Method and system for the treatment of radioactive liquid waste

Abstract

Embodiments of the present application disclose a radioactive waste liquid treatment method. The method comprises: feeding radioactive waste liquid into an evaporator, circulating the radioactive waste liquid between a heating device and a separation device, heating the radioactive waste liquid by the heating device to make the radioactive waste liquid boil, and performing vapor-liquid separation on the boiled radioactive waste liquid in the separation device to generate secondary steam; introducing the secondary steam generated by evaporation of the radioactive waste liquid into a steam compression device, compressing and heating the secondary steam by the steam compression device, and then delivering the secondary steam to the heating device as a first heat source of the heating device to exchange heat with the radioactive waste liquid; and discharging residual liquid generated by concentration of the radioactive waste liquid in the evaporator; and wherein, during the evaporation of the radioactive waste liquid, the secondary steam generated by evaporation of the radioactive waste liquid is sampled to determine a decontamination factor of the radioactive waste liquid treatment system. In addition, embodiments of the present application also provide a radioactive waste liquid treatment system.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of radioactive waste treatment, and particularly to a radioactive waste liquid treatment method and system. BACKGROUND

[0002] At present, the treatment of radioactive waste liquid usually uses evaporation concentration technology. The technology mainly sends preheated radioactive waste liquid into an evaporator, heats the radioactive waste liquid in the evaporator by using high-temperature steam, and makes the radioactive waste liquid evaporate and separate into steam and concentrated liquid. The steam can be directly discharged after condensation, and the concentrated liquid needs to be further treated subsequently.

[0003] However, the traditional evaporation concentration technology mostly uses a special heat source, needs to continuously input new steam to heat the feed liquid, and has large energy consumption. Moreover, for a large amount of secondary steam generated in the evaporator, the secondary steam is directly condensed by using cooling water, and the heat energy cannot be recycled and the cooling water is consumed. SUMMARY

[0004] Embodiments of the present application provide a radioactive waste liquid treatment method. The method comprises: feeding radioactive waste liquid into an evaporator, the evaporator comprising a heating device and a separation device, and the radioactive waste liquid circulating between the heating device and the separation device; wherein the heating device heats the radioactive waste liquid to make the radioactive waste liquid boil, and the boiled radioactive waste liquid is subjected to vapor-liquid separation in the separation device to generate secondary steam, so as to concentrate the radioactive waste liquid; introducing the secondary steam generated by evaporation of the radioactive waste liquid into a steam compression device, and after the secondary steam is compressed and heated by using the steam compression device, the secondary steam is delivered to the heating device to serve as a first heat source of the heating device and exchange heat with the radioactive waste liquid; discharging residual liquid formed after the radioactive waste liquid in the evaporator is concentrated; wherein during the evaporation process of the radioactive waste liquid, the secondary steam generated by evaporation of the radioactive waste liquid is sampled to determine the decontamination factor of the radioactive waste liquid treatment system.

[0005] The embodiment of the present application also provides a radioactive waste liquid treatment system. The system comprises: an evaporator for evaporative concentration of radioactive waste liquid; the evaporator comprises: a heating device, a heating cavity is formed in the heating device, a flow channel for heating steam is provided, a liquid flow channel for the flow of the radioactive waste liquid is arranged in the heating cavity, and the heating steam can exchange heat with the radioactive waste liquid to perform heating treatment on the radioactive waste liquid; a separation device, which is connected with the liquid flow channel of the heating device, is used for performing vapor-liquid separation on the boiled radioactive waste liquid after the heating treatment to form secondary steam, so that the radioactive waste liquid is concentrated; a circulating pipeline, which is connected with the separation device and the heating device respectively, is used for providing a channel for the circulation of the radioactive waste liquid between the heating device and the separation device; a steam compression device, which is arranged between the separation device and the heating cavity, is used for compressing and heating the secondary steam to serve as a first heat source of the heating device; a discharge port, which is arranged on the circulating pipeline, is used for discharging residual liquid formed after the concentration of the radioactive waste liquid; and a sampling device, in which a sample flow channel is arranged, is connected to a gas path upstream of a steam inlet of the steam compression device, and is used for sampling the secondary steam generated by the evaporation of the radioactive waste liquid.

[0006] The method and system in the embodiment can recycle the heat energy of the secondary steam generated by the evaporation of the radioactive waste liquid, reduce the use amount of cooling water, and greatly reduce the energy consumption in the evaporation treatment process of the radioactive waste liquid. Meanwhile, sampling and detecting the secondary steam generated by the evaporation of the radioactive waste liquid can verify the purification coefficient of the treatment system. BRIEF DESCRIPTION OF DRAWINGS

[0007] Other objects and advantages of the present application will be more fully apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings.

[0008] Figure 1 FIG. 1 is a structural schematic diagram of a radioactive waste liquid treatment system according to an embodiment of the present application.

[0009] Figure 2 FIG. 2 is a structural schematic diagram of a separation device according to an embodiment of the present application.

[0010] Figure 3 FIG. 3 is a structural schematic diagram of a purification device according to an embodiment of the present application.

[0011] Figure 4 FIG. 4 is a structural schematic diagram of a sampling device according to an embodiment of the present application.

[0012] It should be noted that the drawings are not necessarily drawn to scale, but are merely intended to show the illustrative nature of the drawings. DETAILED DESCRIPTION

[0013] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only one embodiment of the present application, but not all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0014] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings understood by those of ordinary skill in the art to which the present application belongs. If the descriptions of "first", "second", etc. are involved throughout the text, the "first", "second", etc. descriptions are only used to distinguish similar objects, and cannot be understood as indicating or implying the relative importance, the order of precedence or implicitly indicating the number of the indicated technical features. It should be understood that the data of "first", "second", etc. descriptions can be interchanged under appropriate circumstances. If "and / or" appears throughout the text, it means that three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B schemes are satisfied at the same time. In addition, in order to facilitate the description, spatial relative terms such as "above", "below", "top", "bottom", etc. are used here, which are only used to describe the spatial positional relationship of one device or feature with other devices or features as shown in the figure, and it should be understood to include different orientations in use or operation in addition to the orientation shown in the figure.

