Device and method for monitoring carbon-14 in gaseous effluent

Abstract

The invention provides a device and a method for monitoring carbon-14 in gaseous effluent, and particularly relates to the technical field of radionuclide detection. The monitoring device comprises an oxidative combustion assembly, a gas treatment assembly, a drying and grinding assembly, an incineration collection assembly and a spectrograph, and the oxidative combustion assembly is used for carrying out incineration treatment on gaseous effluent so as to convert the gaseous effluent into gas containing carbon dioxide; the gas treatment assembly is communicated with an exhaust pipe of the oxidative combustion assembly, the gas treatment assembly comprises alkali liquor, and the alkali liquor absorbs carbon dioxide and reacts with injected sodium chloride to form calcium carbonate precipitates; the drying and grinding assembly is used for drying and grinding the calcium carbonate precipitate and converting the calcium carbonate precipitate into calcium carbonate powder; the incineration collection assembly pyrolyzes calcium carbonate powder into carbon dioxide gas and collects the carbon dioxide gas; the spectrograph is communicated with the incineration collection assembly and is used for measuring the carbon-14 concentration of the carbon dioxide gas. By adopting the monitoring device disclosed by the invention, the monitoring precision of carbon-14 can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radionuclide detection, and in particular to a device and method for monitoring carbon-14 in gaseous effluent. Background Art

[0002] Carbon-14 in the gaseous outflow pipe of a nuclear power plant ( 14 C) with carbon dioxide ( 14 CO2), with a small amount of organic carbon compounds, such as 14 C of carbon monoxide ( 14 CO) and methane ( 14 CH4), 14 C can easily enter the biosphere through the ecological cycle and then enter the human body, causing radiation damage. 14 C measurement is done by sampling. A sampler is used to collect enough sample gas, which is dissolved in a sodium hydroxide solution and then precipitated or converted into carbon dioxide to make a sample source, which is then placed in a liquid scintillation spectrometer for measurement.

[0003] However, the gaseous outflow pipes of nuclear power plants are in the form of carbon monoxide and methane. 14 C. Since the two will not react with sodium hydroxide solution, this will easily lead to inaccurate monitoring results. In addition, conventional carbon dioxide will not react with the sodium hydroxide solution when poured into the sodium hydroxide solution. Some carbon dioxide will also separate from the sodium hydroxide solution in the form of gas, which will undoubtedly increase 14 In addition, liquid scintillation spectrometers require the use of scintillation liquid with certain toxicity and reactivity as a detection substance, and the resulting samples need to be treated as hazardous waste, which is environmentally unfriendly.

[0004] In view of this, a device and method for monitoring carbon-14 in gaseous effluent are proposed. Summary of the Invention

[0005] The present invention provides a monitoring device and method for carbon-14 in gaseous effluent to solve the problem of existing gaseous effluent pipe 14 C measurement has a technical problem of large errors in monitoring results.

[0006] The present invention provides a device for monitoring carbon-14 in gaseous effluent, comprising: an oxidizing combustion component, a gas processing component, a drying and grinding component, an incineration collection component, and a spectrometer. The oxidizing combustion component is used to incinerate the gaseous effluent to convert the gaseous effluent into a gas containing carbon dioxide. The gas processing component is connected to the exhaust pipe of the oxidizing combustion component. The gas processing component includes an alkaline solution, which absorbs the carbon dioxide and reacts with injected sodium chloride to form a calcium carbonate precipitate. The drying and grinding component is used to dry and grind the calcium carbonate precipitate to convert the calcium carbonate precipitate into calcium carbonate powder. The incineration collection component pyrolyzes the calcium carbonate powder to convert it into carbon dioxide gas and collects it. The spectrometer is connected to the incineration collection component and is used to measure the carbon-14 concentration in the carbon dioxide gas.

[0007] In one embodiment of the present invention, the gas processing assembly includes: a fixed cylinder, a lifting platform, an alkali liquid cup, an air inlet pipe, and an air outlet pipe, wherein the lifting platform is arranged inside the fixed cylinder, the alkali liquid cup is used to hold the alkali liquid and is arranged on the top of the lifting platform, the air inlet pipe and the air outlet pipe are respectively arranged on both sides of the top of the fixed cylinder, and one end of the air inlet pipe is connected to the exhaust pipe, and the other end is connected to the alkali liquid cup, and one end of the air outlet pipe is connected to the exhaust pipe, and the other end is connected to the alkali liquid cup;

[0008] The air inlet pipe is provided with a first switch valve, a first flow sensor and a first one-way valve in sequence, and the air outlet pipe is provided with a second switch valve, a second flow sensor and a second one-way valve in sequence.

