Two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on air purification

Abstract

The utility model relates to the field of environmental analysis, in particular to a two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on purified air, which comprises a sampling pipeline, a reference pipeline, a gas carrying pipeline and an analysis pipeline, the four-way valve B is sequentially connected with a flowmeter, a buffer tank and a vacuum pump; the reference pipeline is provided with a mercury filter A which is connected with a three-way valve A and then connected into a four-way valve A; the carrier gas pipeline is provided with an air compressor, is sequentially connected with a filter, a nitrogen-oxygen separator, a mercury filter B and a flow controller and then is connected into a four-way valve A; and the analysis pipeline is led out from the four-way valve B to be connected into the pure gold trapping pipe, and is connected with the atomic fluorescence analyzer after passing through the three-way valve B. The device disclosed by the utility model can realize continuous analysis of atmospheric mercury, effectively delays passivation of the trapping pipe, is not limited by the use of high-purity argon, and improves the stability and the accuracy of an analysis result while reducing the cost.

Description

Technical Field

[0001] The utility model relates to the field of environmental analysis, in particular to a two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on purified air. Background Art

[0002] Mercury (Hg) is a toxic heavy metal pollutant and one of the most toxic heavy metal elements in the environment. Mercury and its compounds can be absorbed through the human respiratory tract, digestive tract, and skin. Depending on the amount ingested, it can cause acute or chronic mercury poisoning, severely damaging the central nervous system, liver, and kidney function.

[0003] Whether soluble or sparingly soluble, some mercury compounds volatilize into the atmosphere. Mercury can also be released into the atmosphere through transpiration from soil and plants, and mercury in the gas phase can transfer to liquid and solid phases. Furthermore, mercury has strong cohesive forces and is stable in air, but it evaporates easily. Mercury vapor and its compounds are highly toxic. Therefore, monitoring atmospheric mercury levels has become a key focus of environmental monitoring efforts.

[0004] In the process of monitoring atmospheric mercury content, the existing technical solution mainly uses a gold capture tube to sample the atmosphere, complete the mercury adsorption operation, then heat it to thermally desorb the mercury, and then transport the mercury into a large instrument such as an atomic fluorescence analyzer for analysis under the drive of a carrier gas. The existing technical solution has the following main drawbacks:

[0005] (1) Low work efficiency. In the existing technical solutions, adsorption and thermal desorption cannot be carried out simultaneously in the atmospheric sampling process. The atmospheric sample needs to be heated for desorption after adsorption, and after heating and desorption, it is necessary to wait for the gold capture tube to cool down before adsorption can be carried out, resulting in low analysis efficiency.

[0006] (2) High analysis cost. Using high-purity argon as carrier gas results in high analysis cost, inconvenience in use and replacement, and high requirements for equipment and instruments due to the properties of argon itself.

[0007] (3) Core components are prone to passivation. The gold capture tube, as the core component of the existing technical solution, is easily affected by impurities, acidic components, chlorine-containing components, moisture, etc. in the air during use of the existing technical solution, which can easily cause the gold capture tube to passivate in a short period of time, thereby seriously affecting the accuracy of the analysis results. In severe cases, it may even cause the gold capture tube to become inactivated, leading to failure of the analysis.

[0008] In summary, monitoring of mercury content in the atmosphere is the focus of environmental monitoring work, and overcoming the low efficiency of analysis, high analysis cost, and easy passivation of core components in existing technical solutions has become a problem that needs to be solved urgently. Summary of the Invention

[0009] (1) Technical issues to be resolved

[0010] The technical problem to be solved by the utility model is to provide a two-stage adsorption-thermal desorption continuous analysis device for atmospheric mercury based on purified air, so as to solve the problems of low analysis efficiency, high analysis cost and easy passivation of core components encountered in the process of monitoring atmospheric mercury content in actual work, thereby providing a solution for continuous monitoring of atmospheric mercury content, improving the accuracy of monitoring results, improving work efficiency and reducing analysis costs.

[0011] (2) Technical solution

[0012] In order to solve the above problems, the present invention is implemented through the following technical solutions.

