Carbon-14 on-line monitoring and absorbing device

Abstract

The utility model relates to a carbon-14 online monitoring and absorbing device, and belongs to the technical field of nuclear power station gas treatment. The device mainly comprises an absorption tank, a gas pipeline and a liquid circulation pipeline, a spraying device and a stirring device are respectively inserted into a liquid inlet and a stirrer opening in the top of the absorption tank; a gas inlet section of the gas pipeline comprises a carbon-14 gas source connecting pipeline as well as a flow regulating valve, a first pressure sensor and a first carbon dioxide monitor which are connected in series behind the carbon-14 gas source connecting pipeline, and downward bubblers are arranged at intervals after extending into the tank from a gas inlet in one side of the lower part of the absorption tank; the exhaust section comprises a steam-water separator ventilation flow channel and a second carbon dioxide monitor which are connected in series and start from an exhaust port in the upper part of the absorption tank; a liquid return port of the steam-water separator is connected to a liquid drop backflow port in the upper part of the absorption tank; and the liquid circulating pipeline is formed by connecting a centrifugal pump from a liquid outlet at the bottom of the absorption tank to a pipeline of a spraying device at a liquid inlet at the top of the absorption tank through a sampling valve with a sampling port. The device is good in absorption effect, safe and reliable.

Description

Technical Field

[0001] The utility model relates to carbon-14 monitoring and absorption, in particular to a carbon-14 online monitoring and absorption device, belonging to the technical field of nuclear power plant gas processing. Background Art

[0002] Carbon-14 is one of the radioactive gases emitted during the operation of nuclear power plants. Since the content of carbon-14 gas in the emission system is extremely small, at the ppm level, it is difficult to remove effectively.

[0003] A search shows that the Chinese patent document with application number 202210829963.7 discloses a liquid carbon-14 conversion and absorption device for a nuclear power plant, including a reaction vessel, a dryer and an alkaline solution absorption device connected in sequence by pipelines; the reaction vessel is respectively connected to an injection pump and a nitrogen inlet pipe, and a heating device is provided on the reaction vessel. This technical solution only converts and absorbs carbon-14 in the liquid, and the converted carbon dioxide is absorbed by an alkaline solution. Analysis shows that there are the following problems: 1) No reaction measures to enhance absorption are taken, so the absorption effect is not ideal; 2) The carbon-14 gas concentration is not effectively monitored, and the absorption parameters cannot be statistically analyzed.

[0004] In addition, the Chinese patent document with application number 202010013127.8 discloses a carbon dioxide absorption reactor and its online monitoring device, including a shell, an electric pump, a flow meter, and a spray device. However, analysis shows that the device uses an electric pump to circulate the absorbent to absorb carbon dioxide gas and detect the results, but there are the following problems: 1) It cannot be directly applied to the field of carbon-14 absorption and detection in the nuclear industry; 2) No effective measures have been taken to enhance the absorption reaction, and it is difficult to effectively remove ppm-level carbon-14; 3) There is no sampling link, and the data accuracy is insufficient if it relies solely on instruments and meters.

[0005] The Chinese patent document with application number 201911237942.0 discloses an online continuous monitoring device for carbon-14 in air and a method for calculating the activity concentration of carbon-14 in air. The device includes a gas pipeline and a collection unit sequentially arranged on the gas pipeline for quantitatively collecting gas, and converts all the carbon in different forms contained in the gas collected by the collection unit into CO 2 The tubular oxidation furnace is used to remove the non-CO in the gas treated by the tubular oxidation furnace. 2 The separation unit is used to separate and remove the components of CO 2 After cooling and solidification, the detection unit conducts online continuous detection of the activity concentration of carbon-14 in it; the different forms of carbon (including carbon-14) in the air are completely converted into CO through a tubular oxidation furnace. 2 , solid CO is obtained through separation unit and detection unit 2, collected in the measuring well, and the concentration of carbon-14 in the air is calculated by measuring the beta rays, with a recovery efficiency of about 90%. It is reported that through the system program and control, one-button operation can be achieved, unattended, stable and reliable, and suitable for online continuous monitoring of carbon-14 in the air. However, there are still the following problems: 1) It can only sample and monitor carbon-14 in the air, and cannot absorb carbon-14 efficiently; 2) It cannot sample and analyze the absorbent during the absorption process. Utility Model Content

[0006] The purpose of the utility model is to provide a carbon-14 online monitoring and absorption device with good absorption effect and convenient sampling and analysis in view of the problems existing in the prior art.