[0009] In one embodiment of the present invention, the gas processing assembly also includes a stirring device, which includes a drive motor, a rotating shaft, a stirring frame and a bracket. The drive motor is installed on the fixed cylinder, and the rotating shaft is arranged inside the fixed cylinder. One end of the rotating shaft is fixedly connected to the output end of the drive motor, and the other end extends along the axial direction of the fixed cylinder. The stirring frame is arranged on the rotating shaft, and the bracket is fixed to the bottom of the rotating shaft.

[0010] In one embodiment of the present invention, a diverter plate is further provided on the rotating shaft, and the diverter plate is arranged between the stirring frame and the bracket. The bottom end of the air inlet pipe passes through the diverter plate and extends to the bottom of the diverter plate. A plurality of diverter holes are provided on the diverter plate.

[0011] In one embodiment of the present invention, the lifting platform includes a tray and a screw rod, one end of the screw rod is rotatably connected to the tray, the other end of the screw rod passes through the bottom of the fixed tube and is threadedly connected to the fixed tube, and a knob is fixedly installed on one end of the screw rod passing through the bottom of the fixed tube.

[0012] In one embodiment of the present invention, the tray is provided with a receiving groove for the alkali liquid cup, the bottom of the alkali liquid cup is provided with a plurality of positioning blocks, and the receiving groove is provided with a plurality of positioning grooves cooperating with the positioning blocks; and / or, the top wall of the inner cavity of the fixing cylinder is provided with a sealing ring, and the sealing ring cooperates with the alkali liquid cup to seal.

[0013] In one embodiment of the present invention, a feeding hopper communicating with the interior of the fixed cylinder is further provided on the top of the fixed cylinder, and a sealing cap is connected to the feeding hopper; and a transparent observation door is hinged on the fixed cylinder.

[0014] In one embodiment of the present invention, the incineration collection component is connected to the air inlet end of the spectrometer through a three-way pipe, the air inlet end of the three-way pipe is connected to a gas guide tube, the end of the gas guide tube away from the three-way pipe is connected to the air outlet end of the incineration collection component through an air pump, and the air inlet end of the spectrometer is provided with a first solenoid valve; the other end of the three-way pipe is connected to an exhaust pipe, and the exhaust pipe is provided with a second solenoid valve.

[0015] In one embodiment of the present invention, a condenser is provided inside the gas flow guide tube, and the two ends of the condenser are respectively connected to a cold liquid inlet pipe and a cold liquid outlet pipe. The cold liquid inlet pipe and the cold liquid outlet pipe both pass through the gas flow guide tube and extend to the outside of the gas flow guide tube.

[0016] The present invention also provides a method for monitoring carbon-14 in gaseous effluent, wherein the method adopts any of the above-mentioned monitoring devices for monitoring, and the method comprises the following steps:

[0017] The gaseous effluent is mixed with oxygen and nitrogen, and then transported to the oxidation combustion component to be heated to 700-1000°C, and fully burned to generate gas containing carbon dioxide, which is discharged through the exhaust pipe;

[0018] introducing the gas containing carbon dioxide in the exhaust pipe into a gas treatment component to react with alkali solution, and injecting calcium chloride into the gas treatment component to obtain calcium carbonate precipitate;

[0019] placing the calcium carbonate precipitate in a drying and grinding assembly for drying and grinding to obtain calcium carbonate powder;

[0020] The calcium carbonate powder is placed in an incineration and collection assembly for incineration and pyrolysis to generate carbon dioxide gas, which is then transported to a spectrometer;

[0021] The concentration of carbon-14 in carbon dioxide is measured using a spectrometer.

[0022] Beneficial effects of the present invention: The present invention proposes a monitoring device for carbon-14 in gaseous effluents, which burns the gaseous effluents through an oxidative combustion component to generate carbon dioxide. 14 The comprehensive collection of C, and then the measurement and calculation of the absolute difference between the inlet and outlet flow rates, to achieve effective calculation of carbon dioxide absorption, and thus to achieve accurate collection of carbon dioxide, for 14 The concentration of C is accurately measured to provide effective support, and then the absorption of carbon dioxide is extracted through the conversion of calcium carbonate. While convenient for storage, the output of carbon dioxide is achieved by pyrolysis of calcium carbonate, so that the spectrometer can be used for 14 The monitoring of C, which achieves quantitative carbon dioxide acquisition through chemical conversion, not only has the advantage of high monitoring accuracy, but also avoids the environmental unfriendly problems brought about by traditional monitoring methods.

