Gas detection system

Abstract

The utility model discloses a gas detection system which comprises a drying unit, an adsorption unit and an analysis and detection unit, wherein the drying unit is used for being connected and drying gas to be detected; the adsorption unit is filled with a solid porous adsorption material and is used for adsorbing the gas to be detected; the analysis and detection unit is used for detecting radioactive inert gas in the gas to be detected; the drying unit, the adsorption unit and the analysis and detection unit are connected in sequence. According to the gas detection system disclosed by the utility model, the adsorption unit is filled with the solid porous adsorption material, so that the target gas can be subjected to adsorption treatment and is desorbed to the analysis and detection unit, and the activity concentration of the target gas is detected.

Description

TECHNICAL FIELD

[0001] The utility model relates to nuclear power gas measurement technical field especially relates to a gas detection system. BACKGROUND

[0002] Inert noble gases such as krypton (Kr) and xenon (Xe) are produced in the production of nuclear power plants and the reprocessing of spent fuel, which have certain radioactivity and are easy to volatilize and diffuse, posing a threat to environmental safety. It is crucial for the efficient, safe and sustainable development of nuclear energy to achieve the enrichment and separation of these gases.

[0003] Traditional methods for separating inert gases in nuclear power plants have high energy consumption and low economic benefits. In addition, the activity concentration of some airborne radioactive inert gases in nuclear power plants is lower than the detection limit of gamma-ray spectrum analysis measurement methods, resulting in inaccurate estimates of airborne radioactive inert gases emitted by nuclear power plants, which in turn affects the accuracy of environmental impact assessment results for nuclear power plants. Therefore, it is necessary to optimize the existing analysis and measurement process of nuclear power plants to achieve accurate measurement of activity concentration by enriching and separating airborne radioactive inert gases and to ensure the safety and protection of the environment of nuclear power plants. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide an improved gas detection system.

[0005] The technical solution adopted by the utility model to solve its technical problem is to provide a gas detection system, which includes a drying unit for connecting and drying the measured gas, an adsorption unit filled with solid porous adsorbent material for adsorbing the measured gas, and an analysis and detection unit for detecting radioactive inert gases in the measured gas.

[0006] The drying unit, adsorption unit and analysis and detection unit are connected in sequence.

[0007] In some embodiments, the drying unit includes a drying column and a sample chamber, and the adsorption unit includes a breakthrough column filled with the solid porous adsorbent material.

[0008] The inlet end of the drying column is used to connect the measured gas, the outlet end of the drying column is connected to the sample chamber, and the sample chamber is connected to the inlet end of the breakthrough column through a first pipeline.

[0009] The analysis and detection unit includes a gas detector, and the gas detector is connected to the outlet end of the breakthrough column through a second pipeline.

[0010] In some embodiments, the drying unit includes a drying column and a constant flow pump, and the adsorption unit includes a breakthrough column filled with the solid porous adsorbent material.

[0011] The inlet end of the drying column is connected with a first three-way valve, and the outlet end of the drying column is connected with a second three-way valve.

[0012] The outlet end of the penetrating column is also connected with the to-be-detected gas through a circulating pipeline, so that the to-be-detected gas, the drying column, the constant flow pump and the penetrating column are connected to form a loop.

[0013] In some embodiments, the inlet end of the drying column is connected with a first three-way valve, and the outlet end of the drying column is connected with a second three-way valve.

[0014] In some embodiments, the adsorption unit further comprises a temperature control device, which is arranged corresponding to the penetrating column and is used for heating the penetrating column.

[0015] In some embodiments, the gas detection system further comprises a working gas source for providing working gas, and a fourth pipeline connected between the working gas source and the inlet end of the penetrating column, so that the working gas is introduced into the penetrating column to carry the to-be-detected gas desorbed.

[0016] In some embodiments, the drying unit comprises at least one drying column; and the adsorption unit comprises at least one adsorption column filled with the solid porous adsorption material.

[0017] In some embodiments, the analysis and detection unit comprises a chromatographic column connected with the adsorption column, and a gas analysis and detection device connected with the chromatographic column; or the analysis and detection unit comprises a gas analysis and detection device connected with the adsorption column.

[0018] In some embodiments, the gas detection system further comprises a collection unit connected with the gas analysis and detection device, for collecting the to-be-detected gas.

[0019] The collection unit comprises at least one collection column filled with the solid porous adsorption material.