[0015] In the operation, decontamination and decommissioning of nuclear industrial facilities, a large amount of radioactive waste liquid is inevitably produced. Since the amount of radioactive waste liquid is large, especially the medium and low level radioactive waste liquid, it needs to be treated to reduce the volume of radioactive waste liquid and facilitate solidification treatment. The embodiments of the present application evaporate the radioactive waste liquid. The radioactive intensity of water vapor formed by evaporation of the radioactive waste liquid is reduced, and the condensed and cooled radioactive waste liquid can be directly discharged. The volume of the concentrated liquid remaining after evaporation of the radioactive waste liquid is greatly reduced, and the concentrated liquid is stored after solidification treatment, thereby reducing the storage volume of the radioactive waste liquid and facilitating subsequent transportation.

[0016] Figure 1 The structural schematic diagram of a radioactive waste liquid treatment system according to an embodiment of the present application is shown. As shown in FIG. 1, the radioactive waste liquid treatment system comprises a waste liquid tank 1, a waste liquid pump 2, a waste liquid evaporator 3, a waste liquid condenser 4, a waste liquid storage tank 5, a waste liquid evaporator control system 6 and a waste liquid condenser control system 7. Figure 1As shown, the radioactive waste liquid treatment system in this embodiment of the invention includes an evaporator, a vapor compression device 20, and a residual vapor storage container 42. The evaporator heats the radioactive waste liquid to boil and evaporate it into steam, which is then concentrated to form residual vapor. The vapor compression device 20 is connected to the evaporator and compresses and heats the steam formed by the evaporation of the radioactive waste liquid in the evaporator to form heating steam. This heating steam is then transported to the evaporator to exchange heat with the radioactive waste liquid within the evaporator, serving as the primary heat source for the evaporation of the radioactive waste liquid. The residual vapor storage container 42 is connected to the evaporator and is used to receive and store the residual vapor formed after the radioactive waste liquid in the evaporator has been concentrated.

[0017] like Figure 1 As shown, the evaporator in this embodiment is a split-type evaporator, which includes a heating device 11 and a separation device 12. The heating device 11 has a heating chamber with a liquid flow channel inside. The liquid flow channel is used for the flow of radioactive waste liquid, and the high-temperature gas flowing in the heating chamber can exchange heat with the radioactive waste liquid in the liquid flow channel to heat the radioactive waste liquid. The separation device 12 is connected to the liquid flow channel of the heating device 11 and is used to perform vapor-liquid separation on the boiling radioactive waste liquid, thereby concentrating the radioactive waste liquid.

[0018] Furthermore, a circulation pipe is provided between the liquid flow channel of the heating device 11 and the separation device 12 to provide a channel for the circulation of radioactive waste liquid between the heating device 11 and the separation device 12. Specifically, the separation device 12 is located above the heating device 11. The heating device 11 has an inlet at its bottom and an outlet at its top. The separation device 12 has an outlet at its bottom and an inlet on its side wall. The circulation pipe includes a first circulation pipe 13 and a second circulation pipe 14. The first circulation pipe 13 connects the inlet at the bottom of the heating device 11 and the outlet at the bottom of the separation device 12. The second circulation pipe 14 connects the outlet at the top of the heating device 11 and the inlet on the side wall of the separation device 12, thereby allowing the radioactive waste liquid in the separation device 12 to flow downwards into the heating device 11, and the radioactive waste liquid in the heating device 11 to flow upwards into the separation device 12, forming a circulation.

[0019] In some embodiments, the separation device 12 is disposed above the heating device 11, and the radioactive waste liquid can circulate between the heating device 11 and the separation device 12 by relying on its own sealing difference. Specifically, after the radioactive waste liquid is heated to boiling in the heating device 11, it flows upward into the separation device 12 due to the decrease in density, while the radioactive waste liquid in the separation device 12 increases in density due to evaporation and concentration, and can flow downward into the heating device 11, thereby forming a natural circulation between the heating device 11 and the separation device 12, ensuring the continuity of the dynamic circulation of the radioactive waste liquid.

[0020] In some embodiments, a circulating pump 82 is arranged on the first circulating pipeline 13, for controlling the forced circulation of the radioactive waste liquid between the heating device 11 and the separation device 12. Compared with the natural circulation, the evaporation capacity of the evaporator to the radioactive waste liquid and the heat transfer efficiency can be increased, and the processing efficiency of the radioactive waste liquid can be improved.

[0021] It should be noted that the evaporator in the embodiment is provided with a working liquid level. After the feed is fed into the evaporator to the working liquid level, heating and circulation are started. In addition, when the radioactive waste liquid processing system is normally operated, the radioactive waste liquid in the evaporator also needs to be kept at the working liquid level. In the embodiment, the liquid inlet of the separation device 12 is arranged at the working liquid level of the evaporator.

[0022] In some embodiments, the discharge port of the evaporator is arranged on the first circulating pipeline 13 and located between the circulating pump 82 and the heating device 11. The discharge pipe 103 is connected between the discharge port and the residual liquid storage container 42. The residual liquid evaporated and concentrated in the evaporator is discharged into the residual liquid storage container 42 through the discharge pipe 103 for storage, so as to facilitate subsequent processing. In addition, a discharge valve can be arranged on the discharge pipe 103, for controlling the discharge speed of the evaporator.

[0023] In some embodiments, the feed port of the evaporator can also be arranged on the first circulating pipeline 13, located between the circulating pump 82 and the separation device 12, and higher than the bottom of the heating device 11. In the embodiment, the discharge speed is controlled to remain unchanged by the discharge valve, and the supply speed of the radioactive waste liquid fed into the evaporator is controlled to remain unchanged. Continuous feeding and discharging can be maintained, so that the running state of the entire processing system remains stable.

