Device for enriching and detecting dioxin

Abstract

The utility model relates to a device for enriching and detecting dioxin. The device comprises a particle enriching system, a gas-phase dioxin enriching system and a power system which are sequentially connected through sampling pipes, a heat tracing band is arranged on the sampling pipe at the upstream of the gas-phase dioxin enrichment system; the gas-phase dioxin enrichment system comprises an organic membrane containing a porous material, the thickness of the organic membrane containing the porous material is 5-10 mm, and the aperture of the organic membrane containing the porous material is 1.2-1.5 nm; dioxin in a solid phase is completely intercepted and collected through the particle enrichment system, so that the loss is reduced; according to the gas-phase dioxin enrichment system, dioxin molecules can be effectively enriched, dioxin can be intercepted and filtered, so that fine dioxin particles are suspended in gas, gas sampling can be performed during determination, convenience and rapidness are realized, pretreatment procedures are reduced, other substances with small molecular dynamic diameters are filtered out, and the difficulty and cost of subsequent detection are effectively reduced.

Description

Technical Field

[0001] The utility model relates to a device for enriching and detecting dioxins, belonging to the technical field of environmental monitoring. Background Art

[0002] Industries such as waste incineration, iron and steel, and non-ferrous metals will generate a large amount of dioxin pollutants during daily industrial production. Dioxins are polychlorinated oxygenated planar aromatic hydrocarbons, belonging to a class of highly toxic substances, with strong carcinogenic and teratogenic properties, and having a serious impact on the skin and mucous membranes, nervous system, endocrine system, etc. Therefore, it is necessary to effectively monitor and prevent the generated dioxins.

[0003] At present, dioxin detection methods include chromatographic mass spectrometry detection method, biological method, and indirect detection method. Among them, the chromatographic mass spectrometry detection method is the standard method, and the steps include collecting dioxins in flue gas with a sampler containing a fiber filter membrane and XAD-2 resin, and performing pretreatment such as extraction, concentration, purification, and nitrogen blowing concentration, and finally entering a high-performance chromatography / high-performance mass spectrometry instrument for detection. The biological method is characterized by a short analysis period, low analysis cost, and the ability to parallelly measure a large number of samples, but the biological detection method cannot determine the specific components of dioxins, and at the same time cannot exclude the interference of other aromatic receptors. The indirect detection method is to estimate the dioxin concentration by using dioxin indicators or associated substances in flue gas, including chlorobenzene, phenol, polycyclic aromatic hydrocarbons, and small molecule compounds such as carbon monoxide and hydrogen chloride. The concentration of the above substances is at least 100-1000 times that of dioxin pollutants, which is easier to detect, but requires a large amount of actual detection data, increasing the difficulty of indirectly detecting dioxins with indicators.

[0004] For example, patent publication number CN114034538A discloses an enrichment device and usage method for dioxin detection, including a machine shell, a particle filtration shell, a storage bottle, and an air pump. This device filters impurities in combustion exhaust gas through a filtration mechanism, effectively collects dioxins attached to impurity particles, and at the same time absorbs dioxins in the exhaust gas through a storage bottle containing an organic solvent, realizing the dual collection of solid and gaseous dioxins. Compared with traditional dioxin collection equipment, the collection rate of dioxins is improved;

[0005] When using an organic solvent to absorb dioxins in the solid phase and gas phase, organic substances such as chlorobenzene, phenol, and polycyclic aromatic hydrocarbons will be absorbed incidentally, and the concentration is much higher than that of dioxins, causing interference to the accurate determination of dioxins, and at the same time making the subsequent detection pretreatment of dioxins cumbersome.

[0006] For example, patent publication number CN115825310A discloses a method for detecting dioxins in waste incineration flue gas based on single substances or multiple indicators. First, an indicator correlation model is constructed that correlates the peak area of the indicator with the dioxin concentration value. Then, characteristic data of the indicator is collected to obtain the peak area within the time-of-flight interval. Finally, the peak area of the indicator is substituted into the correlation model for calculation to obtain the dioxin concentration value. This method ionizes the indicator through continuous injection of standard gases or liquids, laser wavelength scanning, etc. to obtain parameter information such as the laser ionization wavelength and time-of-flight of the corresponding indicator, shortening the data detection cycle and improving the detection efficiency;

[0007] To achieve accurate prediction, a large amount of actual test data is required to construct an accurate mathematical model relationship between the indicator and the actual dioxin concentration.