[0013] A two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on purified air, characterized in that it includes: a sampling pipeline, a reference pipeline, a carrier gas pipeline, and an analysis pipeline: the sampling pipeline is provided with a gold sand collection tube A and a gold sand collection tube B, the gold sand collection tube A and the gold sand collection tube B are respectively connected to a four-way valve A and a four-way valve B on the left and right, the four-way valve A is connected to a three-way valve A, the three-way valve A is connected to the injection port, and the four-way valve B is sequentially connected to a flow meter, a buffer tank, a diaphragm pump, and an exhaust port B. ; The reference pipeline is provided with a mercury filter A, one end of the mercury filter A is connected to the reference injection port, and the other end is connected to the three-way valve A and then connected to the four-way valve A; the carrier gas pipeline is provided with an air compressor, and is connected to the filter, nitrogen and oxygen separator, mercury filter B, and flow controller in sequence and then connected to the four-way valve A; the analysis pipeline is led out from the four-way valve B and connected to the pure gold capture tube, and is connected to the atomic fluorescence analyzer after passing through the three-way valve B, and finally connected to the exhaust port A. The three-way valve B is provided with an exhaust port.

[0014] According to the present utility model, it is characterized in that when the sampling pipeline is working, in the first stage, the three-way valve A, the four-way valve A and the four-way valve B are adjusted to connect the sampling port, the three-way valve A, the four-way valve A, the gold sand collection tube A, the four-way valve B, the flow meter, the buffer tank, the diaphragm pump and the exhaust port B in sequence; in the second stage, the three-way valve A, the four-way valve A and the four-way valve B are adjusted to connect the sampling port, the three-way valve A, the four-way valve A, the gold sand collection tube B, the four-way valve B, the flow meter, the buffer tank, the diaphragm pump and the exhaust port B; the first stage and the second stage are performed alternately, and the atmospheric sample is collected from the sampling port under the action of the diaphragm pump, and the adsorption operation is completed in the gold sand collection tube A or the gold sand collection tube B under low temperature conditions; and a thermal desorption operation is performed when the gold sand collection tube A or the gold sand collection tube B is heated.

[0015] According to the present utility model, it is characterized in that when the reference pipeline is working, the three-way valve A and the four-way valve A are adjusted to connect the reference inlet, the mercury filter A, the three-way valve A, the four-way valve A in sequence, and then pass through the gold sand collection tube A or the gold sand collection tube B and connect with the four-way valve B, the flow meter, the buffer tank, the diaphragm pump, and the exhaust port B in sequence; under the action of the diaphragm pump, the atmospheric sample is collected from the reference inlet, and the mercury in the atmospheric sample is filtered out through the mercury filter A to generate a reference sample.

[0016] According to the present utility model, it is characterized in that when the carrier gas pipeline is working, the four-way valve A and the four-way valve B are adjusted to connect the air inlet, the air compressor, the filter, the nitrogen and oxygen separator, the mercury filter B, the flow controller, and the four-way valve A in sequence. After the external air passes through the filter, the nitrogen and oxygen separator, and the mercury filter B in sequence, it is respectively subjected to impurity removal, deoxidation, and mercury removal treatment to generate purified air as the carrier gas.

[0017] According to the present invention, it is characterized in that when the analysis pipeline is working, the four-way valve B and the three-way valve B are adjusted to connect the four-way valve B, the pure gold capture tube, the three-way valve B, and the atomic fluorescence analyzer in sequence, and the mercury element in the atmospheric sample is analyzed by the atomic fluorescence analyzer under the drive of the carrier gas, and finally the exhaust gas is discharged through the exhaust port A; the adsorption operation is completed in the pure gold capture tube under low temperature conditions; and the thermal desorption operation is performed when the pure gold capture tube is heated.