[0024] As shown in FIG. 1, Figure 1 The processing system in the embodiment further includes a feeding device 41 connected with the feed port of the evaporator. The feeding device 41 is used for storing the radioactive waste liquid to be processed, and the radioactive waste liquid in the feeding device 41 can be fed into the evaporator for evaporation processing. Specifically, the feeding device 41 and the first circulating pipeline 13 are connected by a feed pipeline 101. The feed pipeline 101 is provided with a feeding pump 81. The radioactive waste liquid in the feeding device 41 can be sequentially conveyed into the evaporator through the feed pipeline 101 and the first circulating pipeline 13.

[0025] In addition, the processing system further comprises a reflux pipeline 102, one end of which is connected to the feeding device 41, and the other end is connected to the feeding pipeline 101. At least part of the radioactive waste liquid in the feeding pipeline 101 can flow back to the feeding device 41 through the reflux pipeline 102. In this embodiment, a reflux valve is arranged on the reflux pipeline 102. The flow of radioactive waste liquid in the reflux pipeline 102 can be controlled by adjusting the reflux valve, thereby controlling the feeding flow of radioactive waste liquid into the evaporator, preventing the pressure of radioactive waste liquid in the feeding pipeline 101 from fluctuating, and ensuring the smooth feeding of radioactive waste liquid.

[0026] Further, the gas inlet of the steam compression device 20 is connected to the separation device 12, and the gas outlet after the steam compression device 20 is connected to the heating cavity of the heating device 11. The boiled radioactive waste liquid after heating is evaporated in the separation device 12 to form secondary steam, which is discharged from the top of the separation device 12 to the steam compression device 20. The steam compression device 20 compresses and heats the secondary steam to form heated steam, which is then transported to the heating cavity of the heating device 11 to exchange heat with the radioactive waste liquid in the liquid flow channel of the heating device 11, thereby achieving the heating treatment of the radioactive waste liquid.

[0027] In this embodiment, the steam compression device 20 is used to recover the latent heat of the secondary steam generated during the evaporation of the radioactive waste liquid, so that the pressurized and heated secondary steam is used as a heat source to heat the subsequent feeding of radioactive waste liquid. Therefore, it is not necessary to set up a special boiler room for heating, which reduces the energy consumption of the radioactive waste liquid evaporation treatment.

[0028] As shown in Figure 1 The radioactive waste liquid processing system in this embodiment further comprises a steam generation device 30. The steam generation device 30 can generate high-temperature water vapor, and is connected to the evaporator, thereby providing a second heat source for the heating of the radioactive waste liquid in the evaporator. The steam generation device 30 can be used as a heat source for the evaporator during the start-up process of the processing system, or can provide supplemental steam to the evaporator during the normal operation of the processing system as a heat loss supplement.

[0029] Specifically, the steam generator 30 has a water-containing cavity and an electric heating element inside, which heats the water in the cavity to form high-temperature steam. In this embodiment, the steam generator 30 is connected to the heating cavity of the heating device 11, thereby providing a heat source for the heating device 11 to heat the radioactive waste liquid. The high-temperature steam generated by the steam generator 30 enters the heating cavity of the heating device 11 and exchanges heat with the radioactive waste liquid, causing the radioactive waste liquid to boil. In addition, the steam generated by the steam generator 30 and the pressurized and heated secondary steam exchange heat in the heating device 11 to form a condensate with a certain temperature, which then flows back into the steam generator 30, thereby keeping the liquid level in the steam generator 30 stable.

[0030] In some embodiments, the steam generated by the steam generator 30 can be delivered to the inlet of the steam compressor 20 to prevent surge in the steam compressor 20. Compared to the conventional method of circulating superheated steam from the outlet of the steam compressor 20 to the inlet of the steam compressor 20, in this embodiment, high-temperature and high-pressure heating steam is delivered to the heating device 11 for heat exchange before entering the steam generator 30. This allows the steam in the steam generator 30 to enter the steam compressor 20 from the inlet, thus avoiding excessively high inlet temperature of the steam compressor 20.

[0031] like Figure 1 As shown, the processing system also includes a preheating device. The evaporator is connected to the preheating device. When evaporating radioactive waste liquid, the preheating device is used to preheat the radioactive waste liquid before it is conveyed to the evaporator. In this embodiment, the preheating device includes a first preheating device 51, which is disposed between the feeding device 41 and the evaporator for preheating the radioactive waste liquid. In this embodiment, the radioactive waste liquid is preheated in the first preheating device 51 before being conveyed to the evaporator. Specifically, the first preheating device 51 can be a heat exchanger. The first preheating device 51 is also connected to a steam generator 30, which provides a heat source for the first preheating device 51.

[0032] In this embodiment, the radioactive waste liquid is transported to the tube side of the first preheating device 51, and the hot water in the steam generator 30 is transported to the shell side of the first preheating device 51 to exchange heat with the radioactive waste liquid, thereby preheating the radioactive waste liquid at room temperature, reducing the temperature difference between the radioactive waste liquid and the phase transition temperature, and improving the efficiency of radioactive waste liquid treatment.

[0033] In addition, the processing system in the embodiment can further include a condensate storage container 43 connected with the first preheating device 51, for receiving and storing the condensate in the first preheating device 51 after heat exchange with the radioactive waste liquid. In some embodiments, the processing system can not be provided with the condensate storage container 43, and the condensate formed in the first preheating device 51 after heat exchange can be directly discharged.

[0034] In some embodiments, the condensate discharge pipeline of the first preheating device 51 is further provided with a cooling device. When the condensate discharged from the first preheating device 51 has a high temperature, the cooling device can cool and lower the temperature of the condensate before discharging. In the embodiment, the cooling device can be a heat exchanger, and cooling water is used as the heat source of the heat exchanger to exchange heat with the condensate to lower the temperature of the condensate.