[0023] The coordinated setting of the lifting platform and the fixed cylinder enables the convenient placement and removal of the alkali solution cup, provides convenient conditions for the multiple acquisition of calcium carbonate precipitates, improves the acquisition efficiency of calcium carbonate precipitates, and provides a reference for the treatment of gaseous effluents in nuclear power plants. 14 C monitoring provides convenient conditions for obtaining sampling mean values. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be derived from these drawings without inventive effort.

[0025] In the attached figure:

[0026] Figure 1 A schematic diagram of the flow of carbon-14 in gaseous effluent in a monitoring device according to one embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the connection between the gas processing assembly and the exhaust pipe of the oxidation combustion assembly provided in one embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the internal structure of a gas processing assembly provided in one embodiment of the present invention;

[0029] Figure 4 A schematic diagram of a partial structure of a gas processing assembly provided in one embodiment of the present invention;

[0030] Figure 5 A schematic diagram of a partial structure of a gas processing assembly provided by one embodiment of the present invention from another angle;

[0031] Figure 6 A schematic diagram of the coordination structure of the alkali solution cup and the lifting platform in the gas treatment assembly provided in one embodiment of the present invention;

[0032] Figure 7 Schematic diagram of the connection relationship between the incineration collection component and the spectrometer in one embodiment of the present invention;

[0033] Figure 8 Flowchart of a method for monitoring carbon-14 in gaseous effluent according to one embodiment of the present invention.

[0034] The reference numerals are as follows:

[0035] 1. Oxidation combustion assembly; 101. Exhaust pipe; 2. Gas treatment assembly; 201. Fixing cylinder; 202. Lifting platform; 2021. Tray; 2022. Screw rod; 2023. Knob; 2024. Positioning groove; 2025. Sealing ring; 203. Alkali solution cup; 2031. Positioning block; 204. Inlet pipe; 2041. First switch valve; 2042. First flow sensor; 2043. First check valve; 205. Exhaust pipe; 2051. Second switch valve; 2052. Second flow sensor; 2053. Second check valve; 2 06. Drive motor; 207. Rotating shaft; 208. Stirring frame; 209. Bracket; 2010. Positioning nut; 2011. Diverter plate; 2012. Diverter hole; 2013. Adding hopper; 2014. Sealing cap; 2015. Transparent observation door; 3. Drying and grinding assembly; 4. Incineration collection assembly; 401. T-tube; 402. Gas guide tube; 403. Air pump; 404. First solenoid valve; 405. Exhaust pipe; 406. Second solenoid valve; 407. Condenser; 408. Cold liquid inlet pipe; 409. Cold liquid outlet pipe; 5. Spectrometer. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments. The details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. The following embodiments and features therein may be combined with one another without conflict.

[0037] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The drawings only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0038] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0039] See also Figure 1 The first aspect of the present invention provides a monitoring device for carbon-14 in gaseous effluent, the monitoring device comprising an oxidation combustion component 1, a gas processing component 2, a drying and grinding component 3, an incineration collection component 4 and a spectrometer 5, wherein the oxidation combustion component 1 can detect different forms of carbon-14 in the gaseous effluent. 14 C( 14 CO, 14 CH4, etc.) are all converted into 14 CO2, since the gaseous effluent contains more than 14 C is a radioactive element, and the gaseous effluent after being treated by the oxidation combustion component 1 also contains non 14 CO2 components cannot be directly detected. Therefore, the gas processing component 2 is required to purify the oxidized gas to exclude non- 14 The influence of C element. The gas processing component 2 will oxidize the gas in the combustion component 1. 14 CO2 is converted into calcium carbonate precipitate, and the drying and grinding component 3 dries and grinds the calcium carbonate precipitate to form small particles of calcium carbonate powder. The incineration collection component 4 pyrolyzes the calcium carbonate powder to form pure 14 CO2, spectrometer 5 is used to detect 14 CO2 14 The concentration of C.

[0040] See also Figure 1 and Figure 2 Specifically, the oxidation combustion assembly 1 includes a tubular oxidation furnace and an exhaust pipe 101. The exhaust pipe 101 is connected to the exhaust end of the tubular oxidation furnace. The gaseous effluent discharged from the operation of nuclear facilities such as nuclear power plants can be calcined in the tubular oxidation furnace to oxidize organic carbon compounds into carbon dioxide, enter the exhaust pipe 101, and enter the next stage through the exhaust pipe 101, so as to avoid the carbon monoxide and methane in the gaseous effluent. 14 The gaseous effluent can be introduced into the tubular oxidation furnace through the air inlet pipe. Furthermore, the gaseous effluent can be mixed with oxygen and nitrogen before entering the tubular oxidation furnace. Oxygen acts as an oxidant to remove the gaseous effluent. 14 Compounds of C (such as 14 CH4, 14 CO) is completely oxidized to the target product 14CO2 and maintain a high temperature reaction environment. Nitrogen can be used as a carrier gas and diluent to transport the mixed gas while diluting the combustible mixture to a safe concentration to prevent explosion.