[0018] According to the present invention, it is characterized in that the device first performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-reference analysis operations: adjust the three-way valve A, the four-way valve A and the four-way valve B, and connect the reference inlet, the mercury filter A, the three-way valve A, the four-way valve A, the gold sand collection tube A, the four-way valve B, the flow meter, the buffer tank, the diaphragm pump, and the exhaust port B in sequence, and complete the reference sample collection and adsorption operations under the action of the diaphragm pump; then adjust the three-way valve A, the four-way valve A, the four-way valve B and the three-way valve B, and connect the air inlet, the air compressor, the filter, The nitrogen and oxygen separator, the mercury filter B, the flow controller, the four-way valve A, the gold sand capture tube A, the four-way valve B, the pure gold capture tube, and the three-way valve B are used. The gold sand capture tube A is heated to perform a thermal desorption operation of the reference sample. Driven by the carrier gas, a secondary adsorption operation of the reference sample is performed in the pure gold capture tube, and the dead volume is discharged through the exhaust port of the three-way valve B. Finally, the exhaust port of the three-way valve B is closed, the pure gold capture tube is heated to perform a secondary thermal desorption operation of the reference sample, and driven by the carrier gas, the atomic fluorescence analyzer performs a reference analysis on the reference sample, and the exhaust gas is discharged through the exhaust port A.

[0019] According to the utility model, it is characterized in that when the device performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations, both the gold sand collection tube A and the gold sand collection tube B can be used, and the four-way valve A and the four-way valve B can be adjusted so that the gold sand collection tube A and the gold sand collection tube B work alternately when the device performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations.

[0020] According to the present invention, it is characterized in that the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations: adjust the three-way valve A, the four-way valve A and the four-way valve B, and sequentially connect the sample inlet, the three-way valve A, the four-way valve A, the gold sand collection tube A, the four-way valve B, the flow meter, the buffer tank, the diaphragm pump, and the exhaust port B, and complete the atmospheric sample collection and adsorption operations under the action of the diaphragm pump; then adjust the three-way valve A, the four-way valve A, the four-way valve B and the three-way valve B, and sequentially connect the air inlet, the air compressor, the filter, the nitrogen and oxygen separator , the mercury filter B, the flow controller, the four-way valve A, the gold sand capture tube A, the four-way valve B, the pure gold capture tube and the three-way valve B, and heating the gold sand capture tube A to perform a thermal desorption operation of the atmospheric sample. Driven by the carrier gas, a secondary adsorption operation of the atmospheric sample is performed in the pure gold capture tube, and the dead volume is discharged through the exhaust port of the three-way valve B; finally, the exhaust port of the three-way valve B is closed, the pure gold capture tube is heated to perform a secondary thermal desorption operation of the atmospheric sample, and driven by the carrier gas, the atomic fluorescence analyzer analyzes the mercury element in the atmospheric sample, and the exhaust gas is discharged through the exhaust port A.

[0021] According to the present utility model, it is characterized in that when the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations, both the gold sand collection tube A and the gold sand collection tube B can be used, and the four-way valve A and the four-way valve B can be adjusted so that the gold sand collection tube A and the gold sand collection tube B work alternately when the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations, thereby realizing continuous collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations of the atmospheric sample.

[0022] (3) Beneficial effects

[0023] The utility model provides a two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on purified air. The above technical solution of the utility model has the following beneficial effects.

[0024] (1) Realize the continuous operation of the atmospheric mercury monitoring process to improve work efficiency. In view of the problem that the adsorption and thermal desorption of the atmospheric sampling process cannot be carried out simultaneously in the existing technical solutions, which leads to low analysis efficiency, the utility model adopts an operation mode combining double gold sand capture tubes and pure gold capture tubes. The gold sand capture tube A and the gold sand capture tube B work alternately during the atmospheric sampling process to collect and adsorb atmospheric mercury samples: In the first step, the gold sand capture tube A cools down to adsorb, and the gold sand capture tube B heats to desorb. At this time, the pure gold capture tube performs secondary adsorption and secondary thermal desorption on the sample from the gold sand capture tube B, and combines with the atomic fluorescence analyzer to analyze the atmospheric mercury. Mercury is analyzed and detected; in the second step, the gold sand capture tube A is heated for desorption and the pure gold capture tube B is cooled for adsorption. At this time, the pure gold capture tube performs secondary adsorption and secondary thermal desorption on the sample from the gold sand capture tube A, and combines with the atomic fluorescence analyzer to analyze and detect atmospheric mercury; this cyclic operation enables the two gold sand capture tubes to work alternately during the atmospheric sampling process, and combines with the secondary adsorption and secondary thermal desorption of the pure gold capture tube to achieve continuous sampling and monitoring analysis of atmospheric mercury, thereby improving the work efficiency of atmospheric mercury monitoring, improving the accuracy of the analysis results, and reducing the cost of analysis work.