[0035] In some embodiments, the preheating device further includes a second preheating device 52, which is arranged between the first preheating device 51 and the evaporator, for re-preheating the radioactive waste liquid, so that the temperature of the radioactive waste liquid is raised to near the boiling point (for example, 98°C) before being fed into the evaporator, thereby improving the evaporation separation efficiency of the radioactive waste liquid.

[0036] In the embodiment, the radioactive waste liquid preheated for the first time is transported to the tube side of the second preheating device 52, and steam is transported to the shell side of the second preheating device 52 to exchange heat with the radioactive waste liquid, thereby re-preheating the radioactive waste liquid and further raising the temperature of the radioactive waste liquid to improve the processing efficiency. The second preheating device 52 is connected with the steam generating device 30, and the condensate is formed after the steam exchanges heat with the radioactive waste liquid, and the condensate flows into the steam generating device 30 to supplement the water level in the steam generating device 30.

[0037] It should be noted that, during the start-up stage, the steam used for preheating in the second preheating device 52 can be the steam generated by the steam generating device 30. The shell side of the second preheating device 52 is also connected with the heating cavity of the heating device 11. During normal operation, the steam used for preheating in the second preheating device 52 can be the heated steam generated by the steam compression device 20, which is transported into the second preheating device 52 after passing through the heating cavity of the heating device 11 to exchange heat with the radioactive waste liquid. In addition, during normal operation, the steam generating device 30 can also provide steam for the second preheating device 52 to compensate for the heat loss of the system.

[0038] In some embodiments, a trap is further arranged between the second preheating device 52 and the steam generating device 30, and a trap (not shown in the figure) can also be arranged between the heating device 11 and the steam generating device 30, which is used for vapor-liquid separation of the condensate flowing out of the second preheating device 52 and the heating device 11, so as to prevent the condensate from carrying gas into the steam generating device 30 and affecting the normal operation of the steam generating device 30.

[0039] There is a large amount of non-condensable gas (for example, air) in the equipment before the treatment system is operated, and a small amount of non-condensable gas is also generated when the radioactive waste liquid is heated during the operation of the system. In order to remove the non-condensable gas in the treatment system, the treatment system in the embodiment is further provided with a non-condensable gas discharge and recovery device 70. As shown in Figure 1 The non-condensable gas discharge and recovery device 70 is connected with the second preheating device 52, which is used for discharging the non-condensable gas in the second preheating device 52 and recovering the steam discharged by the second preheating device 52, so as to avoid that too much non-condensable gas in the second preheating device 52 affects the heat transfer efficiency.

[0040] Specifically, the non-condensable gas discharge and recovery device 70 is connected with the shell side of the second preheating device 52, cooling water is introduced into the non-condensable gas discharge and recovery device 70, and the gas in the shell side of the second preheating device 52 is discharged into the non-condensable gas discharge and recovery device 70 and exchanges heat with the cooling water in the non-condensable gas discharge and recovery device 70. Among them, the steam in the discharged gas is condensed to form condensate by the cooling water, and the condensate can be directly discharged, while the non-condensable gas is directly discharged from the non-condensable gas discharge and recovery device 70. It should be noted that the non-condensable gas in the embodiment of the application refers to the gas that will not be condensed by the cooling water, for example, air and the like.

[0041] In the embodiment, the non-condensable gas discharge and recovery device 70 is also connected with the condensate storage container 43, and the condensate formed by the steam in the non-condensable gas discharge and recovery device 70 can be recovered into the condensate storage container 43. When the condensate storage container 43 is not arranged, the condensate generated in the non-condensable gas discharge and recovery device 70 is directly discharged.

[0042] In addition, the non-condensable gas discharge and recovery device 70 in the embodiment can also be connected with the heating device 11, which is used for discharging the non-condensable gas in the heating cavity of the heating device 11 and recovering the steam discharged by the heating device 11, so as to avoid that too much non-condensable gas in the heating device 11 affects the heat transfer efficiency.

[0043] In some embodiments, the heating device 11 is provided with at least two exhaust ports. One of the exhaust ports is connected with the second preheating device 52, and is used to discharge the gas in the heating device 11 to the second preheating device 52, so that the steam in the second preheating device 52 exchanges heat with the radioactive waste liquid; the other exhaust port is connected with the non-condensable gas discharge and recovery device 70, and is used to directly discharge the gas in the heating device 11 to the non-condensable gas discharge and recovery device 70, so as to directly discharge the non-condensable gas in the heating device 11.

[0044] In addition, the at least two exhaust ports are arranged at different heights of the heating device 11, and are respectively connected with exhaust valves, so as to discharge the gas at different positions in the heating device 11, and thus discharge the non-condensable gas.

[0045] Similarly, the second preheating device 52 is provided with at least two exhaust ports, and the at least two exhaust ports are arranged at different heights of the second preheating device 52 and are respectively connected with exhaust valves, so as to discharge the gas at different positions in the second preheating device 52, and thus discharge the non-condensable gas.

[0046] It should be noted that the processing system in the embodiment can be provided with a cooling water storage container, which can store and provide cooling water. The cooling water can not only cool the condensed liquid discharged from the first preheating device 51, but also cool the steam in the non-condensable gas discharge and recovery device 70. In addition, the cooling water can also cool the oil tank and motor of the steam compression device 20, the mechanical seal of the circulating pump 82 and other pumps in the processing system.

[0047] As shown in FIG. 1, Figure 2 In some embodiments, the separation device 12 is provided with a first demister 121, which is used to remove the radioactive waste liquid carried by the secondary steam generated by the evaporation of the radioactive waste liquid, and prevent the liquid droplets carried by the secondary steam from entering the steam compression device and causing pollution. Specifically, the first demister 121 can be arranged at the top of the separation device 12, above the working liquid level of the evaporator.