[0041] See also Figure 2 The gas processing component 2 is used as a carbon dioxide quantitative sampling device, which absorbs carbon dioxide gas through alkali solution and then injects saturated calcium chloride liquid to 14 C of carbon dioxide gas is converted into calcium carbonate precipitate.

[0042] See also Figures 2 to 4 In one embodiment, the gas processing assembly 2 includes a fixed cylinder 201, a lifting platform 202, a lye cup 203, an air inlet pipe 204, and an air outlet pipe 205. The fixed cylinder 201 can be a hollow structure of any shape. For example, the fixed cylinder 201 is cylindrical. The lifting platform 202 is disposed within the fixed cylinder 201 and can be raised and lowered along the height direction of the fixed cylinder 201. The lye cup 203 is disposed on top of the lifting platform 202 and can be adjusted in height as the lifting platform 202 is raised and lowered. The lye cup 203 contains lye, such as sodium hydroxide solution. The lifting platform 202 can be used to seal and easily replace the lye cup 203. The air inlet pipe 204 and the air outlet pipe 205 are respectively arranged on both sides of the top of the fixed cylinder 201, and one end of the air inlet pipe 204 is connected to the exhaust pipe 101, and the other end passes through the top of the fixed cylinder 201 and enters the alkali liquid cup 203 to introduce the carbon dioxide gas in the exhaust pipe 101 into the alkali liquid cup 203 to be absorbed by the alkali liquid. One end of the air outlet pipe 205 is connected to the exhaust pipe 101, and the other end is connected to the alkali liquid cup 203.

[0043] See also Figure 5 Furthermore, to effectively determine the amount of carbon dioxide absorbed, the inlet pipe 204 is sequentially provided with a first on-off valve 2041, a first flow sensor 2042, and a first one-way valve 2043. The first on-off valve 2041 controls the flow of gas from the exhaust pipe 101 into the alkali liquid cup 203. The first flow sensor 2042 measures the amount of gas entering the alkali liquid cup 203. The first one-way valve 2043 controls the unidirectional flow of gas from the exhaust pipe 101 into the alkali liquid cup 203. The outlet pipe 205 is sequentially provided with a second on-off valve 2051, a second flow sensor 2052, and a second one-way valve 2053. The second on-off valve 2051 controls the flow of gas not absorbed by the alkali liquid into the exhaust pipe 101 through the outlet pipe 205. The second flow sensor 2052 measures the amount of gas exiting the alkali liquid cup 203. The second one-way valve 2053 controls the unidirectional flow of gas from the alkali liquid cup 203 out of the exhaust pipe 101. During use, the amount of carbon dioxide gas absorbed by the alkali solution can be obtained by measuring the difference in volume flow of the gas passing through the air inlet pipe 204 and the air outlet pipe 205 .

[0044] See also Figure 3 and Figure 6 , the lifting platform 202 can adopt any mechanism that can achieve lifting. In one embodiment, the lifting platform 202 includes a tray 2021 and a screw rod 2022, one end of the screw rod 2022 is rotatably connected to the bottom of the tray 2021, illustratively, through a bearing rotation connection, the other end of the screw rod 2022 extends along the axial direction of the fixed cylinder 201 to penetrate the bottom of the fixed cylinder 201, and is threadedly connected to the fixed cylinder 201, and a knob 2023 is fixedly installed at the bottom of the screw rod 2022. When in use, the tray 2021 can be lifted and lowered by rotating the knob 2023 forward and backward, providing convenient support for the sealing and replacement of the alkali liquid cup 203. Furthermore, a receiving groove for the alkali liquid cup 203 is provided on the top of the tray 2021, and the size of the receiving groove matches the bottom shape of the alkali liquid cup 203. To prevent the lye cup 203 from shaking, several positioning blocks 2031 are circumferentially spaced along its bottom. The receiving tank is provided with several positioning grooves 2024 that cooperate with the positioning blocks 2031. During installation, the bottom of the lye cup 203 fits into the receiving tank, where it is secured by the positioning blocks 2031 and the positioning grooves 2024. Furthermore, a sealing ring 2025 is fixedly mounted on the top wall of the inner cavity of the fixing cylinder 201. During use, the knob 2023 rotates the screw 2022, which raises the tray 2021 containing the lye cup 203 until the top of the lye cup 203 contacts the sealing ring 2025, achieving a seal.