[0025] (2) Using purified air as carrier gas to reduce analysis costs. In order to solve the problems of using high-purity argon as carrier gas in the existing technical solutions, which have high analysis costs, high requirements for instruments and equipment, and inconvenience in use, the utility model is equipped with a filter, a nitrogen-oxygen separator, and a mercury filter B in the carrier gas pipeline to filter impurities, oxygen, and mercury in the air respectively, thereby generating purified air, which is used as the carrier gas. The utility model uses purified air as carrier gas, which greatly reduces the analysis cost and is very convenient to use. On the other hand, since the attenuation of the atomic fluorescence analyzer caused by nitrogen is controllable, the influence of nitrogen on the analysis results can be eliminated through post-data processing, that is, it will not have a negative impact on the analysis results. In addition, the utility model uses purified air as carrier gas, which greatly reduces the requirements for instruments and equipment compared to high-purity argon, further reducing the analysis cost.

[0026] (3) The core components are not easy to passivate and the analysis accuracy is high. In view of the problem that the core component of the existing technical solution, namely the gold capture tube, is easily affected by impurities, acidic components, chlorine-containing components, moisture, etc. in the air and passivates in a short period of time, thereby seriously affecting the accuracy of the analysis results and even causing the failure of the analysis work, the utility model adopts a double gold sand capture tube combined with a pure gold capture tube to perform a secondary adsorption-thermal desorption operation in the atmospheric mercury monitoring process. During the primary adsorption-thermal desorption operation performed by the gold sand capture tube, the atmospheric sample is purified and enriched once, and then sent to the pure gold capture tube for the secondary adsorption-thermal desorption operation, thereby providing a high-quality analysis sample for the atomic fluorescence analyzer. Due to the existence of the primary adsorption-thermal desorption process, this process effectively protects the pure gold capture tube, thereby effectively preventing the premature passivation of the core component, thereby further reducing the analysis cost and improving the accuracy of the analysis results.

[0027] In summary, the utility model adopts a double gold sand capture tube combined with a pure gold capture tube, and adopts purified air as the carrier gas, thereby realizing continuous sampling in the atmospheric mercury content monitoring process, and solving the problems of low analysis efficiency, high analysis cost, and easy passivation of core components encountered in the actual work of atmospheric mercury content monitoring, thereby providing an effective solution for continuous monitoring of atmospheric mercury content, reducing analysis costs, improving work efficiency and the accuracy of analysis results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attachment Figure 1 This is a schematic diagram of a continuous analysis device for atmospheric mercury using two-stage adsorption-thermal desorption based on purified air.

[0029] Attachment Figure 1 Middle: 1 sampling port, 2 three-way valve A, 3 four-way valve A, 4 gold sand capture tube A, 5 gold sand capture tube B, 6 four-way valve B, 7 reference sampling port, 8 mercury filter A, 9 flow controller, 10 mercury filter B, 11 pure gold capture tube, 12 three-way valve B, 13 exhaust port, 14 atomic fluorescence analyzer, 15 exhaust port A, 16 air inlet, 17 air compressor, 18 filter, 19 nitrogen and oxygen separator, 20 flow meter, 21 buffer tank, 22 diaphragm pump, 23 exhaust port B.