[0048] In some embodiments, the first demister 121 includes a wave plate demister 1211, which includes a plurality of wave plates arranged in the axial direction of the separation device 12, and the plurality of wave plates have gaps therebetween. When the secondary steam generated by the evaporation of the radioactive waste liquid flows through the wave plate demister 1211, the secondary steam can flow out of the gaps between the plurality of wave plates, and the liquid droplets carried by the secondary steam collide with the wave plates when passing through the turning portions of the wave plates and are attached to the surfaces of the wave plates, thereby achieving the demisting effect on the secondary steam and realizing the primary purification of the secondary steam.

[0049] In some embodiments, the first demister 121 comprises a wire mesh demister 1212 made of metal wire mesh. When the secondary steam generated by the evaporation of the radioactive waste liquid flows through the wire mesh demister 1212, the liquid droplets carried by the secondary steam are attached to the metal wire due to resistance, thereby playing a role in separating the liquid droplets and achieving primary purification of the secondary steam.

[0050] Optionally, one of the wave plate demister 1211 and the wire mesh demister 1212 can be selected to be arranged in the separation device 12. The wave plate demister 1211 and the wire mesh demister 1212 can also be arranged in the separation device 12 at the same time. The wire mesh demister 1212 can be arranged below the wave plate demister 1211. The use of two types of demisters for purifying the secondary steam can greatly increase the demisting effect.

[0051] As shown in Figure 1 , the processing system in the embodiment further comprises a purification device 60. The purification device 60 is connected between the separation device 12 and the steam compression device 20, and is used for purifying the secondary steam generated by the evaporation of the radioactive waste liquid in the separation device 12. After removing the radioactive substances mixed in the secondary steam, the secondary steam is transported to the steam compression device 20, thereby preventing the radioactive substances mixed in the secondary steam from causing radioactive contamination to the steam compression device 20 and the downstream steam generating device 30.

[0052] Specifically, as shown in Figure 3 , the purification device 60 is provided with a second demister 61 for demisting the secondary steam entering the purification device 60, thereby removing the radioactive waste liquid mixed in the secondary steam and achieving purification of the secondary steam. In some embodiments, the second demister 61 can be a wire mesh demister. The liquid droplets mixed in the secondary steam can be attached to the wire mesh demister, thereby reducing the liquid mist carried by the secondary steam.

[0053] As shown in Figure 1 and Figure 3 , the top of the purification device 60 is further provided with a spraying member 62. The spraying member 62 sprays in the purification device 60, and is used for washing the secondary steam entering the purification device 60, so that the radioactive liquid droplets carried by the secondary steam flow down with the spraying liquid, thereby removing the radioactive substances mixed in the secondary steam and achieving the purpose of purifying the secondary steam.

[0054] In some embodiments, the spray element 62 is disposed above the second demister 61. While spraying and cleaning the secondary steam, the spray element 62 can also spray and clean the second demister 61, causing radioactive droplets adhering to the second demister 61 to flow with the spray liquid to the bottom of the purification device 60. Furthermore, the spray radiation angle of the spray element 62 can be no less than 90 degrees, thereby radiating spray in all directions to cover the entire interior of the purification device 60, achieving spray cleaning of the entire demister and the inner surface of the purification device 60.

[0055] Furthermore, the bottom of the purification device 60 contains spray liquid, and the spray element 62 is connected to the drain port at the bottom of the purification device 60 through a spray liquid pump 84. The spray liquid pump 84 can transport the spray liquid at the bottom of the purification device 60 to the spray element 62, so that the spray element 62 can use the spray liquid contained in the purification device 60 to spray the secondary steam, which not only ensures the purification effect, but also realizes the recycling of the spray liquid.

[0056] like Figure 1 As shown, the purification device 60 is connected to the steam generator, which can transport the condensate in the steam generator to the purification device 60 as a spray liquid. While ensuring the purification effect, it also avoids the need to set up a special water storage tank or water source to achieve spray cleaning, thus simplifying the treatment system.

[0057] Furthermore, when the concentration of radioactive material in the spray liquid contained in the purification device 60 reaches a predetermined concentration threshold, the spray liquid needs to be replaced with new spray liquid to ensure the purification effect of the spray liquid on the secondary steam. Specifically, the spray liquid in the purification device 60 can be discharged into the radioactive waste liquid feeding device 41 to facilitate the evaporation treatment of the radioactive spray liquid. Then, the condensate in the steam generator 30 is transported to the purification device 60 to replenish the spray liquid used for spray cleaning.

[0058] like Figure 1 and Figure 3 As shown, the purification device 60 also includes a packing layer 63, which is located below the second demister 61 and above the surface of the spray liquid. The secondary steam entering the purification device 60 first passes through the packing layer 63, which enhances the contact and mass transfer between the secondary steam and the spray liquid, thus improving purification efficiency. Exemplarily, the packing layer 63 includes two fixed sieve plates and packing material disposed between them, thereby fixing the packing material within the purification device 60. Optionally, the packing material in this embodiment can be Pall ring packing. Due to its perforated ring walls, it greatly improves the utilization rate of the internal space and surface area of ​​the ring, resulting in low airflow resistance, uniform liquid distribution, and advantages such as high throughput, low resistance, and high separation efficiency.

[0059] In the embodiment, the gas inlet of the purification device 60 is arranged below the filler layer 63, so that the secondary steam enters the purification device 60 and sequentially flows through the filler layer 63, the second demister 61 and the spray 62. Through the combined action of the filler, the demister and the spray cleaning, the purification effect of the secondary steam is improved. In addition, the liquid level of the spray liquid contained in the purification device 60 can be higher than the gas inlet, so that the secondary steam flows upward after being cleaned by the spray liquid, further improving the purification effect.

[0060] As shown in Figure 1 the embodiment, the processing system further includes a condensate pump 83, the inlet of the condensate pump 83 is connected with the steam generating device 30, and the condensate pump 83 is used to transport the water heated to a certain temperature in the steam generating device 30. Specifically, the outlet of the condensate pump 83 can be connected to the first preheating device 51, and used to transport the hot water in the steam generating device 30 to the shell side of the first preheating device 51 to preheat the radioactive waste liquid. The outlet of the condensate pump 83 can also be connected to the purification device 60 to supplement the spray liquid for spray cleaning of the purification device 60.