[0008] The above existing technologies cannot selectively enrich dioxins, resulting in the collection of all organic pollutants in the flue gas, leading to complex subsequent dioxin detection procedures and increased costs. Utility Model Content

[0009] The purpose of this utility model is to provide a device for enriching and detecting dioxins to solve the problems raised in the above background technology.

[0010] The technical solution of this utility model is as follows:

[0011] A device for enriching and detecting dioxins includes a particle enrichment system, a gas-phase dioxin enrichment system, and a power system connected in sequence through a sampling pipe;

[0012] A heating tape is provided on the sampling pipe upstream of the gas-phase dioxin enrichment system;

[0013] The gas-phase dioxin enrichment system includes an organic membrane containing a porous material;

[0014] The organic membrane containing a porous material is used to enrich dioxins with a molecular kinetic diameter above that of single benzene and below that of molecules with 3 benzene rings.

[0015] Preferably, the thickness of the organic membrane containing a porous material is 5 - 10 mm.

[0016] Preferably, the pore diameter of the organic membrane containing a porous material is 1.2 - 1.5 nm.

[0017] Preferably, the porous material is one or several of MOFs, zeolite molecular sieves, carbon molecular sieves, mesoporous silica, carbon nanotubes; the particle size of the porous material is 10 - 300 nm; the proportion of the porous material in the organic membrane is 10% - 30%.

[0018] Preferably, the organic membrane is one or more of polyvinyl alcohol, polydimethylsiloxane, polyimide, polysulfone, tetrabromobisphenol A polycarbonate, cellulose acetate, and silicone rubber.

[0019] The gas-phase dioxin enrichment system further includes a box body and a plurality of flow guiding plates. The organic membrane containing the porous material is arranged in the box body, and the plurality of flow guiding plates are located between the air inlet of the box body and the organic membrane containing the porous material.

[0020] Preferably, the distance between two adjacent flow guiding plates gradually increases from the air inlet of the box body to the organic membrane containing the porous material.

[0021] Preferably, the plurality of flow guiding plates are in an arc structure and are symmetrically arranged, and the two symmetrically arranged flow guiding plates form an "eight" character structure.

[0022] Preferably, a heat tracing tape is arranged on the box body.

[0023] Preferably, the particle enrichment system includes a water storage bottle, an air inlet pipe, and an air outlet pipe. Deionized water is arranged in the water storage bottle. The air outlet end of the air inlet pipe extends below the liquid level of the deionized water in the water storage bottle, and the air inlet end of the air outlet pipe is located above the liquid level of the deionized water in the water storage bottle.

[0024] Preferably, the particle enrichment system includes a filter with a gradually decreasing inner diameter along the gas flow direction.

[0025] The utility model has the following beneficial effects:

[0026] All the dioxins in the solid phase are intercepted and collected by the particle enrichment system, reducing losses; the gas-phase dioxin enrichment system can effectively enrich dioxin molecules, intercept and filter dioxins, make dioxin fine particles suspended in the gas, and gas sampling can be carried out during measurement, which is convenient and fast, reduces the pretreatment process, and filters out other substances with small molecular kinetic diameters, effectively reducing the difficulty and cost of subsequent detection. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of the first embodiment of the utility model;

[0028] Figure 2 It is a schematic structural diagram of the second embodiment of the utility model.

[0029] The reference numerals in the drawings are represented as:

[0030] 1. Sampling tube; 2. Particle enrichment system; 3. Gas-phase dioxin enrichment system; 31. Flow guiding plate; 4. Power system. Detailed Embodiments

[0031] The present utility model will be described in detail below with reference to the drawings and specific embodiments.