[0020] In some embodiments, the gas detection system further comprises a purification unit; the purification unit comprises an iodine adsorption column for adsorbing and removing impurities in the to-be-detected gas, and a wet scrubbing device for converting nitrogen oxides in the to-be-detected gas into HNO3; the iodine adsorption column is connected with the inlet end of the drying column, and the wet scrubbing device is connected between the iodine adsorption column and the inlet end of the drying column.

[0021] The gas detection system has the following beneficial effects: the solid porous adsorption material filled in the adsorption unit can adsorb and process the target gas, and the target gas is desorbed / desorbed to the analysis and detection unit, so that the activity concentration of the target gas can be detected. BRIEF DESCRIPTION OF DRAWINGS

[0022] The utility model will be further described below in combination with the drawings and embodiments, in which:

[0023] Figure 1 is the structure schematic diagram of the gas detection system of the first embodiment of the utility model;

[0024] Figure 2 is the structure schematic diagram of the gas detection system of the second embodiment of the utility model;

[0025] Figure 3 is the structure schematic diagram of the gas detection system of the third embodiment of the utility model;

[0026] Figure 4 is the structure schematic diagram of the gas detection system of the fourth embodiment of the utility model. DETAILED DESCRIPTION

[0027] In order to have more clear understanding of the technical features, objects and effects of the utility model, the specific implementation mode of the utility model will be described in detail with reference to the drawings.

[0028] As Figure 1 shown, the gas detection system of the first embodiment of the utility model includes drying unit, adsorption unit and analysis detection unit connected in sequence.

[0029] Among them, the drying unit is used for connecting the measured gas and drying the measured gas. The adsorption unit receives the dried measured gas and adsorbs the measured gas through the solid porous adsorption material filled in itself. The analysis detection unit is used for analyzing and detecting the measured gas, including detecting the type of radioactive inert gas in the measured gas, detecting the activity concentration, etc.

[0030] In Figure 1 the embodiment shown, the drying unit includes drying column 11 and sample cavity 12. The inlet end of drying column 11 is used for connecting the measured gas, and the outlet end of drying column 11 is connected to the inlet end of sample cavity 12 through the connecting pipeline, so that the measured gas can enter sample cavity 12 for temporary storage after passing through drying column 11.

[0031] Preferably, the inlet end of drying column 11 is connected to the first three-way valve 111, which is used for connecting the measured gas and inert gas respectively. The inert gas enters the drying column 11 and the connecting pipeline at the rear end through the first three-way valve 111, realizes the purging function, removes the impurity gas and empties. The inert gas can also be used as a pressurized gas, which is filled into the sample cavity 12 to press the measured gas stored therein into the connecting pipeline at the rear end.

[0032] A first gas mass flow controller 112 can be arranged on the connecting pipeline between the drying column 11 and the sample chamber 12, for regulating the gas flow.

[0033] The outlet end of the sample chamber 12 is connected to an adsorption unit through a first pipeline 121. In the embodiment, the adsorption unit comprises a breakthrough column 13 filled with solid porous adsorption material. The breakthrough column 13 is connected to the first pipeline 121 at its inlet end, and the outlet end of the breakthrough column 13 is connected to an analysis and detection unit through a second pipeline 122.

[0034] The first pipeline 121 can be provided with a pressure detection device, such as a pressure sensor, for detecting the pressure in the first pipeline 121 and the sample chamber 12.

[0035] The adsorption unit further comprises a temperature control device 14 arranged corresponding to the breakthrough column 13 and used for heating the breakthrough column 13. The temperature control device 14 can further comprise a heating jacket wrapped around the breakthrough column 13, and / or a heating element arranged on the breakthrough column 13, etc.

[0036] The analysis and detection unit further comprises a gas detector 15 connected to the outlet end of the breakthrough column 13 through the second pipeline 122. The second pipeline 122 can be connected to an exhaust pipeline or a detection pipeline through a fourth three-way valve 125. The gas detector 15 can be, but is not limited to, a GCW3523 high-purity germanium gamma spectrometer, a HA1310 high-voltage ionization chamber, or a FYFS-400X plastic double scintillator measuring instrument.

[0037] Further, the gas detection system further comprises a working gas source 16 for providing working gas, and a third pipeline 161 connected between the working gas source 16 and the inlet end of the breakthrough column 13, for introducing the working gas into the breakthrough column 13 to carry the desorbed target gas. A second gas mass flow controller 162 can be arranged on the third pipeline 161, for regulating the gas flow.

[0038] Preferably, the first pipeline 121 and the third pipeline 161 are connected to the inlet end of the breakthrough column 13 through a second three-way valve 123, so as to control the connection passage of the inlet end of the breakthrough column 13. The first pipeline 121 can also be connected to a vacuum pump through a third three-way valve 124, for vacuumizing.

