Radioactive waste liquid treatment experimental device and its use method

Abstract

The present invention provides a radioactive waste liquid treatment experimental device and a method for using the same, wherein the radioactive waste liquid treatment experimental device comprises: a circulation tank; a preheating system, the preheating system is connected to the circulation tank and is used to preheat the feed liquid; a falling film evaporator, the feed liquid inlet of the falling film evaporator is connected to the feed liquid outlet of the preheating system, and the concentrated liquid outlet of the falling film evaporator is connected to the circulation tank; a steam condensing device, the steam inlet of the steam condensing device is connected to the steam outlet of the falling film evaporator, and the water outlet of the steam condensing device is connected to the circulation tank. The radioactive waste liquid treatment experimental device of the present invention and the method for using the same can demonstrate the complete treatment process of radioactive waste liquid, and can repeat the circulation experiment, and can conveniently obtain information such as temperature, pressure and image during the experiment.

Description

Technical Field

[0001] The invention relates to the technical field of waste liquid treatment, and in particular to a radioactive waste liquid treatment experimental device and a use method thereof. Background Art

[0002] Nuclear power plants and ships' offshore nuclear power systems generate a large amount of radioactive waste liquid during operation and maintenance, as well as during serious accidents. Nuclear contamination cleaning in nuclear defense and chemical engineering also generates radioactive waste liquid. Among the various treatment methods for radioactive waste liquid, evaporation concentration has a higher concentration factor and purification coefficient, especially for radioactive nuclides that are difficult to remove, such as cesium and strontium. The use of evaporation concentration can make these radioactive salts crystallize and precipitate, thereby greatly reducing the total amount of final waste and reducing the final disposal space and cost. Evaporation concentration is an indispensable link in the treatment of radioactive waste liquid at home and abroad, and is the prerequisite for the reduction, safety and stable disposal of radioactive waste liquid.

[0003] Research on the falling film evaporation kinetics, flow characteristics, heat and mass transfer characteristics, model and falling film fluctuation of radioactive liquid waste is beneficial to the reduction, safety and stable disposal of radioactive liquid waste. Therefore, an experimental device and method that can realize the research of radioactive liquid waste treatment process is needed. Summary of the invention

[0004] The invention provides a radioactive waste liquid treatment experimental device and a use method thereof, which are used to solve the problem of studying the radioactive waste liquid treatment process.

[0005] The present invention provides a radioactive waste liquid treatment experimental device, comprising:

[0006] Circulation tank;

[0007] A preheating system, the preheating system is connected to the circulation tank and is used to preheat the feed liquid;

[0008] A falling film evaporator, wherein a feed liquid inlet of the falling film evaporator is connected to a feed liquid outlet of the preheating system, and a concentrated liquid outlet of the falling film evaporator is connected to the circulation tank;

[0009] A steam condensing device, wherein the steam inlet of the steam condensing device is connected to the steam outlet of the falling film evaporator, and the water outlet of the steam condensing device is connected to the circulation tank.

[0010] According to the radioactive liquid waste treatment experimental device provided by the present invention, the falling film evaporation tube adopts outer tube falling film evaporation, and a wall temperature measuring device is arranged on the falling film evaporation tube. The wall temperature measuring device includes a polytetrafluoroethylene rod and a temperature sensor. At least one mounting groove is arranged on the outer wall of the polytetrafluoroethylene rod, and at least one temperature sensor is fixed in the mounting groove. The temperature sensor is coated with thermal conductive silicone grease and / or insulating paint, and the wall temperature measuring device is distributed in the falling film evaporation tube.

[0011] According to the radioactive liquid waste treatment experimental device provided by the present invention, the heat source supply form of the falling film evaporator is direct current power supply heating to provide uniform heat flow.

[0012] According to the radioactive waste liquid treatment experimental device provided by the present invention, the liquid outlet of the preheating system is connected to a first branch and a second branch; the outlet of the first branch is connected to the liquid inlet of the falling film evaporator, and a first electric valve is arranged on the first branch; the outlet of the second branch is connected to the circulation tank, and a second electric valve is arranged on the second branch.