[0030] Attachment Figure 1 In the figure, the arrow direction represents the gas flow direction. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] As attached Figure 1 A two-stage adsorption-thermal desorption atmospheric mercury continuous analysis device based on purified air is characterized in that it comprises: a sampling pipeline, a reference pipeline, a carrier gas pipeline, and an analysis pipeline: the sampling pipeline is provided with a gold sand collecting tube A (4) and a gold sand collecting tube B (5), the gold sand collecting tube A (4) and the gold sand collecting tube B (5) are respectively connected to a four-way valve A (3) and a four-way valve B (6) on the left and right, the four-way valve A (3) is connected to a three-way valve A (2), the three-way valve A (2) is connected to an injection port (1), and the four-way valve B (6) is connected to a flow meter (20), a buffer tank (21), a diaphragm pump (22), and an exhaust port B (23) in sequence; the reference pipeline is provided with a gold sand collecting tube A (4) and a gold sand collecting tube B (5), the gold sand collecting tube A (4) and the gold sand collecting tube B (5) are respectively connected to a four-way valve A (3) and a four-way valve B (6) on the left and right, the four-way valve A (3) is connected to a three-way valve A (2), the three-way valve A (2) is connected to an injection port (1), and the four-way valve B (6) is connected to a flow meter (20), a buffer tank (21), a diaphragm pump (22), and an exhaust port B (23) in sequence; A mercury filter A (8) is provided, one end of the mercury filter A (8) is connected to the reference injection port (7), and the other end is connected to the three-way valve A (2) and then connected to the four-way valve A (3); the carrier gas pipeline is provided with an air compressor (17), and is sequentially connected to the filter (18), the nitrogen and oxygen separator (19), the mercury filter B (10), the flow controller (9) and then connected to the four-way valve A (3); the analysis pipeline is led out from the four-way valve B (6) and connected to the pure gold capture tube (11), and is connected to the atomic fluorescence analyzer (14) after passing through the three-way valve B (12), and finally connected to the exhaust port A (15), and the three-way valve B (12) is provided with an exhaust port (13).

[0033] According to the utility model, when the sampling pipeline is working, in the first stage, the three-way valve A (2), the four-way valve A (3) and the four-way valve B (6) are adjusted, so as to sequentially connect the sampling port (1), the three-way valve A (2), the four-way valve A (3), the gold sand collecting pipe A (4), the four-way valve B (6), the flow meter (20), the buffer tank (21), the diaphragm pump (22) and the exhaust port B (23); in the second stage, the three-way valve A (2), the four-way valve A (3) and the four-way valve B (6) are adjusted, so as to connect the sampling port (1), The three-way valve A (2), the four-way valve A (3), the gold sand collecting tube B (5), the four-way valve B (6), the flow meter (20), the buffer tank (21), the diaphragm pump (22), and the exhaust port B (23); the first stage and the second stage are performed alternately, and the atmospheric sample is collected from the inlet (1) under the action of the diaphragm pump (22), and the adsorption operation is completed in the gold sand collecting tube A (4) or the gold sand collecting tube B (5) under low temperature conditions; when the gold sand collecting tube A (4) or the gold sand collecting tube B (5) is heated, a thermal desorption operation is performed.

[0034] According to the utility model, when the reference pipeline is in operation, the three-way valve A (2) and the four-way valve A (3) are adjusted to sequentially connect the reference inlet (7), the mercury filter A (8), the three-way valve A (2), and the four-way valve A (3), and then pass through the gold sand collecting tube A (4) or the gold sand collecting tube B (5) and sequentially connect with the four-way valve B (6), the flow meter (20), the buffer tank (21), the diaphragm pump (22), and the exhaust port B (23); under the action of the diaphragm pump (22), the atmospheric sample is collected from the reference inlet (7), and mercury in the atmospheric sample is filtered out through the mercury filter A (8) to generate a reference sample.

[0035] According to the utility model, when the carrier gas pipeline is in operation, the four-way valve A (3) and the four-way valve B (6) are adjusted to sequentially connect the air inlet (16), the air compressor (17), the filter (18), the nitrogen and oxygen separator (19), the mercury filter B (10), the flow controller (9), and the four-way valve A (3). After the outside air passes through the filter (18), the nitrogen and oxygen separator (19), and the mercury filter B (10) in sequence, it is subjected to de-impurity, de-oxidation, and de-mercury treatment, respectively, to generate purified air as the carrier gas.

[0036] According to the utility model, when the analysis pipeline is working, the four-way valve B (6) and the three-way valve B (12) are adjusted to sequentially connect the four-way valve B (6), the pure gold capture tube (11), the three-way valve B (12), and the atomic fluorescence analyzer (14); driven by the carrier gas, the mercury element in the atmospheric sample is analyzed by the atomic fluorescence analyzer (14), and finally the exhaust gas is discharged through the exhaust port A (15); the adsorption operation is completed in the pure gold capture tube (11) under low temperature conditions; and the thermal desorption operation is performed when the pure gold capture tube (11) is heated.