[0032] Example 1:

[0033] A device for enriching and detecting dioxins, as Figure 1 shown:

[0034] It mainly includes three parts, namely the particle enrichment system 2, the gaseous dioxin enrichment system 3, and the power system 4. The power system 4 is located at the rear end of the device to attract the flue gas and transport it forward. After being collected by the sampling pipe 1, the flue gas first enters the particle enrichment system 2, and the dust particles in the flue gas, together with the dioxins in the dust, are collected in water; the cleaned flue gas is transported through the sampling pipe 1 and enters the gaseous dioxin enrichment system 3, where dioxins are intercepted through the steric effect. Finally, the flue gas without dioxins is evacuated by suction.

[0035] The sampling pipe 1 is equipped with a heating tape and a temperature control device. The temperature of the sampling pipe 1 is maintained at a set temperature (such as 435 °C) through the temperature control device to prevent dioxins from condensing and accumulating in the sampling pipe 1. The sampling pipe 1 is made of 316L stainless steel. The heating tape can be a strip-shaped resistance heater, which is laid on the outer wall of the sampling pipe 1 to convert electrical energy into heat energy.

[0036] The particle enrichment system 2 includes a water storage bottle. The water storage bottle uses a Meng's bottle, which is made of glass, with a volume of 1 - 1.5 L and contains 1 / 3 - 1 / 2 deionized water. It is used to wash the dust particles in the flue gas. During the collection process, the flue gas enters the water from the inlet of the long channel (air inlet pipe) and flows out of the Meng's bottle from the outlet of the short channel (air outlet pipe).

[0037] The gaseous dioxin enrichment system 3 includes a cuboid box with dimensions of 300×200×300 mm. The box is provided with a heating tape. Inside the box, there is an organic membrane with a cross-sectional area of 200×300 mm containing porous materials. The thickness of the organic membrane containing porous materials is 5 - 10 mm; the porous materials are one or more of MOFs, zeolite molecular sieves, carbon molecular sieves, mesoporous silica, and carbon nanotubes, which have a regular pore structure and a large specific surface area, can form a continuous gas passage inside the membrane, and account for 10% - 30% of the mass of the organic membrane, with a particle size of 10 - 300 nm; the organic membrane is one or more of polyvinyl alcohol, polydimethylsiloxane, polyimide, polysulfone, tetrabromo polycarbonate, cellulose acetate, and silicone rubber.

[0038] The pore diameter of the organic membrane containing porous materials is controlled to be 1.2 - 1.5 nm, which is larger than the molecular kinetic diameter of small molecule gases and monobenzenes below 0.8 nm, but smaller than the molecular kinetic diameter of dioxins close to 3 benzene rings.

[0039] There are also multiple flow guiding plates 31 arranged inside the box body. The flue gas input from the air inlet end of the box body is evenly guided to the organic membrane containing porous materials through the flow guiding plates 31. The flow guiding plates 31 are made of stainless steel and have an arc-shaped structure. As Figure 1 shown, the four groups of flow guiding plates 31 are symmetrically distributed on the upper and lower sides. Two symmetrical flow guiding plates 31 form an "eight" - shaped structure. The flow guiding plates 31 with the "eight" - shaped structure are conducive to gathering more flue gas in the middle, and the remaining flue gas is dispersed on both sides.

[0040] The power system 4 is a suction pump with a maximum flow rate of 100 L / min and a maximum vacuum degree of 10 kPa.

[0041] Working principle:

[0042] The waste incineration flue gas contains a large amount of dioxins, nitrogen oxides, carbon oxides, and dust particles, etc. Among them, the particle size of the dust particles is at least in the micron level. Dioxins, as polycyclic benzene substances, have a particle size greater than 3 nm, which is much larger than the components such as chlorobenzene, chlorophenol, CO2, SO2, N2, O2, etc. in the flue gas.