[0007] In order to achieve the above-mentioned purpose, the basic technical scheme of the utility model carbon-14 online monitoring and absorption device is: mainly composed of an absorption tank, a gas pipeline, and a liquid circulation pipeline;

[0008] The liquid inlet and the stirrer port at the top of the absorption tank are respectively equipped with a rotatable spray device and a stirring device;

[0009] The gas pipeline comprises an air intake section and an air exhaust section; the air intake section comprises a carbon-14 gas source connection pipeline and a flow regulating valve, a first pressure sensor, and a first carbon dioxide monitor connected in series thereafter, and extends from an air intake port on one side of the lower part of the absorption tank into the tank and is interposed with a bubbler facing downward; the air exhaust section comprises a series-connected steam-water separator ventilation channel and a second carbon dioxide monitor starting from an exhaust port at the upper part of the absorption tank, and the liquid return port of the steam-water separator is connected to a liquid droplet return port at the upper part of the absorption tank;

[0010] The liquid circulation pipeline is composed of a pipeline from a centrifugal pump at the bottom liquid outlet of the absorption tank to a spray device at the top liquid inlet of the absorption tank via a sampling valve with a sampling port.

[0011] During operation, the exhaust gas from the carbon-14 air source enters the absorption tank through the air intake section, and is absorbed by the bubbler and the added alkaline absorbent, with good absorption effect. The alkaline absorbent after absorption is driven by a centrifugal pump from the top of the absorption tank through a liquid circulation pipeline that can be sampled at any time and returned to the tank for spraying and recycling. The steam-water mixture containing alkaline substances discharged from the exhaust port of the absorption tank is separated and discharged by the steam-water separator to discharge the qualified gas, and the remaining alkaline substance absorbent liquid returns to the tank through the droplet reflux port. The signal output ends of the two carbon dioxide monitors are respectively connected to the data acquisition alarm device, so the carbon dioxide concentration in the gas before and after absorption can be measured in time. When the measured carbon dioxide concentration after absorption is higher than the set value, a signal prompting the replacement of the absorbent will be issued through the alarm device to ensure safety and reliability.

[0012] A further improvement of the utility model is that a first pneumatic ball valve is provided between the first carbon dioxide monitor and the air inlet, and a second pneumatic ball valve is provided between the liquid outlet and the centrifugal pump, so as to facilitate adjustment and control as appropriate.

[0013] A further improvement of the utility model is that a desalted water inlet for cleaning the tank body is arranged on the top of the absorption tank, so as to facilitate the cleaning of the tank body.

[0014] A further improvement of the utility model is that a feed port for filling alkaline absorbent is provided on the top of the absorption tank, so that the absorbent is added very conveniently.

[0015] The utility model is further improved in that: the top of the absorption tank is provided with a pressure sensor interface for installing and monitoring the internal pressure of the tank body.

[0016] A further improvement of the utility model is that a peephole is provided on one side of the absorption tank to facilitate real-time observation and monitoring.

[0017] A further improvement of the utility model is that the exhaust port and the liquid droplet return port are arranged at an angle of 90 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below in conjunction with specific embodiments and the accompanying drawings.

[0019] Figure 1 It is a structural schematic diagram of an embodiment of the utility model.

[0020] Figure 2 It is a schematic diagram of the structure viewed from above of FIG1 .

[0021] Figure 3 It is a side structural schematic diagram of Figure 1.

[0022] Figure 4 It is a schematic diagram of the three-dimensional structure of Figure 1.

[0023] Figure 5 It is a schematic diagram of the cross-sectional structure of the absorption tank in Figure 1.