[0061] In addition, a spray point is arranged on the outlet pipeline 104 of the steam compression device 20, and the outlet of the condensate pump 83 can also be connected to the spray point to spray and cool the superheated steam in the outlet pipeline 104 of the steam compression device 20, so as to reduce the temperature of the superheated steam, convert it into saturated steam, and facilitate the provision of the saturated steam as a heat source to the heating device 11 and the second preheating device 52.

[0062] As shown in Figure 1 the embodiment, the processing system further includes a sampling device 90 connected to the gas path before the steam inlet of the steam compression device 20, which is used to sample the secondary steam generated by the evaporation of the radioactive waste liquid, and facilitate the detection of the secondary steam to judge the purification capacity of the processing system.

[0063] As shown in Figure 4 the embodiment, the sampling device 90 is formed with a cooling cavity 91, and a coolant circulates in the cooling cavity 91. At least one sample flow channel 92 is arranged in the cooling cavity 91, and the sample flow channel 92 is connected with the gas path upstream of the steam compression device 20 to provide a channel for the flow of the secondary steam. The secondary steam in the sample flow channel 92 can be condensed into a liquid sample by the coolant, and the concentration of the liquid sample can be detected to judge the purification coefficient of the processing system.

[0064] In some embodiments, at least one collection port 93 is arranged on the sampling device 90, and the collection port 93 is connected with the sample flow channel 92 to collect the liquid sample formed by the cooling of the secondary steam in the sample flow channel 92.

[0065] Specifically, the separation device 12 is provided with a first sampling port and a second sampling port, the first sampling port is located below the first demister 121, and the second sampling port is located above the first demister 121. The sample flow channel 92 includes a first sample flow channel and a second sample flow channel, wherein the first sample flow channel is connected with the first sample port and is used for sampling the secondary steam in the separation device 12 which has not been subjected to defoaming treatment by the first demister 121; and the second sample flow channel is connected with the second sample port and is used for sampling the secondary steam in the separation device 12 which has been subjected to defoaming treatment after flowing through the first demister 121. In the embodiment, the secondary steam before and after the first demister 121 is sampled and detected, and the purification capacity of the evaporator can be judged according to the concentration of the secondary steam.

[0066] Further, the sample flow channel 92 further includes a third sample flow channel connected to the outlet of the purification device 60 to sample the secondary steam at the outlet of the purification device 60. In the embodiment, the purification coefficient of the treatment system can be verified by detecting the concentration of the condensate in the condensate storage container. Meanwhile, the secondary steam at the outlet of the purification device 60 is sampled and detected in the embodiment, and the purification coefficient and the decontamination factor of the treatment system can be verified according to the concentration of the secondary steam, and it is judged whether the condensate storage container or the sampling port thereof is contaminated.

[0067] The treatment system in the embodiment can be used to evaporate and concentrate the radioactive waste liquid, thereby reducing the volume of the radioactive waste liquid, so as to facilitate the later storage and solidification treatment of the radioactive waste liquid.

[0068] In addition, the embodiment of the present application also provides a radioactive waste liquid treatment method, which can be realized by using the treatment system in any of the above embodiments. The treatment method in the embodiment specifically includes the following steps.

[0069] In step S10, the radioactive waste liquid is fed into the evaporator, and the radioactive waste liquid circulates between the heating device 11 and the separation device 12; wherein the heating device 11 heats the radioactive waste liquid to make it boil, and the boiled radioactive waste liquid is subjected to vapor-liquid separation in the separation device 12 to generate secondary steam, so as to concentrate the radioactive waste liquid.

[0070] In step S20, the secondary steam generated by evaporating the radioactive waste liquid is introduced into the vapor compression device 20, and after being compressed and heated by the vapor compression device 20, it is delivered to the heating device 11 to serve as the first heat source of the heating device 11 and exchange heat with the radioactive waste liquid.

[0071] In step S30, the residual liquid formed after the radioactive waste liquid is concentrated in the evaporator is discharged.

[0072] Step S40, during the evaporation of the radioactive liquid waste, the secondary steam generated by the evaporation of the radioactive liquid waste is sampled to determine the decontamination factor of the radioactive liquid waste treatment system.

[0073] In the present embodiment, the steam generated by the evaporation of the radioactive liquid waste is compressed and heated by the steam compression device 20 to form heated steam, and the heated steam is used as the heat source of the evaporator, so as to recover the latent heat of evaporation of the radioactive liquid waste and reduce the energy consumption. The steam generation device 30 is only used as the heat source of the evaporator during the start-up process, and provides a small amount of compensation steam during the normal operation process to compensate for the heat loss of the treatment system and maintain the stable operation of the system.

[0074] In addition, the traditional method for verifying the decontamination factor of the treatment system is to detect the concentration of the condensate recovered by the treatment system, while the present embodiment can assist in verifying the decontamination factor of the treatment system by sampling and detecting the secondary steam generated by the evaporation of the radioactive liquid waste.

[0075] In some embodiments, the secondary steam generated by the evaporation of the radioactive liquid waste can be sampled to obtain a steam sample, and then the steam sample is cooled to form a liquid sample, the concentration of the liquid sample is detected, and the decontamination factor of the radioactive liquid waste treatment system is determined according to the concentration of the liquid sample.

[0076] In some embodiments, the radioactive liquid waste enters the first preheating device 51 through the feed pump 81, and is preheated to about 70°C by the condensate of the secondary steam generated after the radioactive liquid waste is heated in the steam generation device 30, and then is sent to the second preheating device 52. In the second preheating device 52, the radioactive liquid waste is further preheated to above 90°C by the heated steam generated by the compression of the purified secondary steam in the heating device 11.

[0077] Further, the radioactive liquid waste passes through the second preheating device 52 and enters the evaporator, and the flow speed of the radioactive liquid waste is improved by driving the radioactive liquid waste to flow by the circulating pump 82. The radioactive liquid waste is heated to boiling in the heating device 11 and is subjected to vapor-liquid separation in the separation device 12.