[0045] See also Figure 4 and Figure 5Furthermore, in order to increase the absorption of carbon dioxide by the sodium hydroxide solution, the gas treatment component 2 also includes a stirring device, which can be extended into the alkali solution cup 203 to stir the alkali solution and accelerate the absorption of carbon dioxide gas by the alkali solution. In one embodiment, the stirring device includes a drive motor 206, a rotating shaft 207, a stirring frame 208 and a bracket 209, wherein the drive motor 206 is fixedly installed on the top of the fixed cylinder 201, and the output end of the drive motor 206 passes through the top of the fixed cylinder 201, and the rotating shaft 207 is arranged inside the fixed cylinder 201, one end of the rotating shaft 207 is fixedly connected to the output end of the drive motor 206, and the other end extends along the axial direction of the fixed cylinder 201, and the extension length of the rotating shaft 207 is adapted to the height of the alkali liquid cup 203. When the alkali liquid cup 203 rises to the top of the fixed cylinder 201 and contacts the sealing ring 2025, the rotating shaft 207 extends into the alkali liquid cup 203, and the bottom of the rotating shaft 207 is close to but not in contact with the bottom of the alkali liquid cup 203, so as to prevent the rotating shaft 207 from causing wear to the alkali liquid cup 203 when it rotates. A stirring frame 208 is mounted on the rotating shaft 207 and rotates synchronously with the rotating shaft 207. The stirring frame 208 includes a plurality of stirring blades spaced circumferentially along the rotating shaft 207. As the rotating shaft 207 rotates, the stirring blades agitate the lye in the lye cup 203, accelerating the lye's absorption of carbon dioxide. A bracket 209 is mounted on the bottom of the rotating shaft 207. For example, the bracket 209 is engaged by a flat key sleeve and secured by a positioning nut 2010.

[0046] Furthermore, a diverter plate 2011 is sleeved on the rotating shaft 207, and the diverter plate 2011 is arranged between the bracket 209 and the stirring frame 208. A plurality of diverter holes 2012 are provided on the diverter plate 2011. The bottom end of the air inlet pipe 204 passes through the diverter plate 2011 and extends to the bottom of the diverter plate 2011. The carbon dioxide gas generated in the exhaust pipe 101 is led to the bottom of the diverter plate 2011 by the air inlet pipe 204 and enters the alkali solution through the plurality of diverter holes 2012 on the diverter plate 2011. The cooperation between the diverter plate 2011 and the diverter holes 2012 can reduce the bubbles generated by the injection of carbon dioxide into the sodium hydroxide solution and increase the absorption of carbon dioxide by the sodium hydroxide solution in a stirring manner.

[0047] See also Figure 4 To facilitate the formation of precipitates, a hopper 2013 is located on top of the fixed cylinder 201. This hopper 2013 communicates with the interior of the fixed cylinder 201 and allows saturated calcium chloride to be injected into the lye cup 203, generating calcium carbonate precipitates. A sealing cap 214 is provided on the hopper 2013 to seal it and prevent impurities from entering the lye cup 203 and potentially affecting the monitoring system. The connection between the sealing cap 2014 and the hopper 2013 is not limited and can be threaded or hinged.

[0048] See also Figure 3 The fixed cylinder 201 is also provided with a transparent observation door 2015. For example, an arc-shaped opening is provided on the side wall of the fixed cylinder 201, and the transparent observation door 2015 is hinged to the arc-shaped opening. The interior of the fixed cylinder 201 can be observed through the transparent observation door 2015. In addition, the transparent observation door 2015 can be opened to remove the alkali solution cup 203 or to add or replace the alkali solution in the alkali solution cup 203.

[0049] See also Figure 1 The drying and grinding assembly 3 is used to dry, remove water, and grind the calcium carbonate precipitate to obtain calcium carbonate powder. In one embodiment, the drying and grinding assembly 3 includes an oven and a grinder. The calcium carbonate precipitate is dried in the oven to a constant weight, and then the dried calcium carbonate is ground into a uniform calcium carbonate powder by the grinder. The particle size of the calcium carbonate powder is, for example, less than or equal to 0.1 mm.