[0024] In the figure: absorption tank 1, spray device 1-1, agitator 1-2, bubbler 1-3; pipeline 2-1, flow control valve 2-2, pipeline 2-3, first pressure sensor 2-4, pipeline 2-5, first carbon dioxide monitor 2-6, pipeline 2-7, pneumatic ball valve 2-8, pipeline 2-9, pipeline 2-10, steam-water separator 2-11, pipeline 2-12, pipeline 2-13, second carbon dioxide monitor 2-14, second pressure sensor 2-15; pipeline 3-1, pneumatic ball valve 3-2, pipeline 3-3, centrifugal pump 3-4, pipeline 3-5, pipeline 3-6, sampling valve 3-7, pneumatic ball valve 3-8, pipeline 3-9; air inlet a, exhaust port b, droplet reflux port c, liquid inlet d, liquid outlet e, sampling port f, peep port g, agitator port h, pressure sensor interface i, desalted water inlet j, feed port k. DETAILED DESCRIPTION Example

[0025] The carbon-14 online monitoring and absorption device of this embodiment is basically composed of the following: Figures 1 to 3 As shown, it is mainly composed of an absorption tank 1, a gas pipeline, and a liquid circulation pipeline, and the materials thereof are respectively stainless steel or alkaline corrosion resistant materials.

[0026] The top of the absorption tank 1 is provided with a liquid inlet d and an agitator port h of a rotatable spray device (B 3 / 8HH-SS20 316L model produced by Shanghai Feizhuo Company) 1-1 and an agitator 1-2 respectively inserted into the tank.

[0027] The gas pipeline contains an air intake section and an exhaust section. The air intake section includes a pipeline 2-1 connected to a carbon-14 gas source and a flow regulating valve 2-2, a pipeline 2-3, a first pressure sensor 2-4, a pipeline 2-5 equipped with a first carbon dioxide monitor 2-6, a pipeline 2-7, and a pneumatic ball valve 2-8 connected in series. The pipeline 2-9 then extends into the tank from an air intake a on one side of the lower part of the absorption tank. The portion of the pipeline 2-9 extending into the tank is provided with a downward-facing bubbler (HG-100-24 / 12 model of Shenzhen Hengge Company) 1-3.

[0028] The exhaust section includes the exhaust port b pipe 2-10 starting from the upper side of the absorption tank and the subsequent gas-water separator 2-11 ventilation channel, and the pipe 2-13 equipped with the second carbon dioxide monitor 2-14. The return liquid port of the gas-water separator 2-11 is connected to the droplet return port c at the upper part of the absorption tank 1 at an angle of 90° to the exhaust port b through the pipe 2-12. The pressure sensor interface i on the top of the absorption tank 1 is used to install a pressure sensor for monitoring the internal pressure of the tank body. The signal outputs of each pressure sensor and carbon dioxide monitor are respectively collected online to the control device through external data acquisition and alarm devices.

[0029] The liquid circulation pipeline is composed of a pipeline 3-1 originating from the liquid outlet e at the bottom of the absorption tank 1, passing through a pneumatic ball valve 3-2, a pipeline 3-3, a centrifugal pump 3-4, a pipeline 3-5, a pipeline 3-6, a sampling valve 3-7 with a sampling port f, a pneumatic ball valve 3-8, and a spray device 1-1 and a pipeline 3-9 connected to the tank through the liquid inlet d at the top of the absorption tank 1. Therefore, the liquid system circulation can be driven by a centrifugal pump.

[0030] The absorption tank 1 is supported by a steel support, and a peephole g is arranged on the side. The liquid inlet k on the top of the absorption tank 1 is used to add the alkaline liquid required for the absorption reaction.

[0031] In addition, the agitator cable extends into the tank from the agitator port h of the absorption tank 1. A second pressure sensor 2-15 is installed on the absorption tank 1, and its desalted water inlet j is used for cleaning the tank body.

[0032] During operation, the waste gas from the carbon-14 air source enters the absorption tank 1 through the air intake section, and is absorbed by reacting with the added alkaline absorbent through the bubbler 1-3. The absorbed alkaline absorbent from the liquid outlet e at the bottom of the absorption tank 1 is driven by the centrifugal pump 3-4, and returns to the tank from the liquid inlet d at the top of the absorption tank through the liquid circulation pipeline that can be sampled at any time for spraying and recycling. The steam-water mixture discharged from the exhaust port b of the absorption tank 1 contains alkaline absorbent components, which are separated by the steam-water separator 2-11 to meet the emission standards, and the remaining alkaline absorbent liquid is returned to the tank from the droplet reflux port c for continued use.