[0037] According to the present invention, the device first performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-reference analysis operations: adjusting the three-way valve A (2), the four-way valve A (3) and the four-way valve B (6), and sequentially connecting the reference injection port (7), the mercury filter A (8), the three-way valve A (2), the four-way valve A (3), the gold sand collection tube A (4), the four-way valve B (6), the flow meter (20), the buffer tank (21), the diaphragm pump (22), and the exhaust port B (23), and completing the reference sample collection and adsorption operations under the action of the diaphragm pump (22); then adjusting the three-way valve A (2), the four-way valve A (3), the four-way valve B (6) and the three-way valve B (12), and sequentially connecting the air inlet (16), the air compressor (17), the filter (18 ), the nitrogen and oxygen separator (19), the mercury filter B (10), the flow controller (9), the four-way valve A (3), the gold sand collecting tube A (4), the four-way valve B (6), the pure gold collecting tube (11), the three-way valve B (12), and heating the gold sand collecting tube A (4) to perform a thermal desorption operation of the reference sample. Driven by the carrier gas, a secondary adsorption operation of the reference sample is performed in the pure gold collecting tube (11), and the dead volume is discharged through the exhaust port (13) of the three-way valve B (12); finally, the exhaust port (13) of the three-way valve B (12) is closed, the pure gold collecting tube (11) is heated to perform a secondary thermal desorption operation of the reference sample, and driven by the carrier gas, the atomic fluorescence analyzer (14) performs a reference analysis on the reference sample, and the exhaust gas is discharged through the exhaust port A (15).

[0038] According to the utility model, when the device performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations, both the gold sand collection tube A (4) and the gold sand collection tube B (6) can be used. By adjusting the four-way valve A (3) and the four-way valve B (4), the gold sand collection tube A (4) and the gold sand collection tube B (5) can be alternately operated when the device performs reference sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operations.

[0039] According to the utility model, the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operation: the three-way valve A (2), the four-way valve A (3) and the four-way valve B (6) are adjusted to sequentially connect the sample inlet (1), the three-way valve A (2), the four-way valve A (3), the gold sand collection tube A (4), the four-way valve B (6), the flow meter (20), the buffer tank (21), the diaphragm pump (22) and the exhaust port B (23), and the atmospheric sample collection and adsorption operation is completed under the action of the diaphragm pump (22); then the three-way valve A (2), the four-way valve A (3), the four-way valve B (6) and the three-way valve B (12) are adjusted to sequentially connect the air inlet (16), the air compressor (17), the filter (18) and the nitrogen and oxygen separator (19), the mercury filter B (10), the flow controller (9), the four-way valve A (3), the gold sand collecting tube A (4), the four-way valve B (6), the pure gold collecting tube (11) and the three-way valve B (12), and heating the gold sand collecting tube A (4) to perform a thermal desorption operation of the atmospheric sample, and under the drive of the carrier gas, perform a secondary adsorption operation of the atmospheric sample in the pure gold collecting tube (11), and discharge the dead volume through the exhaust port (13) of the three-way valve B (12); finally, closing the exhaust port (13) of the three-way valve B (12), heating the pure gold collecting tube (11) to perform a secondary thermal desorption operation of the atmospheric sample, and under the drive of the carrier gas, the atomic fluorescence analyzer (14) analyzes the mercury element in the atmospheric sample, and the exhaust gas is discharged through the exhaust port A (15).

[0040] According to the utility model, when the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operation, both the gold sand collection tube A (4) and the gold sand collection tube B (5) can be used. By adjusting the four-way valve A (3) and the four-way valve B (6), the gold sand collection tube A (4) and the gold sand collection tube B (5) can be alternately operated when the device performs the atmospheric sample collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operation, thereby realizing the continuous collection-adsorption-thermal desorption-secondary adsorption-secondary thermal desorption-analysis operation of the atmospheric sample.