[0013] According to the radioactive waste liquid treatment experimental device provided by the present invention, the preheating system includes a ball valve, a gear pump and a preheater arranged along the pipeline, the gear pump is used to provide power for the flow of the liquid, and the preheater is used to preheat the liquid.

[0014] According to the radioactive liquid waste treatment experimental device provided by the present invention, the preheating system further comprises a filter, the filter is arranged upstream of the gear pump, and the filter is used to filter impurities.

[0015] According to the radioactive liquid waste treatment experimental device provided by the present invention, the radioactive liquid waste treatment experimental device further comprises a vacuum pump, and the vacuum pump is connected to the vacuum port of the circulation tank.

[0016] According to the radioactive liquid waste treatment experimental device provided by the present invention, the radioactive liquid waste treatment experimental device further comprises an image acquisition device, and the image acquisition device is used to acquire image information of the feed liquid in the falling film evaporator.

[0017] The present invention also provides a method for using the radioactive waste liquid treatment experimental device as described in any one of the above, comprising the following steps:

[0018] The feed liquid in the circulation tank is pumped into the preheating system, and after the feed liquid is preheated by the preheating system, the feed liquid preheated by the preheating system is pumped into the falling film evaporator;

[0019] The concentrated liquid generated in the falling film evaporator is introduced into the circulation tank. At the same time, the steam generated in the falling film evaporator is condensed by the steam condensing device and the condensed water is introduced into the circulation tank.

[0020] According to the method of use provided by the present invention, the process of preheating the liquid feed by the preheating system and then pumping the liquid feed preheated by the preheating system into the falling film evaporator comprises:

[0021] Preheating the liquid feed by the preheating system;

[0022] The feed liquid temperature at the outlet position of the preheating system is obtained, and it is determined whether the feed liquid temperature reaches a preset value. If not, the process returns to the previous step; if so, the feed liquid preheated by the preheating system is introduced into the falling film evaporator.

[0023] The radioactive waste liquid treatment experimental device and the use method thereof provided by the present invention, the circulation tank, the preheating system, the falling film evaporator and the steam condensing device can realize the radioactive waste liquid treatment experiment, and provide conditions for the research of radioactive waste liquid treatment. In addition, the radioactive waste liquid treatment experimental device and the use method thereof provided by the present invention can circulate the radioactive waste liquid and realize multiple and long-term research on the radioactive waste liquid treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural schematic diagram of the radioactive waste liquid treatment experimental device provided by the present invention.

[0026] Reference numerals:

[0027] 1: circulation tank; 2: ball valve; 3: filter;

[0028] 4; gear pump; 5; preheater; 6; first electric valve;

[0029] 7; second electric valve; 8; falling film evaporator; 9; image acquisition device;

[0030] 10; steam condensing device; 11; vacuum pump; 12; temperature sensor;

[0031] 13; Pressure sensor. DETAILED DESCRIPTION

[0032] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0033] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0034] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0035] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0037] Combine the following Figure 1 , describing the radioactive liquid waste treatment experimental device of an embodiment of the present invention. Figure 1The arrow in the middle indicates the flow direction of the fluid in the pipeline.

[0038] The radioactive waste liquid treatment experimental device includes: a circulation tank 1, a preheating system, a falling film evaporator 8 and a steam cooling device. The circulation tank 1 is used to store the feed liquid, which is the radioactive waste liquid. The circulation tank 1 is provided with a temperature measuring device and a pressure measuring device to facilitate real-time detection of the pressure in the circulation tank 1.

[0039] The preheating system is connected to the circulation tank 1, and the feed liquid in the circulation tank 1 can enter the preheating system. The preheating system can preheat the feed liquid to make the feed liquid reach the set temperature, preparing for the falling film evaporator 8 to process the feed liquid.

[0040] The liquid inlet of the falling film evaporator 8 is connected to the preheating system, and the liquid heated by the preheating system and reaching the preset temperature can enter the falling film evaporator 8. The falling film evaporator 8 is arranged above the circulation tank 1, and the concentrated liquid outlet of the falling film evaporator 8 is connected to the circulation tank 1. The concentrated liquid formed by the falling film evaporator 8 treating the liquid directly flows into the circulation tank 1.