[0033] When the carbon dioxide monitor 2-14 detects that the carbon dioxide concentration in the absorbed gas is higher than the set value, the system triggers an alarm signal to prompt the replacement of the absorbent. The computer in the control device controls the opening degree of each pneumatic valve as appropriate based on the online output data of each pressure sensor and carbon dioxide monitor.

[0034] The test shows that since this example combines stirring, bubbling absorption and circulating spraying, it can effectively absorb ppm-level carbon-14 gas, and make full use of the circulation and separation and reuse of the alkaline absorbent. In addition, it has the following advantages:

[0035] 1) The liquid circulation system avoids inconsistent concentrations caused by precipitation and other problems, ensuring the accuracy of sampling data;

[0036] 2) It laid the foundation for combining carbon-14 absorption, monitoring and electrical control to achieve information-based control and monitoring;

[0037] 3) Reasonable setting of the steam-water separator can reduce the corrosion of the alkaline absorbent on valves, instruments and meters;

[0038] 4) A visual peep window is set on the side of the tank to observe bubbling, spraying and stirring, so as to monitor the entire reaction process;

[0039] 5) All flow-through parts are made of 316L material to avoid corrosion by alkaline absorbents and ensure the reliability and durability of the device;

[0040] 6) The alkaline absorbent is sucked into the tank in a vacuum form, and the pressure in the tank is controlled by a pressure sensor, which improves the convenience of absorbent filling and ensures the safety of operation.

[0041] The present utility model is not limited to the above-mentioned embodiments, and any technical solutions formed by equivalent replacement shall fall within the protection scope required by the present utility model.

Claims

1. A carbon-14 online monitoring and absorption device, characterized in that: It is mainly composed of absorption tank, gas pipeline and liquid circulation pipeline; The liquid inlet (d) and the stirrer port (h) at the top of the absorption tank are respectively plugged with a rotatable spray device and a stirring device; The gas pipeline comprises an air intake section and an air exhaust section; the air intake section comprises a carbon-14 gas source connection pipeline and a flow regulating valve, a first pressure sensor, and a first carbon dioxide monitor connected in series thereafter, and extends from an air intake port (a) on one side of the lower part of the absorption tank into the tank and is interposed with a bubbler facing downward; the air exhaust section comprises a series gas-water separator ventilation channel starting from an exhaust port (b) at the upper part of the absorption tank and a second carbon dioxide monitor, and the liquid return port of the gas-water separator is connected to a liquid droplet return port (c) at the upper part of the absorption tank; The liquid circulation pipeline is composed of a pipeline from a centrifugal pump at the liquid outlet (e) at the bottom of the absorption tank to a spray device at the liquid inlet (d) at the top of the absorption tank via a sampling valve with a sampling port (f).

2. The carbon-14 online monitoring and absorption device according to claim 1, characterized in that: A first pneumatic ball valve is provided between the first carbon dioxide monitor and the air inlet, and a second pneumatic ball valve is provided between the liquid outlet and the centrifugal pump.

3. The carbon-14 online monitoring and absorption device according to claim 2, characterized in that: The top of the absorption tank is provided with a deionized water inlet (j) for cleaning the tank body.

4. The carbon-14 online monitoring and absorption device according to claim 3, characterized in that: The top of the absorption tank is provided with a feed port (k) for adding alkaline absorbent.

5. The carbon-14 online monitoring and absorption device according to claim 4, characterized in that: The top of the absorption tank is provided with a pressure sensor interface (i) for installing and monitoring the internal pressure of the tank.

6. The carbon-14 online monitoring and absorption device according to claim 5, characterized in that: A peep hole (g) is provided on one side of the absorption tank.

7. The carbon-14 online monitoring and absorption device according to claim 6, characterized in that: The exhaust port and the liquid droplet return port are arranged at an angle of 90 degrees.

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