[0041] The utility model adopts an operation mode combining the double gold sand collecting tube and the pure gold collecting tube (11), wherein the gold sand collecting tube A (4) and the gold sand collecting tube B (5) work alternately during the atmospheric sampling process to perform the collection and adsorption process of atmospheric mercury samples: in the first step, the gold sand collecting tube A (4) cools down for adsorption and the gold sand collecting tube B (5) heats for desorption, at which time the pure gold collecting tube (11) performs secondary adsorption and secondary thermal desorption on the sample from the gold sand collecting tube B (5), and analyzes and detects atmospheric mercury in combination with the atomic fluorescence analyzer (14); in the second step, the gold sand collecting tube A (4) cools down for adsorption and the gold sand collecting tube B (5) heats for desorption. The collecting tube A (4) is heated for desorption, and the pure gold collecting tube B (5) is cooled for adsorption. At this time, the pure gold collecting tube (11) performs secondary adsorption and secondary thermal desorption on the sample from the gold sand collecting tube A (4), and combines with the atomic fluorescence analyzer (14) to analyze and detect the atmospheric mercury. Such a cyclic operation enables the two gold sand collecting tubes to work alternately during the atmospheric sampling process, and combines with the secondary adsorption and secondary thermal desorption of the pure gold collecting tube (11) to achieve continuous sampling and monitoring analysis of atmospheric mercury, thereby improving the working efficiency of atmospheric mercury monitoring, improving the accuracy of the analysis results, and reducing the cost of analysis work.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A two-stage adsorption-thermal desorption continuous analysis device for atmospheric mercury based on purified air, comprising a sampling pipeline, a reference pipeline, a carrier gas pipeline, and an analysis pipeline: the sampling pipeline is provided with a gold sand collection tube A and a gold sand collection tube B, the gold sand collection tube A and the gold sand collection tube B are respectively connected to a four-way valve A and a four-way valve B on the left and right, the four-way valve A is connected to a three-way valve A, the three-way valve A is connected to an injection port, and the four-way valve B is sequentially connected to a flow meter, a buffer tank, a diaphragm pump, and an exhaust port B; The reference pipeline is provided with a mercury filter A, one end of which is connected to the reference injection port, and the other end is connected to the three-way valve A and then connected to the four-way valve A; the carrier gas pipeline is provided with an air compressor, and is connected to the filter, nitrogen and oxygen separator, mercury filter B, and flow controller in sequence and then connected to the four-way valve A; the analysis pipeline is led out from the four-way valve B and connected to a pure gold capture tube, connected to an atomic fluorescence analyzer after passing through the three-way valve B, and finally connected to the exhaust port A, and the three-way valve B is provided with an exhaust port.

2. The continuous analysis device for atmospheric mercury based on two-stage adsorption-thermal desorption of purified air according to claim 1, characterized in that: When the reference pipeline is working, the three-way valve A and the four-way valve A are adjusted to connect the reference inlet, the mercury filter A, the three-way valve A, and the four-way valve A in sequence, and then connect with the four-way valve B, the flow meter, the buffer tank, the diaphragm pump, and the exhaust port B in sequence after passing through the gold sand collection tube A or the gold sand collection tube B; under the action of the diaphragm pump, an atmospheric sample is collected from the reference inlet, and mercury in the atmospheric sample is filtered out through the mercury filter A to generate a reference sample.

3. The continuous analysis device for atmospheric mercury based on two-stage adsorption-thermal desorption of purified air according to claim 1, characterized in that: When the carrier gas pipeline is working, the four-way valve A and the four-way valve B are adjusted to connect the air inlet, the air compressor, the filter, the nitrogen and oxygen separator, the mercury filter B, the flow controller, and the four-way valve A in sequence. After the external air passes through the filter, the nitrogen and oxygen separator, and the mercury filter B in sequence, it is respectively subjected to impurity removal, deoxidation, and mercury removal treatment to generate purified air as the carrier gas.

4. The continuous analysis device for atmospheric mercury based on two-stage adsorption-thermal desorption of purified air according to claim 1, characterized in that: When the analysis pipeline is working, the four-way valve B and the three-way valve B are adjusted to connect the four-way valve B, the pure gold capture tube, the three-way valve B, and the atomic fluorescence analyzer in sequence. Driven by the carrier gas, the mercury element in the atmospheric sample is analyzed by the atomic fluorescence analyzer, and finally the exhaust gas is discharged through the exhaust port A; the adsorption operation is completed in the pure gold capture tube under low temperature conditions; and the thermal desorption operation is performed when the pure gold capture tube is heated.

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