[0041] The steam inlet of the steam condensing device 10 is connected to the steam outlet of the falling film evaporator 8, and the water outlet of the steam condensing device 10 is connected to the circulation tank 1. The steam condensing device 10 can adopt a plate heat exchanger, and the steam condensing device 10 introduces cooling water to cool the steam, so that the steam condenses into liquid water and flows into the circulation tank 1.

[0042] The radioactive waste liquid treatment experimental device provided in the embodiment of the present invention can demonstrate the complete treatment process of radioactive waste liquid, and the concentrated liquid formed by the feed liquid and the liquid water formed by the condensation of steam can all flow back to the circulation tank 1, so that the radioactive waste liquid treatment experiment can be repeated. During the experiment, the temperature, pressure, image and other information of the equipment can be obtained, providing data reference for the actual treatment operation of radioactive waste liquid.

[0043] During the experiment, it is necessary to obtain the inner wall temperature of the heat exchange tube of the falling film evaporator 8, but in order to ensure the uniformity of the heat exchange tube, the temperature measuring device cannot be fixed on the inner wall of the heat exchange tube by welding. To solve the above problem, in one embodiment of the present invention, a wall temperature measuring device is provided on the falling film evaporator 8, and the wall temperature measuring device includes a polytetrafluoroethylene rod and a temperature sensor 12. At least one mounting groove is provided on the outer wall of the polytetrafluoroethylene rod, and the temperature sensor 12 is fixed in the mounting groove. The wall temperature measuring device is arranged in the falling film evaporator 8. The temperature inside the heat exchange tube can be measured by the temperature sensor 12 on the polytetrafluoroethylene rod. Taking the heat exchange tube with an inner diameter of 23mm as an example, a polytetrafluoroethylene rod with a diameter of 22mm is selected, and a mounting groove with a depth and width of 1mm is milled on the surface of the polytetrafluoroethylene rod by a milling machine. A thermocouple sensor is selected as the temperature sensor, and the thermocouple is embedded in the mounting groove of the polytetrafluoroethylene rod. Finally, the polytetrafluoroethylene rod is inserted into the heat exchange tube. In this way, the thermometer can be fixed, and the internal temperature of the heat exchange tube can be measured, and the normal installation of the equipment will not be affected.

[0044] Furthermore, the temperature sensor 12 is coated with thermally conductive silicone grease to enhance heat exchange performance. Furthermore, the temperature sensor 12 is coated with insulating paint to prevent the current from interfering with the measurement result of the temperature sensor 12.

[0045] In order to realize multi-point temperature monitoring of the heat exchange tubes in the falling film evaporator 8, multiple temperature sensors 12 can be arranged at intervals along the flow direction of the liquid. At the same time, a pressure sensor 13 can also be set on the falling film evaporator 8 to obtain the pressure information in the falling film evaporator 8 in real time.

[0046] In one embodiment of the present invention, the liquid feed outlet of the preheating system is connected to a first branch and a second branch. The outlet of the first branch is connected to the liquid feed inlet of the falling film evaporator 8, and a first electric valve 6 is provided on the first branch. When the first electric valve 6 is opened, the liquid feed in the preheating system can flow into the falling film evaporator 8. The outlet of the second branch is connected to the circulation tank 1, and a second electric valve 7 is provided on the second branch. When the second electric valve 7 is closed, the liquid feed in the preheating system can flow back into the circulation tank 1. This setting of the preheating system can realize the circulation heating of the liquid feed. When the liquid feed in the preheating system does not reach the set temperature, the first electric valve 6 can be closed and the second electric valve 7 can be opened, so that the preheating system circulates and heats the liquid feed; when the liquid feed reaches the set temperature, the second electric valve 7 can be closed and the first electric valve 6 can be opened, and the liquid feed can be introduced into the falling film evaporator 8 for treatment. A temperature sensor 12 may be provided on the preheating system to detect the temperature of the liquid in the preheating system, and in order to ensure that the liquid entering the falling film evaporator 8 reaches a preset temperature, the temperature sensor 12 should be provided at the liquid outlet of the preheating system.