[0078] In some embodiments, before the secondary steam generated by the evaporation of the radioactive liquid waste in the separation device 12 exits the separation device, the secondary steam is subjected to defoaming treatment by the first defoamer 121 to avoid the secondary steam entraining radioactive droplets and entering the steam compression device 20.

[0079] In the embodiment, the steam not treated by the defoaming device can be sampled to obtain a first steam sample, and the steam treated by the defoaming device can be sampled to obtain a second steam sample. The first steam sample and the second steam sample are cooled to form a first liquid sample and a second liquid sample, respectively. The concentrations of the first liquid sample and the second liquid sample are detected, and the decontamination factor of the evaporator is determined according to the concentrations of the first liquid sample and the second liquid sample.

[0080] In the embodiment, the purification capacity of the evaporator can be determined by sampling and detecting the secondary steam before and after the first defoaming device.

[0081] In some embodiments, the secondary steam generated by evaporating the radioactive waste liquid can be further purified by the purification device before being introduced into the steam compression device 20. Specifically, the secondary steam flowing out of the separation device passes through the purification device 60, and is further purified by the filler layer 63, the second defoaming device 61 and the spray in the purification device 60, so as to further avoid radioactive substances from entering the steam compression device 20. The secondary steam out of the purification device 60 is directly introduced into the steam compression device 20 for compression and heating.

[0082] In the embodiment, the secondary steam at the outlet of the purification device 60 can be sampled to detect the concentration of radioactive substances in the secondary steam, and the actual decontamination factor of the radioactive waste liquid treatment system is determined according to the concentration of radioactive substances in the secondary steam.

[0083] Specifically, the secondary steam at the outlet of the purification device 60 can be sampled to obtain a third steam sample, the third steam sample is cooled to form a third liquid sample, the concentration of the third liquid sample is detected, and the actual decontamination factor of the radioactive waste liquid treatment system is determined according to the concentration of the third liquid sample.

[0084] In the embodiment, the purified secondary steam passes through the steam compression device 20 for pressurization and heating, and is then introduced into the heating cavity of the heating device 11 as heating steam. Part of the heating steam enters the shell side of the second preheating device 52 as a heat source of the evaporator and the second preheating device 52, respectively, to complete the evaporation of the radioactive waste liquid and the preheating process. The newly generated secondary steam from the evaporation of the radioactive waste liquid is purified and then introduced into the steam compression device 20 for heating and pressurization, to heat the subsequent radioactive waste liquid as a heat source, forming a continuous circulation process.

[0085] The secondary steam compressed and heated to heat the radioactive waste liquid is condensed into condensed liquid at about 112℃, and flows into the steam generating device 30. Most of the condensed liquid is transported to the first preheating device 51 by the condensed liquid pump 83 to preheat the radioactive waste liquid at room temperature to about 70℃. After cooling, the condensed liquid is transported to the condensed liquid storage container 43 as purified liquid.

[0086] In addition, the condensate pump 83 sends a portion of the condensate at about 112°C into the outlet pipe 104 of the vapor compression device 20 to eliminate the superheat degree of the pressurized and heated secondary steam, and the portion of the condensate is vaporized at the outlet of the vapor compression device 20 to reduce the temperature of the secondary steam to saturated steam entering the heating device 11 to heat the radioactive waste liquid. A small amount of the condensate is also sent into the purification device 60 to be used as spray liquid, and during operation, the secondary steam is circulated and sprayed in the purification device 60 by the spray liquid pump 84 to ensure the purification effect.

[0087] A large amount of non-condensable gas exists in the equipment before the system is operated, and a small amount of non-condensable gas is generated when the radioactive waste liquid is heated during the operation of the system. At least one exhaust port is arranged at the upper part and the lower part of the heating device 11 and the second preheating device 52, respectively, and an exhaust valve is connected to each exhaust port. During the operation of the system, the exhaust valve is opened at a fixed time to exhaust the non-condensable gas in the system to improve the heat exchange efficiency of the equipment.

[0088] In the embodiment, the steam generation device 30 is the starting heat source of the entire system. When the system is started, the steam generation device 30 is operated at full power. After a large amount of secondary steam is generated in the evaporator and the vapor compression device 20 is normally operated, the steam generation device 30 is switched to low-power operation to provide compensation steam for the system and maintain stable operation of the system.

[0089] In some embodiments, the condensate formed by the secondary steam generated by the evaporation of the radioactive waste liquid and the heat exchange of the radioactive waste liquid can be collected into the condensate storage container 43, that is, the condensate in the first preheating device 51 and the non-condensable gas exhaust and recovery device 70 is collected into the condensate storage container 43.

[0090] The concentration of the condensate in the condensate storage container 43 can be detected to determine the decontamination factor measurement value of the radioactive waste liquid treatment system.

[0091] Further, the decontamination factor measurement value of the radioactive waste liquid treatment system can be compared with the actual decontamination factor. If the decontamination factor measurement value is less than the actual decontamination factor, it is determined that the condensate storage container 43 is contaminated.

[0092] For the embodiments of the present application, it should also be noted that the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments without conflict.

[0093] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for treating radioactive liquid waste, characterized by, The method comprises the following steps: feeding radioactive waste liquid into an evaporator, the evaporator comprising a heating device and a separation device, the radioactive waste liquid circulating between the heating device and the separation device; wherein the heating device heats the radioactive waste liquid to make the radioactive waste liquid boil, the boiled radioactive waste liquid is subjected to vapor-liquid separation in the separation device to generate secondary steam, so as to concentrate the radioactive waste liquid; introducing the secondary steam generated by evaporating the radioactive waste liquid into a steam compression device, compressing and heating the secondary steam by the steam compression device, and then conveying the secondary steam to the heating device as a first heat source of the heating device to exchange heat with the radioactive waste liquid; discharging the residual liquid generated by concentrating the radioactive waste liquid in the evaporator; wherein during the evaporation of the radioactive waste liquid, sampling the secondary steam generated by evaporating the radioactive waste liquid to determine the decontamination factor of the radioactive waste liquid treatment system; a purification device is arranged between the separation device and the steam compression device; the method further comprises the following steps: before introducing the secondary steam separated by the separation device into the steam compression device, purifying the secondary steam by using the purification device; a spraying member is arranged at the top of the purification device, the spraying member sprays in the purification device to clean the secondary steam entering the purification device; a second demister is arranged in the purification device to demist the secondary steam entering the purification device; the spraying member is arranged above the second demister.