[0039] Figure 1 When the gas detection system is used:

[0040] The solid porous adsorption material is pre-activated at a temperature of 100-150°C for 3-5 hours under vacuum.

[0041] The activated solid porous adsorbent material is filled into the breakthrough column 13 (filling amount 1g~10g) and heated to 80℃~150℃. The first three-way valve 111 is adjusted to connect the inert gas to the drying column 11, and the first gas mass flow controller 112 is adjusted to control the purge flow rate at 10mL / min~50mL / min. The inert gas Ar / He is used to purge the drying column 11, the sample chamber 12, and the breakthrough column 13 for two hours to remove impurity gases in the connecting pipeline and to evacuate.

[0042] The third three-way valve 124 is adjusted to open the vacuum pump, and the sample chamber 12 is evacuated. The first three-way valve 111 is adjusted to connect the drying column 11 to the gas to be measured, and the gas flow is controlled by the first gas mass flow controller 112 at 100mL / min~200mL / min. The pressure difference is used to introduce the gas to be measured into the sample chamber 12 to atmospheric pressure (measured by the rear-end pressure sensor of the sample chamber 12), and the gas path is closed.

[0043] The first three-way valve 111 is adjusted to connect the inert gas to the drying column 11, and the first gas mass flow controller 112 is adjusted to control the purge flow rate at 20mL / min~30mL / min. The second three-way valve 123 and the third three-way valve 124 are adjusted to connect the sample chamber 12 and the breakthrough column 13. The gas to be measured in the sample chamber 12 is purged into the breakthrough column 13. After the pressure value of the sample chamber 12 reaches 1.2bar~2bar, the fourth three-way valve 125 is closed, and the pressure is held for 1h~2h.

[0044] The first three-way valve 111 is adjusted to connect the inert gas to the drying column 11, and the first gas mass flow controller 112 is adjusted to control the purge flow rate at 2mL / min~10mL / min. The fourth three-way valve 125 is adjusted to connect the evacuation pipeline or the detection pipeline. The inert gas is used to purge the gas to be measured in the breakthrough column 13 into the detection pipeline to enter the rear-end gas detection device, and the amount of gas to be measured adsorbed on the solid porous adsorbent material is evaluated.

[0045] The gas detector 15 is connected to the vacuum pump for vacuum operation, and the working gas connected to the gas detector 15 is filled into the cavity of the gas detector 15 to atmospheric pressure. The above operation is repeated 3~5 times to ensure that the impurity gas in the gas detector 15 is completely replaced, and finally the gas detector 15 is in a vacuum state. The above completes the cavity cleaning operation of the gas detector 15.

[0046] The temperature control device 14 is turned on, the breakthrough column 13 is heated to 80℃~100℃, the working gas source 16 and the breakthrough column 13 are connected, the breakthrough column 13 and the gas detector 15 are connected, the flow rate of the working gas is controlled at 500mL / min~1L / min, and the working gas carrying the desorbed gas to be measured enters the cavity of the gas detector 15 and is purged to atmospheric pressure in the cavity of the gas detector 15.

[0047] The penetration column 13 and the gas detector 15 are disconnected, and the entire gas detector 15 is in a closed state, at this time, the gas detector 15 is filled with working gas and desorbed measured gas, and signal monitoring is started. The gas detector 15 monitors the signal of the alpha or beta particles released by the radioactive gas decay, and obtains information such as the activity concentration of the radioactive gas through conversion, and then qualitative and quantitative analysis can be achieved.

[0048] As shown in Figure 2 The gas detection system of the second embodiment of the utility model, including drying unit, adsorption unit and analysis detection unit which are connected in turn.

[0049] The drying unit is used for connecting the measured gas and drying the measured gas. The adsorption unit receives the dried measured gas and adsorbs the measured gas through the solid porous adsorption material filled in the adsorption unit. The analysis detection unit is used for analyzing and detecting the measured gas, including detecting the type of radioactive inert gas in the measured gas and detecting the activity concentration.

[0050] In this embodiment, the drying unit includes a drying column 11 and a constant flow pump 17. The inlet end of the drying column 11 is used for connecting the measured gas, and the outlet end of the drying column 11 is connected to the inlet end of the constant flow pump 17 through the connecting pipeline.