[0050] See also Figure 1 and Figure 7 The incineration and collection assembly 4 is used to incinerate calcium carbonate powder to obtain high-purity carbon dioxide gas. The incineration and collection assembly 4 includes a heating furnace and a gas flow tube 402. The heating furnace can be any furnace capable of producing high-temperature pyrolysis of calcium carbonate, such as an electric furnace, a tubular furnace, a muffle furnace, etc. The gas flow tube 402 is connected to the exhaust port of the heating furnace via an air pump 403. The gas flow tube 402 can be made of stainless steel. The air pump can be, for example, a diaphragm pump. The carbon dioxide gas generated by the pyrolysis of calcium carbonate powder in the heating furnace can enter the gas flow tube 402 from the exhaust port via the air pump 403. Furthermore, a condenser 407 is provided inside the gas flow tube 402. The two ends of the condenser 407 are connected to a cold liquid inlet pipe 408 and a cold liquid outlet pipe 409, respectively. The cold liquid inlet pipe 408 and the cold liquid outlet pipe 409 both pass through the gas flow tube 402 and extend to the outside of the gas flow tube 402. The cold liquid inlet pipe 408 and the cold liquid outlet pipe 409 are fixed on the gas guide pipe 402 and sealed. When the gas guide pipe 402 is transporting carbon dioxide, the temperature is reduced.

[0051] See also Figure 1 and Figure 7 Spectrometer 5 is used to analyze carbon dioxide 14The spectrometer 5 is a carbon-14 spectrometer. The incineration collection assembly 4 is connected to the air inlet of the spectrometer 5 via a tee 401. Specifically, the air inlet of the tee 401 is connected to the gas flow tube 402, and the air outlet of the tee 401 is connected to the air inlet of the spectrometer 5. The air inlet of the gas spectrometer 5 is provided with a first solenoid valve 404, which can control the carbon dioxide gas entering the spectrometer 5. To facilitate gas exhaust, the other end of the tee 401 is connected to an exhaust pipe 405, which is provided with a second solenoid valve 406. The second solenoid valve 406 can control the exhaust of gas from the tee 401.

[0052] See also Figure 1 and Figure 8 The second aspect of the present invention further provides a method for monitoring carbon-14 using the above-mentioned carbon-14 monitoring device in gaseous effluent, the monitoring method comprising the following steps:

[0053] S1, after mixing the gaseous effluent with oxygen and nitrogen, transport it to the oxidation combustion assembly 1 and heat it to 700-1000°C, fully burn it to generate gas containing carbon dioxide, and discharge it through the exhaust pipe 101;

[0054] S2, introducing the carbon dioxide-containing gas in the exhaust pipe 101 into the gas treatment component 2 to react with the alkali solution, and injecting calcium chloride into the gas treatment component to obtain calcium carbonate precipitate;

[0055] S3, placing the calcium carbonate precipitate in the drying and grinding assembly 3 for drying and grinding to obtain calcium carbonate powder;

[0056] S4, placing the calcium carbonate powder in the incineration and collection assembly 4 for incineration and pyrolysis to generate carbon dioxide gas, which is then transported to the spectrometer 5;

[0057] S5. Measure the carbon-14 concentration in the carbon dioxide using the spectrometer 5.

[0058] See also Figure 1 and Figure 2 Specifically, taking the gaseous effluent of a nuclear power plant as an example, step S1 first collects the gaseous effluent produced by the nuclear power plant and mixes it with oxygen and nitrogen. The mixing ratio is, for example, 1:3:8 for gaseous effluent, oxygen and nitrogen. The mixed gas is then injected into the oxidation combustion component 1 at a flow rate of 3 L / min and heated to 700-1000°C, for example, 700°C, 800°C, 900°C or 1000°C, so that the gaseous effluent is fully burned at high temperature, and all forms of carbon-14 are converted into carbon dioxide gas, which is discharged into the exhaust pipe 101. The oxygen in the mixed gas can provide oxygen atoms for the combustion reaction, and the gaseous effluent contains 14 Compounds of C (such as 14CH4, 14 CO) is completely oxidized to the target product 14 CO2 and maintain a high temperature reaction environment. Nitrogen as a carrier gas helps to evenly mix the gaseous effluent and oxygen and transport them through the reactor, ensuring that all gases have enough residence time in the high temperature zone to fully react. 14 CO2 and other gases (such as excess O2, other gases that react with oxygen, etc.) are discharged through the exhaust pipe 101. At the same time, nitrogen also acts as a diluent to dilute the concentration of gaseous effluent and oxygen to below a safe concentration to prevent explosion.

[0059] Step S2 is 14 In the CO2 purification step, since the gaseous effluent contains a variety of radioactive elements, the CO2 generated in the combustion reaction of step S1 is 14 CO2 will also produce other gases, so when detecting 14 CO2 14 Before the concentration of C is increased, it needs to be purified.

