatment system, a hydrogen absorption pre-detection system and a hydrogen flame ion detector, wherein the flue gas sampling probe is arranged in a flue gas channel and is used for sampling flue gas;

the hydrogen absorption pre-detection system comprises a flow meter, a hydrogen absorption unit and a residual hydrogen detection unit, wherein the hydrogen absorption unit is connected with a hydrogen source through a pipeline, the pipeline is provided with the flow meter for detecting the hydrogen inlet amount entering the hydrogen absorption unit, the outlet of the hydrogen absorption unit is connected with the inlet of the residual hydrogen detection unit, and the outlet of the residual hydrogen detection unit is connected with the inlet of the hydrogen flame ion detector.

As a further optimization of the invention, the carrier gas is nitrogen.

As a further optimization scheme of the invention, the pretreatment system comprises a mixer, a quantitative ring, a pretreatment chromatographic column and a methane chromatographic column, wherein a sample gas inlet of the mixer is connected with a flue gas sampling probe, a carrier gas inlet of the mixer is connected with a carrier gas source, a sample gas outlet of the mixer is connected with an inlet of the quantitative ring, an outlet of the quantitative ring is connected with an inlet of the pretreatment chromatographic column, an outlet of the pretreatment chromatographic column is connected with an inlet of the methane chromatographic column, and an outlet of the methane chromatographic column is connected with a hydrogen absorption pre-detection system.

As a further optimization scheme of the invention, the hydrogen absorption unit is a high-pressure reaction kettle.

As a further optimization scheme of the invention, the residual hydrogen verification unit is a replacement tank, a mixed gas inlet of the replacement tank is connected with an outlet of the hydrogen absorption unit, a replacement gas inlet is connected with a nitrogen source, a first gas outlet is connected with hydrogen detection equipment, a second gas outlet is connected with a hydrogen flame ion detector, methane and ethane are liquefied by pressurizing and cooling, the gas state of hydrogen is maintained by utilizing the boiling point difference, then nitrogen is introduced to replace the internal hydrogen, and the amount of the replaced hydrogen is verified by the hydrogen detection equipment.

As a further optimization scheme of the invention, the residual hydrogen verification unit is a cold trap, a gas inlet of the cold trap is connected with an outlet of the hydrogen absorption unit, a carrier gas inlet is connected with a nitrogen source, a first gas outlet is connected with hydrogen detection equipment, a second gas outlet is connected with a hydrogen flame ion detector, hydrogen is separated by the cold trap by utilizing melting point difference, methane and ethane are retained, then the amount of the separated hydrogen is verified by the hydrogen detection equipment, and then the temperature is raised, and the methane and the ethane are discharged to the hydrogen flame ion detector through the second gas outlet.

As a further optimization scheme of the invention, a back-flushing inlet and a back-flushing outlet are arranged on the mixer, the back-flushing inlet is connected with a back-flushing air source, and the back-flushing outlet is connected with an exhaust pipeline.

The invention has the beneficial effects that:

1) the method comprises the steps of carrying out hydrogenation reaction on ethylene in advance through a hydrogen absorption pre-verification system, verifying the obtained ethane content, and correcting the deviation of a methane content result obtained by a hydrogen flame ion detector through the ethane verification value;

2) the invention skillfully utilizes the saturation difference of methane and ethylene to detect the non-methane quantity by hydrogenation, and corrects the methane content result obtained by the hydrogen flame ion detector to obtain an accurate result.

Drawings

FIG. 1 is a schematic diagram of a system according to the present invention in a first embodiment;

FIG. 2 is a schematic view showing the structure of a hydrogen absorption pre-determination system according to the present invention in accordance with one embodiment;

fig. 3 is a schematic structural diagram of the system of the present invention in the third embodiment.

Detailed Description

The present application will now be described in further detail with reference to the drawings, it should be noted that the following detailed description is given for illustrative purposes only and is not to be construed as limiting the scope of the present application, as those skilled in the art will be able to make numerous insubstantial modifications and adaptations to the present application based on the above disclosure.