[0051] Preferably, the inlet end of the drying column 11 is connected to a first three-way valve 111, which is used for connecting the measured gas and inert gas respectively. The inert gas enters the drying column 11 and the connecting pipeline at the rear end through the first three-way valve 111, realizes the purging function, removes the impurity gas, and empties. The inert gas can also be used as a pressurized gas, which is filled into the sample cavity 12 to press the measured gas stored therein into the connecting pipeline at the rear end.

[0052] A first gas mass flow controller 112 can also be arranged on the connecting pipeline of the drying column 11 and the constant flow pump 17, which is used for regulating the gas flow.

[0053] The outlet end of the constant flow pump 17 is connected to the adsorption unit through a first pipeline 121. In this embodiment, the adsorption unit includes a penetration column 13 filled with solid porous adsorption material. The penetration column 13 is connected to the first pipeline 121 at its inlet end, and the outlet end of the penetration column 13 is connected to the analysis detection unit through a second pipeline 122.

[0054] Unlike the first embodiment, in this embodiment, the outlet end of the penetration column 13 is also connected to the measured gas (such as a tank or a chamber storing the measured gas) through a circulating pipeline 171, so that the measured gas, the drying column 11, the constant flow pump 17 and the penetration column 13 are connected to form a loop. In this way, by circulating the measured gas in the loop, the amount of measured gas adsorbed by the penetration column 13 is ensured or increased.

[0055] The first pipeline 121 can be provided with a pressure detection device, such as a pressure sensor, for detecting the pressure of the first pipeline 121.

[0056] The adsorption unit further comprises a temperature control device 14 arranged corresponding to the penetration column 13 and used for heating the penetration column 13. The temperature control device 14 can further comprise a heating jacket wrapped outside the penetration column 13, and / or a heating element arranged on the penetration column 13, etc.

[0057] The analysis and detection unit further comprises a gas detector 15 connected with the outlet end of the penetration column 13 through a second pipeline 122. The second pipeline 122 can be connected with an exhaust pipeline or a detection pipeline through a fourth three-way valve 125. The gas detector 15 can be selected from, but not limited to, a GCW3523 high-purity germanium gamma spectrometer, a HA1310 high-voltage ionization chamber, or a FYFS-400X plastic double scintillator measuring instrument.

[0058] Further, the gas detection system further comprises a working gas source 16 for providing working gas and a third pipeline 161 connected between the working gas source 16 and the inlet end of the penetration column 13, for introducing the working gas into the penetration column 13 to carry the desorbed to-be-detected gas. The third pipeline 161 can be further provided with a second gas mass flow controller 162 for regulating the gas flow.

[0059] Preferably, the first pipeline 121 and the third pipeline 161 are connected with the inlet end of the penetration column 13 through a second three-way valve 123, so as to control the connection passage of the inlet end of the penetration column 13. The first pipeline 121 can be further connected with a vacuum pump through a third three-way valve 124 for vacuumizing.

[0060] The use of the gas detection system shown in the to-be-detected gas is radon gas. Figure 2 The use of the gas detection system shown in the to-be-detected gas is radon gas.

[0061] Firstly, the gas detector 15 is vacuumized by a vacuum pump connected therewith, and then working gas connected with the gas detector 15 is filled into the gas detector 15 to carry out cleaning operation. The above operation is repeated for 3-5 times to ensure that the impurity gas in the gas detector 15 is completely replaced, and finally the gas detector 15 is in a vacuum state.

[0062] All valves and mass flow controllers are closed, and the permeation column 13 is filled with solid porous adsorbent material. First, the solid porous adsorbent material is activated as follows: The permeation column 13 is heated to 100℃~150℃ using temperature control device 14, inert gas is introduced, and the flow rate of the first gas mass flow controller 112 is controlled at 100mL / min~150 mL / min, allowing the gas to be purged through the permeation column 13 to the branch line. After purging for 1 hour, temperature control device 14 is turned off, and purging continues until the permeation column 13 reaches room temperature, completing the activation process.

[0063] Connect the gas to be tested to the drying column 11 and the constant flow pump 17. Control the flow rate of the constant flow pump 17 to 100 mL / min to 200 mL / min. Open the first three-way valve 111 and adjust the first gas mass flow controller 112 to the cleaning mode. Open the third three-way valve 124, the second three-way valve 123, and the fourth three-way valve 125. Connect the gas to be tested through the circulation pipeline 171. At this time, the penetration column 13 adsorbs the radon gas of the set concentration in the gas to be tested for 1 h to 3 h until the adsorption is completed.