[0047] In one embodiment of the present invention, the preheating system includes a ball valve 2, a gear pump 4 and a preheater 5 arranged along the pipeline. Two ball valves 2 can be provided, and the two ball valves 2 are respectively provided upstream of the gear pump 4 and between the gear pump 4 and the preheater 5. When the ball valve 2 is in an open state, the gear pump 4 is operated, and the gear pump 4 provides power for the flow of the feed liquid, so that the feed liquid enters the preheater 5 for heating. The feed liquid heated by the preheater 5 flows back to the circulation pump to prepare for the next heating process, or directly flows into the falling film evaporator 8 for treatment.

[0048] Furthermore, the preheating system further includes a filter 3, which is arranged upstream of the gear pump 4, and can be specifically arranged between the ball valve 2 and the gear pump 4. The filter 3 can remove impurities in the liquid feed to prevent the deposition of impurities on the equipment from affecting the normal operation of the equipment and causing damage to the equipment.

[0049] In one embodiment of the present invention, the radioactive liquid waste treatment device further comprises a vacuum pump 11, and the vacuum pump 11 is connected to the vacuum port of the circulation tank 1. When the vacuum pump 11 is in operation, it can produce a suction effect on the circulation tank 1 to maintain the vacuum degree of the system.

[0050] In one embodiment of the present invention, the radioactive liquid waste treatment device further includes an image acquisition device 9, which can be a high-speed camera, and image information in the radioactive liquid waste treatment device can be captured through the image acquisition device 9. In addition, in order to facilitate the collection of image information, a transparent material can be selected to make the outer shell of the falling film evaporator 8, or a transparent visual window can be set on the outer wall of the falling film evaporator 8.

[0051] The following describes the method for using the radioactive waste liquid treatment experimental device provided by the present invention. The method for using the radioactive waste liquid treatment experimental device described below can be referenced to the radioactive waste liquid treatment experimental device described above.

[0052] The method of using the radioactive waste liquid treatment experimental device includes the following steps:

[0053] S100, pumping the feed liquid in the circulation tank 1 into the preheating system, and after preheating the feed liquid by the preheating system, pumping the feed liquid preheated by the preheating system into the falling film evaporator 8.

[0054] Switch the ball valve 2 to the open state and start the gear pump 4. Under the action of the gear pump 4, the feed liquid in the circulation tank 1 is filtered by the filter 3 and flows into the preheater 5. Start the preheater 5 to heat the feed liquid in the preheater 5. When the feed liquid temperature at the feed liquid outlet of the preheater 5 reaches the preset value, the feed liquid is pumped into the falling film evaporator 8.

[0055] S200, introducing the concentrated liquid produced in the falling film evaporator 8 into the circulation tank 1, and at the same time, condensing the steam produced in the falling film evaporator 8 through the steam condensing device 10 and introducing the condensed water into the circulation tank 1.

[0056] In one embodiment of the present invention, the step S100 of preheating the liquid feed by the preheating system and then pumping the preheated liquid feed by the preheating system into the falling film evaporator 8 specifically includes:

[0057] S110, preheating the liquid feed by a preheating system;

[0058] The first control valve is closed, the second control valve and the ball valve 2 are opened, the gear pump 4 is started, and the feed liquid enters the preheating system for heating. The heated feed liquid can flow back to the circulation tank 1.

[0059] S120, obtaining the feed liquid temperature at the outlet position of the preheating system, and determining whether the feed liquid temperature reaches a preset value, if not, returning to step S100; if yes, introducing the feed liquid preheated by the preheating system into the falling film evaporator 8.

[0060] In one embodiment of the present invention, the method for using the radioactive waste liquid treatment experimental device further includes: starting the vacuum pump 11 to maintain a preset vacuum degree in the radioactive waste liquid treatment experimental device.