[0060] See also Figures 1 to 6 The specific process is as follows: the first switch valve 2041 and the second switch valve 2051 on the inlet pipe 204 and the outlet pipe 205 of the gas processing component 2 are opened, and part of the gas in the exhaust pipe 101 flows into the alkali solution cup 203 through the inlet pipe 204, reacts with the sodium hydroxide solution (for example, the concentration is 1.5 mol / L) therein to obtain sodium carbonate, and part of the unreacted gas is introduced into the exhaust pipe 101 through the outlet pipe 205. The flow rate A collected by the first flow sensor 2042 and the flow rate B collected by the second flow sensor 2052 are recorded. The flow rate A minus the flow rate B is the amount of carbon dioxide gas absorbed by the sodium hydroxide solution. Then, the total amount of gas discharged from the exhaust pipe 101 is measured by the flow sensor.

[0061] During the above process, the driving motor 206 is started, and the driving motor 206 drives the rotating shaft 207 to rotate the stirring frame 208 and the bracket 209, thereby stirring the sodium hydroxide solution in the alkali solution cup 203 and accelerating the absorption of carbon dioxide gas by the sodium hydroxide.

[0062] After the absolute difference between flow rate A and flow rate B reaches the target value, the first switch valve 2041 and the second switch valve 2051 are closed, the sealing cap 2014 is opened, and saturated calcium chloride is injected into the alkali solution cup 203 through the adding hopper 2013. The volume ratio of saturated calcium chloride to sodium hydroxide solution is 1:1. The saturated calcium chloride reacts with sodium carbonate to obtain calcium carbonate precipitate.

[0063] After the reaction is completed, the knob 2023 is turned to move the screw 2022 to move the tray 2021 downward, the transparent observation door 2015 is opened, the alkali solution cup 203 is taken out, and the calcium carbonate precipitate in the alkali solution cup 203 is separated using a Buchner funnel and filter paper;

[0064] Step S3 drying and grinding process: the calcium carbonate precipitate is placed in an oven of the drying and grinding component 3 and dried at 105° C. to a constant weight, and then the dried calcium carbonate is ground into a uniform calcium carbonate powder by a grinder so that the particle size is ≤0.1 mm.

[0065] See also Figure 7 , step S4 high purity 14 CO2 acquisition process: Calcium carbonate powder is placed in the incineration and collection component 4 for incineration and pyrolysis. At the same time, the first solenoid valve 404 is opened, the second solenoid valve 406 is closed, and the air pump 403 is started. The air pump 403 transports the carbon dioxide generated during the pyrolysis of the incineration and collection component 4 to the spectrometer 5 through the gas guide tube 402 and the three-way pipe 401 in sequence.

[0066] Step S5: Detection process: Measure the carbon dioxide content using spectrometer 5. 14 C concentration measurement: After the measurement is completed, the first electromagnetic valve 404 is closed and the second electromagnetic valve 406 is opened to discharge carbon dioxide from the exhaust pipe 405.

[0067] In summary, the present invention provides a device and method for monitoring carbon-14 in gaseous effluents, which is achieved by incinerating the gaseous effluents through an oxidizing combustion component to generate carbon dioxide. 14 The comprehensive collection of C, and then the measurement and calculation of the absolute difference between the inlet and outlet flow rates, to achieve effective calculation of carbon dioxide absorption, and thus to achieve accurate collection of carbon dioxide, for 14 The concentration of C is accurately measured to provide effective support, and then the absorption of carbon dioxide is extracted through the conversion of calcium carbonate. While convenient for storage, the output of carbon dioxide is achieved by pyrolysis of calcium carbonate, so that the spectrometer can be used for 14 The monitoring of C, which achieves quantitative carbon dioxide acquisition through chemical conversion, not only has the advantage of high monitoring accuracy, but also avoids the environmental unfriendly problems brought about by traditional monitoring methods.

[0068] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A device for monitoring carbon-14 in gaseous effluent, characterized in that: include: an oxidizing combustion component for incinerating the gaseous effluent to convert the gaseous effluent into a gas containing carbon dioxide; a gas treatment component, connected to the exhaust pipe of the oxidizing combustion component, the gas treatment component comprising an alkaline solution, the alkaline solution absorbing the carbon dioxide and reacting with the injected sodium chloride to form a calcium carbonate precipitate; A drying and grinding component, used for drying and grinding the calcium carbonate precipitate to convert the calcium carbonate precipitate into calcium carbonate powder; Incinerating the collection component to pyrolyze the calcium carbonate powder into carbon dioxide gas and collect it; A spectrometer is connected to the incineration collection component, and the spectrometer is used to measure the concentration of carbon-14 in carbon dioxide gas.