[0064] Then, close the second three-way valve 123 and the fourth three-way valve 125, and heat the penetration column 13 to 100℃~150℃. Evacuate the gas detector 15 to a vacuum, and open the second three-way valve 123 and the fourth three-way valve 125 to connect the working gas source 16 to the penetration column 13 and the gas detector 15. Control the flow rate of the second gas mass flow controller 162 to 500 mL / min~1 L / min. The working gas purges the penetration column 13, carrying the desorbed radon gas into the gas detector 15. After reaching atmospheric pressure, disconnect the connection between the penetration column 13 and the gas detector 15; the gas detector 15 begins signal monitoring.

[0065] like Figure 3 As shown, the gas detection system of the third embodiment of this utility model includes a drying unit, an adsorption unit, and an analysis and detection unit connected in sequence.

[0066] The drying unit is used to receive and dry the gas to be tested. The adsorption unit receives the dried gas and adsorbs it using a solid porous adsorption material packed inside. The analysis and detection unit is used to analyze and detect the gas to be tested, including detecting the type and activity concentration of radioactive inert gases.

[0067] The unit includes a drying column 21; the adsorption unit includes at least one adsorption column packed with solid porous adsorption material; the drying column 21 can be connected to the adsorption column via a first conduit, and the dried analyte gas enters the adsorption column through the first conduit. The analytical detection unit includes a chromatographic column 24 connected to the adsorption column and a gas analysis detector 25 connected to the chromatographic column 24; the adsorption column can be connected to the chromatographic column 24 via a second conduit. The gas analysis detector 25 can be selected from, but is not limited to, an Agilent 8890 gas chromatograph, a gas chromatography-mass spectrometry (Agilent 7890B-5977A) system, or a Shimadzu GCMS-QP2010Plus system, etc.

[0068] Specifically, the inlet of the drying column 21 can be connected via a pipeline to a sample container containing the gas to be tested and an inert gas source (such as a He gas container), while the outlet of the drying column 21 is connected to an adsorption column. The drying column 21 dries the gas to be tested entering it, removing water and carbon dioxide. The gas to be tested exiting the drying column 21 enters the adsorption column for adsorption and concentration, removing impurities and increasing the concentration of the target gas in the gas to be tested.

[0069] exist Figure 2 In the illustrated embodiment, the adsorption unit includes two adsorption columns respectively filled with solid porous adsorption material, serving as the first adsorption column 22 and the second adsorption column 23. The first adsorption column 22 and the second adsorption column 23 are connected in series.

[0070] The chromatographic column 24 separates the gas to be tested after adsorption and concentration treatment, and then sends it to the gas analysis detector 25 to analyze and detect the gas type and active concentration.

[0071] Furthermore, the gas detection system also includes a collection unit connected to the gas analyzer 25 for collecting the gas to be tested after passing through the gas analyzer 25.

[0072] The collection unit includes at least one collection column filled with a solid porous adsorbent material. For example... Figure 2 As shown, taking the case where the target gases in the gas to be tested are Kr and Xe as an example, the corresponding collection columns are Kr collection column 26 and Xe collection column 27.

[0073] Figure 2 When using the gas detection system shown:

[0074] The analysis detection unit is calibrated in advance, and the operation is as follows: a proper amount of Kr and Xe standard gas is injected through the standard column 28 to calibrate the gas analysis detector 25 to obtain the target spectrum of the chromatographic workstation when the Kr / Xe output. The concentration of Kr and Xe in the standard gas is equivalent to that in the gas to be measured. After the standard gas is injected into the standard column 28, the obtained peak spectrum after chromatographic separation and gas analysis detector 25 detection is recorded by the chromatographic workstation and used as the peak timing reference in the formal experiment of the gas to be measured.

[0075] Valve operation: open the standard column sampling valve, control the six-way valve, four-way 1, and four-way 2 as Figure 2 , and input the sample gas into the standard column. Switch the four-way 1 state and the four-way 2 state, open the gas analysis detector, and inject standard He gas. The He carrier carries the sample gas in the standard column 28, passes through the chromatographic column 24 in the four-way 2, enters the gas analysis detector 25, and the separation spectrum of the standard gas is observed and recorded from the side of the chromatographic workstation.

[0076] Pre-absorption of the gas to be measured before detection:

[0077] 3L of the gas to be measured is pushed into the entire system by an external carrier gas He source, the carrier gas flow is controlled, and the 3L of the gas to be measured is continuously blown into the system to enter the drying link.

[0078] The gas to be measured is pushed into the drying column 21 to remove a large amount of water and carbon dioxide in the gas to be measured, and the target gas Kr, Xe, and the impurities N2 and O2 with high content flow to the adsorption unit for two times of adsorption and concentration.