[0061] In another embodiment of the present invention, the method for using the radioactive waste liquid treatment experimental device also includes: starting the image acquisition device 9 to acquire and store image information of the slurry in the falling film evaporator 8 in real time; and / or obtaining and recording the temperature information of the radioactive waste liquid treatment experimental device in real time through the temperature sensor 12; and / or obtaining and recording the pressure information of the radioactive waste liquid treatment experimental device in real time through the pressure sensor 13.

[0062] The radioactive waste liquid treatment experimental device and the use method thereof provided by the present invention can carry out treatment experiments of radioactive liquid and are convenient for data collection, and can provide data reference for actual treatment operations of radioactive waste liquid.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radioactive waste liquid treatment experimental device, characterized in that: include: Circulation tank; A preheating system, the preheating system is connected to the circulation tank and is used to preheat the feed liquid; A falling film evaporator, wherein a feed liquid inlet of the falling film evaporator is connected to a feed liquid outlet of the preheating system, and a concentrated liquid outlet of the falling film evaporator is connected to the circulation tank; A steam condensing device, wherein the steam inlet of the steam condensing device is connected to the steam outlet of the falling film evaporator, and the water outlet of the steam condensing device is connected to the circulation tank; The falling film evaporator adopts outer tube falling film evaporation. The falling film evaporator is provided with a wall temperature measuring device, which includes a polytetrafluoroethylene rod and a temperature sensor. The polytetrafluoroethylene rod is inserted into the heat exchange tube. At least one mounting groove is provided on the outer wall of the polytetrafluoroethylene rod. At least one temperature sensor is fixed in the mounting groove. The temperature sensor is coated with thermal conductive silicone grease and / or insulating paint. The wall temperature measuring device is distributed in the falling film evaporator.

2. The radioactive waste liquid treatment experimental device according to claim 1, characterized in that: The heat source supply form of the falling film evaporator is direct current power supply heating to provide uniform heat flow.

3. The radioactive liquid waste treatment experimental device according to claim 1, characterized in that: The liquid outlet of the preheating system is connected to a first branch and a second branch; the outlet of the first branch is connected to the liquid inlet of the falling film evaporator, and a first electric valve is arranged on the first branch; the outlet of the second branch is connected to the circulation tank, and a second electric valve is arranged on the second branch.

4. The radioactive waste liquid treatment experimental device according to claim 1, characterized in that: The preheating system comprises a ball valve, a gear pump and a preheater arranged along the pipeline, the gear pump is used to provide power for the flow of the feed liquid, and the preheater is used to preheat the feed liquid.

5. The radioactive liquid waste treatment experimental device according to claim 4, characterized in that: The preheating system further comprises a filter, which is arranged upstream of the gear pump and is used for filtering impurities.

6. The radioactive liquid waste treatment experimental device according to claim 1, characterized in that: The radioactive liquid waste treatment experimental device also includes a vacuum pump, which is connected to the vacuum port of the circulation tank.

7. The radioactive liquid waste treatment experimental device according to claim 1, characterized in that: The radioactive waste liquid treatment experimental device further comprises an image acquisition device, and the image acquisition device is used to acquire image information of the feed liquid in the falling film evaporator.

8. A method for using the radioactive waste liquid treatment experimental device according to any one of claims 1 to 7, characterized in that: The following steps are involved: The feed liquid in the circulation tank is pumped into the preheating system, and after the feed liquid is preheated by the preheating system, the feed liquid preheated by the preheating system is pumped into the falling film evaporator; The concentrated liquid generated in the falling film evaporator is introduced into the circulation tank. At the same time, the steam generated in the falling film evaporator is condensed by the steam condensing device and the condensed water is introduced into the circulation tank.

9. The method of use according to claim 8, characterized in that: The step of preheating the feed liquid by the preheating system and then pumping the feed liquid preheated by the preheating system into the falling film evaporator comprises: Preheating the liquid feed by the preheating system; The feed liquid temperature at the outlet position of the preheating system is obtained, and it is determined whether the feed liquid temperature reaches a preset value. If not, the process returns to the previous step; if so, the feed liquid preheated by the preheating system is introduced into the falling film evaporator.

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