2. The device for monitoring carbon-14 in gaseous effluent according to claim 1, characterized in that: The gas processing assembly includes: a fixed cylinder, a lifting platform, an alkali liquid cup, an air inlet pipe and an air outlet pipe, the lifting platform is arranged inside the fixed cylinder, the alkali liquid cup is used to hold the alkali liquid and is arranged on the top of the lifting platform, the air inlet pipe and the air outlet pipe are respectively arranged on both sides of the top of the fixed cylinder, and one end of the air inlet pipe is connected to the exhaust pipe, and the other end is connected to the alkali liquid cup, and one end of the air outlet pipe is connected to the exhaust pipe, and the other end is connected to the alkali liquid cup; The air inlet pipe is provided with a first switch valve, a first flow sensor and a first one-way valve in sequence, and the air outlet pipe is provided with a second switch valve, a second flow sensor and a second one-way valve in sequence.

3. The device for monitoring carbon-14 in gaseous effluent according to claim 2, characterized in that: The gas processing assembly also includes a stirring device, which includes a drive motor, a rotating shaft, a stirring frame and a bracket. The drive motor is installed on the fixed cylinder, and the rotating shaft is arranged inside the fixed cylinder. One end of the rotating shaft is fixedly connected to the output end of the drive motor, and the other end extends along the axial direction of the fixed cylinder. The stirring frame is arranged on the rotating shaft, and the bracket is fixed to the bottom of the rotating shaft.

4. The device for monitoring carbon-14 in gaseous effluent according to claim 3, characterized in that: The rotating shaft is also provided with a diverter plate, which is arranged between the stirring frame and the bracket. The bottom end of the air inlet pipe passes through the diverter plate and extends to the bottom of the diverter plate. The diverter plate is provided with a plurality of diverter holes.

5. The device for monitoring carbon-14 in gaseous effluent according to claim 2, characterized in that: The lifting platform includes a tray and a screw rod, one end of the screw rod is rotatably connected to the tray, the other end of the screw rod passes through the bottom of the fixed tube and is threadedly connected to the fixed tube, and a knob is fixedly installed on one end of the screw rod passing through the bottom of the fixed tube.

6. The device for monitoring carbon-14 in gaseous effluent according to claim 5, characterized in that: The tray is provided with a receiving groove for the alkali liquid cup, the bottom of the alkali liquid cup is provided with a plurality of positioning blocks, and the receiving groove is provided with a plurality of positioning grooves cooperating with the positioning blocks; and / or, the top wall of the inner cavity of the fixing cylinder is provided with a sealing ring, and the sealing ring cooperates with the alkali liquid cup for sealing.

7. The device for monitoring carbon-14 in gaseous effluent according to claim 2, characterized in that: The top of the fixed cylinder is also provided with a feeding hopper communicated with the interior of the fixed cylinder, and the feeding hopper is connected with a sealing cap; and a transparent observation door is hinged on the fixed cylinder.

8. The device for monitoring carbon-14 in gaseous effluent according to claim 1, characterized in that: The incineration collection assembly is connected to the air inlet of the spectrometer through a tee, the air inlet of the tee is connected to a gas guide tube, the end of the gas guide tube away from the tee is connected to the air outlet of the incineration collection assembly through an air pump, and the air inlet of the spectrometer is provided with a first solenoid valve; The other end of the three-way pipe is connected to a drain pipe, and a second solenoid valve is provided on the drain pipe.

9. The device for monitoring carbon-14 in gaseous effluent according to claim 8, characterized in that: A condenser is provided inside the gas guide tube, and both ends of the condenser are connected to a cold liquid inlet pipe and a cold liquid outlet pipe respectively. The cold liquid inlet pipe and the cold liquid outlet pipe both pass through the gas guide tube and extend to the outside of the gas guide tube.

10. A method for monitoring carbon-14 in gaseous effluent, characterized in that: The carbon-14 monitoring device in the gaseous effluent according to any one of claims 1 to 9 is used for monitoring, and the monitoring method comprises the following steps: The gaseous effluent is mixed with oxygen and nitrogen, and then transported to the oxidation combustion component to be heated to 700-1000°C, and fully burned to generate gas containing carbon dioxide, which is discharged through the exhaust pipe; introducing the gas containing carbon dioxide in the exhaust pipe into a gas treatment component to react with alkali solution, and injecting calcium chloride into the gas treatment component to obtain calcium carbonate precipitate; placing the calcium carbonate precipitate in a drying and grinding assembly for drying and grinding to obtain calcium carbonate powder; The calcium carbonate powder is placed in an incineration and collection assembly for incineration and pyrolysis to generate carbon dioxide gas, which is then transported to a spectrometer; The concentration of carbon-14 in carbon dioxide is measured using a spectrometer.

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