[0079] After drying, the gas to be measured is concentrated twice to make the nitrogen and oxygen impurities in the gas to be measured be carried and discharged by the helium flow, and the Kr and Xe gas with high purity is obtained.

[0080] The specific process is as follows: after all the gas to be measured is dried, it enters the first adsorption column 22, and the Kr and Xe target gas is adsorbed by the solid porous adsorption material (such as MOFs formed material) in the column. In the competitive adsorption environment, the adsorption capacity of Kr and Xe in the MOFs formed material is stronger than that of other impurity gases, so a large amount of unadsorbed impurity gas passes through the three-way valve connected to the first adsorption column 22 and is emptied under the flow washing of the He carrier gas.

[0081] Subsequently, the first adsorption column 22 is heated (the activation temperature is determined by the material properties), the adsorbed Kr and Xe gas in the column is desorbed, and the first adsorption column 22 is flow-washed by the external He carrier gas flow, so that the desorbed Kr and Xe gas is transferred into the second adsorption column 23, and the adsorption process of the first adsorption column 22 is repeated. Part of the nitrogen and oxygen impurities remaining in the first adsorption column 22 are further carried and emptied. Kr and Xe are further concentrated.

[0082] The second adsorption column 23 is heated (activation temperature determined by material properties) to desorb the Kr and Xe gas adsorbed in the column, which is pushed into the chromatographic separation operation by the carrier gas He.

[0083] Chromatographic separation and gas analysis detection:

[0084] The second adsorption column 23 is washed by an external He gas source, and the Kr and Xe adsorbed in the second adsorption column 23 are desorbed and enter the chromatographic column 24 by heating and desorption of the second adsorption column 23. The Kr, Xe and a small amount of impurity gas (mainly N2) carried by the carrier gas He are separated by the chromatographic column, and then flow out of the chromatographic column 24 in sequence and flow through the gas analysis detector 25.

[0085] By monitoring and comparing the out-of-peak conditions of the calibrated gas analysis detector 25, the gas type (Kr or Xe) and the sample concentration are determined, and the Kr and Xe gas are collected into the corresponding Kr collection column 26 and Xe collection column 27 (filled with MOFs shaped material) by the control collection unit.

[0086] When the Kr and Xe gas are collected by the corresponding collection column, the Kr collection column 26 and the Xe collection column 27 are heated (activation temperature determined by material properties), and the desorbed Kr and Xe are pushed into the sample bottle by the external He gas source, thereby completing the separate collection of Kr and Xe.

[0087] System activation and regeneration:

[0088] After the completion of the "adsorption-separation-collection" process, the system is activated and regenerated. The impurity gas in the activated system is pumped out, and the adsorption capacity of each column is restored.

[0089] As shown in Figure 4 The gas detection system of the fourth embodiment of the utility model, including drying unit, adsorption unit and analysis detection unit which connect in turn.

[0090] The drying unit is used for connecting the to-be-measured gas and drying the to-be-measured gas. The adsorption unit receives the dried to-be-measured gas and adsorbs the to-be-measured gas by the solid porous adsorption material filled in the adsorption unit. The analysis detection unit is used for analyzing and detecting the to-be-measured gas, including detecting the type of radioactive inert gas in the to-be-measured gas and detecting the activity concentration.

[0091] The system comprises: a drying unit including at least one drying column; an adsorption unit including at least one adsorption column (gas adsorption column) filled with solid porous adsorption material; and an analysis and detection unit including a gas analyzer 35 for receiving the analyte gas not adsorbed by the adsorption unit, detecting whether the treated analyte gas meets emission standards, and otherwise returning it to the front end of the system for secondary treatment. The gas analyzer 35 is connected to the front end of the iodine adsorption column via a branch, which enables the return flow function.

[0092] Specifically, the inlet of the drying column can be connected to the gas to be tested and an inert gas via pipelines and a three-way valve. A gas mass flow controller is also installed on the pipeline to regulate the gas flow rate. The outlet of the drying column is connected to an adsorption column. The drying column dries the gas to be tested entering it, removing water and carbon dioxide. The gas to be tested exiting the drying column then enters the adsorption column for adsorption treatment.

[0093] exist Figure 3 In the illustrated embodiment, the drying unit includes two drying columns connected in series, serving as the first drying column 31 and the second drying column 32, respectively. The first drying column 31 and the second drying column 32 are respectively filled with 4Å molecular sieve / CaCl2 / caustic soda flakes, etc., for fully adsorbing and removing impurity gases such as N2, O2, CO2, and water vapor. The adsorption unit includes two adsorption columns respectively filled with solid porous adsorbent material and connected in series, serving as the first adsorption column 33 and the second adsorption column 34.