2. The method of claim 1, wherein, Further comprising: sampling the secondary steam generated by evaporating the radioactive waste liquid to obtain a steam sample; cooling the steam sample to form a liquid sample; detecting the concentration of the liquid sample, and determining the decontamination factor of the radioactive waste liquid treatment system according to the concentration of the liquid sample.

3. The method of claim 2, wherein, Further comprising: a first demister is arranged in the separation device, and the first demister is used to demist the secondary steam generated by evaporating the radioactive waste liquid in the separation device before the secondary steam leaves the separation device.

4. The method of claim 3, wherein, Further comprising: sampling the secondary steam without the demisting treatment to obtain a first steam sample; sampling the secondary steam after the demisting treatment to obtain a second steam sample; cooling the first steam sample and the second steam sample to form a first liquid sample and a second liquid sample, respectively; detecting the concentrations of the first liquid sample and the second liquid sample; determining the decontamination factor of the evaporator according to the concentrations of the first liquid sample and the second liquid sample.

5. The method of claim 1, wherein, Further comprising: sampling the secondary steam at the outlet of the purification device; detecting the concentration of radioactive substances in the secondary steam, and determining the actual decontamination factor of the radioactive waste liquid treatment system according to the concentration of radioactive substances in the secondary steam.

6. The method of claim 5, wherein, Further comprising: sampling the steam at the outlet of the purification device to obtain a third steam sample; cooling the third steam sample to form a third liquid sample; detecting the concentration of the third liquid sample; determining the actual decontamination factor of the radioactive waste liquid treatment system according to the concentration of the third liquid sample.

7. The method of claim 5, wherein, Also comprising: The secondary steam generated by evaporating the radioactive waste liquid is used to heat the radioactive waste liquid, and the condensed liquid formed by condensing the heated radioactive waste liquid is collected into a condensed liquid storage container.

8. The method of claim 7, wherein, Also comprising: Detecting the concentration of the condensed liquid in the condensed liquid storage container to determine the decontamination factor measurement value of the radioactive waste liquid treatment system.

9. The method of claim 8, wherein, Also comprising: Comparing the decontamination factor measurement value of the radioactive waste liquid treatment system with the actual decontamination factor, and if the decontamination factor measurement value is less than the actual decontamination factor, it is determined that the condensed liquid recovery device is contaminated.

10. A radioactive liquid waste treatment system, comprising: For implementing the radioactive waste liquid treatment method according to any one of claims 1-9, comprising: An evaporator for evaporating and concentrating the radioactive waste liquid; the evaporator comprises: A heating device, a heating cavity is formed in the heating device for providing a flow channel for heating steam, a liquid flow channel for the flow of radioactive waste liquid is arranged in the heating cavity, and the heating steam can exchange heat with the radioactive waste liquid to heat treat the radioactive waste liquid; A separation device connected to the liquid flow channel of the heating device for vapor-liquid separation of the boiling radioactive waste liquid after heating treatment to form secondary steam and concentrate the radioactive waste liquid; A circulating pipeline connected to the separation device and the heating device for providing a channel for the circulation of the radioactive waste liquid between the heating device and the separation device; A steam compression device arranged between the separation device and the heating cavity for compressing and warming the secondary steam to serve as the first heat source of the heating device; A discharge port arranged on the circulating pipeline for discharging the residual liquid formed after the concentration of the radioactive waste liquid; A sampling device, a sample flow channel is arranged in the sampling device, the sample flow channel is connected to the gas path upstream of the steam inlet of the steam compression device, and the sampling device is used for sampling the secondary steam generated by evaporating the radioactive waste liquid; The system further comprises a purification device arranged between the separation device and the steam compression device for purifying the secondary steam separated by the separation device; A spray element is arranged at the top of the purification device, the spray element sprays in the purification device for cleaning the secondary steam entering the purification device; A second demister is arranged in the purification device for defoaming treatment of the secondary steam entering the purification device; the spray element is arranged above the second demister.

11. The system of claim 10, wherein, The sampling device is formed with a cooling cavity, at least one sample flow channel is arranged in the cooling cavity, and a coolant circulates in the cooling cavity, the coolant is used for heat exchange with the secondary steam in the sample flow channel to condense the secondary steam.

12. The system of claim 11, wherein, At least one collection port is arranged on the sampling device, the collection port is connected to the sample flow channel, and the collection port is used for collecting the liquid sample formed by cooling the secondary steam in the sample flow channel.

13. The system of claim 12, wherein, A first demister is arranged in the separation device, and the first demister is used for defoaming treatment of the secondary steam.

14. The system of claim 13, wherein, The separation device is provided with a first sampling port and a second sampling port, the first sampling port is located below the first demister, and the second sampling port is located above the first demister.

15. The system of claim 14, wherein, The sampling device is also provided with a first sample flow channel and a second sample flow channel; wherein, The first sample flow channel is connected with the first sample port, and is used for sampling the steam in the separation device which has not been subjected to demisting treatment by the first demister; The second sample flow channel is connected with the second sample port, and is used for sampling the steam in the separation device which has been subjected to demisting treatment by the first demister.

16. The system of claim 13, wherein, The third sample flow channel in the sampling device is connected to the outlet of the purification device, so as to sample the secondary steam at the outlet of the purification device.

Images