[0043] The flue gas enters the particle enrichment system 2 through the sampling pipe 1 with a heating tape. The dust in the flue gas remains in the water storage bottle after being washed by water, including most of the dioxins condensed due to temperature reduction. The escaped dioxins enter the gas - phase dioxin enrichment system 3 along with the flue gas. After being filtered through the organic membrane containing porous materials, the dioxins are retained in the gas - phase dioxin enrichment system 3, and the remaining flue gas is discharged.

[0044] The particle enrichment system 2 is not equipped with a heating tape and has a relatively low temperature. Dioxins can be condensed to form solids and adhere to the deionized water for cleaning through temperature reduction, reducing the loss.

[0045] The deionized water after cleaning can be extracted with n - hexane, and the extraction solution is used for analyzing the dioxin content by machine. The dioxins in the gas - phase dioxin enrichment system 3 can be directly sampled as gas and analyzed for the dioxin content by machine.

[0046] Example two: As Figure 2 shown, it includes all the content of Example one, and the differences are as follows:

[0047] The particle enrichment system 2 includes a machine body and a filter with a pore size of about 200 nm arranged inside the machine body. The filter uses one of ceramic filters, metal filters, activated carbon, and fiber filter membranes as the filter material. Its function is to filter and collect the particulate matter in the flue gas to prevent it from affecting the subsequent gas - phase dioxin enrichment system 3. A heating tape is arranged on the machine body. The inner diameter of the cross - section of the filter gradually decreases along the gas flow direction.

[0048] Another embodiment of the flow guiding plate 31, as Figure 2As shown in the figure, the distance between two adjacent flow deflectors 31 gradually increases from the air inlet of the box body to the organic membrane containing porous materials. The air inlet diameter of the box body is relatively small. Through the above-mentioned multiple flow deflectors 31, the flue gas is evenly transported to each part of the organic membrane with a large area and containing porous materials.

[0049] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A device for enriching and detecting dioxins, characterized in that: It includes a particulate enrichment system (2), a gaseous dioxin enrichment system (3) and a power system (4) connected in sequence through a sampling pipe (1); A heat tracing tape is provided on the sampling pipe (1) upstream of the gaseous dioxin enrichment system (3); The gaseous dioxin enrichment system (3) includes an organic membrane containing a porous material; The organic membrane containing a porous material is used to enrich dioxins with a molecular kinetic diameter above that of monobenzene molecules and below that of molecules with three benzene rings.

2. The device for enriching and detecting dioxin according to claim 1, wherein: The pore diameter of the organic membrane containing a porous material is 1.2 - 1.5 nm.

3. The device for enriching and detecting dioxin according to claim 1, characterized in that: The thickness of the organic membrane containing a porous material is 5 - 10 mm.

4. The device for enriching and detecting dioxin according to claim 1, characterized in that: The gaseous dioxin enrichment system (3) further includes a box body and a plurality of flow guiding plates (31). The organic membrane containing a porous material is arranged in the box body, and the plurality of flow guiding plates (31) are located between the air inlet of the box body and the organic membrane containing a porous material.

5. The device for enriching and detecting dioxin according to claim 4, characterized in that: The distance between two adjacent flow guiding plates (31) gradually increases from the air inlet of the box body towards the organic membrane containing a porous material.

6. The device for enriching and detecting dioxin according to claim 4, characterized in that: The plurality of flow guiding plates (31) are in an arc structure and are symmetrically arranged, and two symmetrically arranged flow guiding plates (31) form an "eight" - shaped structure.

7. The device for enriching and detecting dioxin according to claim 4, characterized in that: A heat tracing tape is provided on the box body.

8. The device for enriching and detecting dioxin according to claim 1, wherein: The particulate enrichment system (2) includes a water storage bottle, an air inlet pipe and an air outlet pipe. Deionized water is provided in the water storage bottle. The air outlet end of the air inlet pipe extends below the liquid level of the deionized water in the water storage bottle, and the air inlet end of the air outlet pipe is above the liquid level of the deionized water in the water storage bottle.

9. The device for enriching and detecting dioxin according to claim 1, wherein: The particulate enrichment system (2) includes a filter with an inner diameter gradually decreasing along the gas flow direction.

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