[0094] Furthermore, taking the test gas as an example simulating the actual gaseous effluent from a nuclear power plant, in addition to the target gases Kr and Xe, it may also contain I-containing compounds, NOx, N2, O2, CO2, and water vapor. Different adsorption materials with varying properties can be used to achieve stepwise separation of different gases. To meet the requirements of better material adsorption at low temperatures and to remove iodine gas and nitrogen oxide impurities, the gas detection system in this embodiment is more advanced than... Figure 3 The embodiment shown includes an added purification unit.

[0095] The purification unit includes an iodine adsorption column 36 for adsorbing and removing impurities from the test gas, and a wet scrubbing device 37 (using denitrification agents such as ammonia or urea) for converting nitrogen oxides in the test gas into HNO3. The iodine adsorption column 36 is connected to the inlet end of the drying column, and the wet scrubbing device 37 is connected between the inlet ends of the iodine adsorption column 36 and the drying column. The iodine adsorption column 36 is filled with functionalized silica aerogel and other materials to fully adsorb I-containing compounds.

[0096] The target gases are Kr and Xe, and the first adsorption column 33 and the second adsorption column 34 are Kr adsorption columns and Xe adsorption columns, respectively.

[0097] The drying unit also comprises a first temperature control device 39 that can be controlled at low or high temperature, which is used to heat or cool the drying column (the first drying column 31 and the second drying column 32). The adsorption unit also comprises a second temperature control device 30 that can be controlled at low or high temperature, which is used to heat or cool the adsorption column (the first adsorption column 33 and the second adsorption column 34).

[0098] The gas analysis detector 35 can be, but is not limited to, Agilent 8890 gas chromatograph, gas chromatograph-mass spectrometer (such as Agilent 7890B-5977A) or Shimadzu GCMS-QP2010Plus gas chromatograph-mass spectrometer, etc.

[0099] Figure 4 When the gas detection system shown is used:

[0100] First, the first temperature control device 39 and the second temperature control device 30 are turned on to heat to 100℃-150℃, and the drying column (the first drying column 31 and the second drying column 32) and the adsorption column (the first adsorption column 33 and the second adsorption column 34) are heated. Inert gas is introduced, and the flow rate is controlled at 100mL / min-200mL / min. The inert gas purges the entire system circuit for 1-2 hours, and the back end is emptied.

[0101] Gas purification:

[0102] The main purpose is to study the adsorption characteristics of Xe and Kr on solid porous adsorption materials. The corresponding solid porous adsorption materials (such as MOFs materials) are filled in the Xe adsorption column and the Kr adsorption column, respectively. Through temperature control and other operations, effective adsorption and purification of Kr and Xe gas are achieved. The back end is connected to the gas analysis detector 35, inert gas is used as the carrier gas, and the composition of the gas to be detected after adsorption treatment is detected to determine whether it meets the emission standard. If not, the gas to be detected after the first treatment is subjected to secondary purification treatment until it meets the standard and can be discharged.

[0103] Valve control: control the cold gas to be at a low temperature of -80--150℃ in the Xe and Kr adsorption columns. By adjusting the valve, the drying column is connected to the Kr adsorption column and the Xe adsorption column. At this time, the remaining gas after impurity removal first passes through the Xe adsorption column to complete the retention of Xe. Then the remaining Kr gas passes through the Kr adsorption column to complete the retention of Kr gas. Control the valve to make the Kr adsorption column communicate with the gas analysis detector 35. The inert gas carrier may not be adsorbed into the gas analysis detector 35. The treated gas is detected to determine whether it meets the emission standard. If not, secondary treatment (repeat the above operation) is performed.

[0104] Activation system:

[0105] After the end of the operation of the "adsorption-separation-purification" process, the system is activated and regenerated. After activation, the impurity gas in the system is pumped out, and the drying column and the adsorption column restore the secondary adsorption capacity.

[0106] In the above embodiment, the solid porous adsorbent material used can be a shaped CZIF-8@950-S material after carbonization of ZIF-8 at 950℃. The specific preparation method is as follows: take 20 g of Zn(NO3)2·6H2O, add 1000 mL of anhydrous methanol and stir until the solid is completely dissolved. Add 26 g of 2-methylimidazole at room temperature, stir for 2 min to obtain a transparent solution. After a period of time, white crystals are precipitated in the solution, and after 16 h, the white solid is filtered out and placed in a vacuum drying oven at 80℃ for 24 h to obtain ZIF-8 powder. The prepared ZIF-8 powder is ground and loaded into a ceramic crucible for carbonization treatment under Ar atmosphere. The heating process of the tube furnace is as follows: heat the sample to 950℃ at a heating rate of 5℃ / min. After holding for 2 h, the sample is naturally cooled with the furnace, and the obtained sample is marked as CZIF-8@950. According to the mass ratio of CZIF-8@950 powder:methyl cellulose=95:5, take 1.9 g of CZIF-8@950 powder and 0.1 g of methyl cellulose, mix them evenly in a beaker, add deionized water drop by drop and continuously stir until a paste is formed, then take it out and knead repeatedly to make the viscosity uniform; take a small amount of sample and knead it into 1~2 mm small balls, dry the small balls in a 70℃ oven overnight after preparation; break the small balls in a mortar, sieve and retain the 60 mesh~40 mesh diameter sized shaped materials, and the shaped material sample is marked as CZIF-8@950-S.

[0107] In 10 6 After Gy irradiation, ZIF-8, CZIF-8@950 and CZIF-8@950-S have good appearance and good irradiation stability.

[0108] Understandably, in the utility model, the solid porous adsorbent material can be selected according to the specific target gas (radioactive noble gas krypton, xenon or radon, etc.).

[0109] The above is only an embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structure or equivalent process conversion using the contents of the utility model specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the utility model.

Claims

1. A gas detection system, characterized in that, It includes a drying unit for receiving and drying the gas to be tested, an adsorption unit filled with solid porous adsorption material for adsorption treatment of the gas to be tested, and an analytical detection unit for detecting radioactive inert gases in the gas to be tested; The drying unit, adsorption unit, and analysis and detection unit are connected in sequence. The drying unit includes a drying column and a sample chamber; the adsorption unit includes a permeation column filled with the solid porous adsorption material; the inlet end of the drying column is used to receive the gas to be tested, the outlet end of the drying column is connected to the sample chamber, and the sample chamber is connected to the inlet end of the permeation column through a first conduit; the analysis and detection unit includes a gas detector, and the gas detector is connected to the outlet end of the permeation column through a second conduit; or, The drying unit includes a drying column and a constant flow pump; the adsorption unit includes a permeation column filled with the solid porous adsorption material; the inlet end of the drying column is used to receive the gas to be tested, and the outlet end of the drying column is connected to the constant flow pump, which is connected to the inlet end of the permeation column through a first pipeline; the analysis and detection unit includes a gas detector, which is connected to the outlet end of the permeation column through a second pipeline; the outlet end of the permeation column is also connected to the gas to be tested through a circulation pipeline, so that the gas to be tested, the drying column, the constant flow pump, and the permeation column are connected to form a loop; The gas detection system also includes a working gas source and a third pipeline that provides working gas. The third pipeline is connected between the working gas source and the inlet end of the penetration column. The working gas is introduced into the penetration column so that the gas to be tested desorbed from the carrier enters the gas detector for gas detection.

2. The gas detection system according to claim 1, characterized in that, The inlet end of the drying column is connected to a first three-way valve, which is used to connect the gas to be tested and the inert gas, respectively.

3. The gas detection system according to claim 1, characterized in that, The adsorption unit also includes a temperature control device, which is configured to heat the penetration column.

4. The gas detection system according to claim 1, characterized in that, The drying unit includes at least one drying column; the adsorption unit includes at least one adsorption column filled with the solid porous adsorption material.

5. The gas detection system according to claim 4, characterized in that, The analytical detection unit includes a chromatographic column connected to the adsorption column and a gas analysis detector connected to the chromatographic column; or, the analytical detection unit includes a gas analysis detector connected to the adsorption column.

6. The gas detection system according to claim 5, characterized in that, The gas detection system also includes a collection unit connected to the gas analysis detector for collecting the gas to be tested; The collection unit includes at least one collection column filled with solid porous adsorbent material.

7. The gas detection system according to any one of claims 4-5, characterized in that, The gas detection system also includes a purification unit; The purification unit includes an iodine adsorption column for adsorbing and removing impurities from the gas to be tested, and a wet scrubbing device for converting nitrogen oxides in the gas to be tested into HNO3. The iodine adsorption column is connected to the inlet end of the drying column, and the wet washing device is connected between the inlet ends of the iodine adsorption column and the drying column.

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