CN115966328A - Radioactive waste liquid treatment method and system - Google Patents

Abstract

The embodiment of the invention discloses a radioactive waste liquid treatment method. The method comprises the following steps: continuously feeding the radioactive spent liquor into the evaporator, the radioactive spent liquor circulating between the heating device and the separation device; wherein, the heating device heats the radioactive waste liquid to boil the radioactive waste liquid, and the boiled radioactive waste liquid is subjected to vapor-liquid separation in the separation device to generate secondary vapor so as to concentrate the radioactive waste liquid; introducing secondary steam generated by evaporating the radioactive waste liquid into a steam compression device, compressing and heating the secondary steam by using the steam compression device, and then conveying the secondary steam to a heating device to be used as a first heat source of the heating device to exchange heat with the radioactive waste liquid; and continuously discharging the concentrated radioactive waste liquid in the evaporator, and controlling the discharge flow of the concentrated radioactive waste liquid to ensure that the radioactive waste liquid is concentrated to a preset multiple. In addition, the embodiment of the invention also provides a radioactive liquid waste treatment system.

Description

Radioactive waste liquid treatment method and system

technical field

Embodiments of the present invention relate to the technical field of radioactive waste treatment, and in particular to a method and system for treating radioactive waste liquid.

Background technique

At present, the treatment of radioactive waste liquid usually uses evaporation and concentration technology. This technology mainly sends the preheated radioactive waste liquid into the evaporator, and uses high-temperature steam to heat the radioactive waste liquid in the evaporator, so that the radioactive waste liquid evaporates. Separation into steam and concentrated liquid, in which the steam can be discharged directly after condensation, and the concentrated liquid needs to be further processed later.

However, most of the traditional evaporation and concentration technologies use a special heat source, which needs to continuously input new steam to heat the feed liquid, which consumes a lot of energy. Moreover, for the large amount of secondary steam generated in the evaporator, the cooling water is directly used to condense, and the heat energy cannot be recovered and the cooling water is consumed.

Contents of the invention

An embodiment of the present invention provides a method for treating radioactive waste liquid. The method includes: continuously feeding the radioactive waste liquid into the evaporator, the evaporator includes a heating device and a separation device, and the radioactive waste liquid circulates between the heating device and the separation device; wherein, the heating device heats the radioactive waste liquid to make The radioactive waste liquid boils, and the boiling radioactive waste liquid undergoes vapor-liquid separation in the separation device to generate secondary steam to concentrate the radioactive waste liquid; the secondary steam generated by evaporating the radioactive waste liquid is introduced into the vapor compression device, and the vapor compression device is used to After the secondary steam is compressed and heated, it is sent to the heating device as the first heat source of the heating device to exchange heat with the radioactive waste liquid; the concentrated radioactive waste liquid in the evaporator is continuously discharged, and the concentrated radioactive waste liquid is controlled The output flow rate is to ensure that the radioactive waste liquid is concentrated to a predetermined multiple.

The embodiment of the invention also provides a radioactive waste liquid treatment system. The system includes: an evaporator for evaporating and concentrating the radioactive waste liquid; the evaporator includes: a heating device, the heating device is formed with a heating chamber for providing a flow channel for the heating steam, and the heating chamber is provided with a device for the flow of the radioactive waste liquid The liquid flow path of the heating steam can exchange heat with the radioactive waste liquid to heat the radioactive waste liquid; the separation device, the separation device is connected with the liquid flow path of the heating device, and is used for the boiling of the radioactive waste liquid after heat treatment Carry out vapor-liquid separation to form secondary steam to concentrate the radioactive waste liquid; circulation pipes, which are respectively connected to the separation device and the heating device, are used to provide passages for the radioactive waste liquid to circulate between the heating device and the separation device; vapor compression The device is arranged between the separation device and the inlet of the heating chamber, and the vapor compression device is used to compress the secondary vapor to raise the temperature and serve as the first heat source of the heating device; the residual liquid storage container is connected to the heating device for receiving and store the raffinate formed after the evaporation of the radioactive waste liquid; wherein, a liquid discharge valve is arranged between the raffinate storage container and the heating device to control the discharge flow rate of the raffinate.

By adopting the method and system in this embodiment, the heat energy of the secondary steam generated by the evaporation of the radioactive waste liquid can be recovered and utilized, the consumption of cooling water can be reduced, and the energy consumption in the process of evaporating the radioactive waste liquid can be greatly reduced.

Description of drawings

Other objects and advantages of the present invention will be apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, and may help to have a comprehensive understanding of the present invention.

Fig. 1 is a schematic structural diagram of a radioactive waste liquid treatment system according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a separation device according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a purification device according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a sampling device according to an embodiment of the present invention.

It should be noted that the drawings are not necessarily drawn to scale, but are only shown in a schematic manner that does not affect readers' understanding.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Apparently, the described embodiment is one embodiment of the present application, but not all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the application shall have the usual meanings understood by those skilled in the art to which the application belongs. If the descriptions such as "first" and "second" are involved in the whole text, the descriptions such as "first" and "second" are only used to distinguish similar objects, and cannot be understood as indicating or implying their relative importance, sequence, etc. The order or the number of technical features indicated by implicit indication should be understood as "first", "second" and other described data can be interchanged under appropriate circumstances. If "and/or" appears throughout the text, it means to include three parallel plans, taking "A and/or B" as an example, including plan A, or plan B, or a plan that satisfies both A and B. In addition, for ease of description, spatially relative terms, such as "above", "below", "top", "bottom", etc., may be used herein to describe only one device or feature as shown in the figures in relation to other devices or features. The spatial relationship of features should be understood to also encompass different orientations in use or operation than those shown in the figures.

During the operation, decontamination and decommissioning of nuclear industrial facilities, a large amount of radioactive waste liquid is inevitably produced. Due to the large amount of radioactive waste liquid, especially the medium and low level radioactive waste liquid, it needs to be treated to reduce The volume of radioactive waste liquid is convenient for solidification treatment. In the embodiment of the present invention, the radioactive waste liquid is evaporated, and the radioactive intensity of the water vapor formed by the evaporation of the radioactive waste liquid is reduced, and can be discharged directly after condensation and cooling, while the volume of the remaining concentrated liquid after the radioactive waste liquid is evaporated will be greatly reduced. It is stored after solidification treatment, thereby reducing the storage volume of radioactive waste liquid and facilitating subsequent transportation.

Fig. 1 shows a schematic structural diagram of a radioactive waste liquid treatment system according to an embodiment of the present invention. As shown in FIG. 1 , the radioactive waste liquid treatment system in the embodiment of the present invention includes an evaporator, a vapor compression device 20 and a distillation raffinate storage container 42 . Wherein, the evaporator is used to heat the radioactive waste liquid, so that the radioactive waste liquid boils and evaporates to form steam, and after evaporation, the radioactive waste liquid is concentrated to form a distilled raffinate. The vapor compression device 20 is connected to the evaporator, which can compress and heat up the steam formed by the evaporation of the radioactive waste liquid in the evaporator to form heating steam, and transport the heating steam to the evaporator, so that the heating steam and the radioactive waste liquid in the evaporator can be separated. Heat exchange, as the first heat source for the evaporation of radioactive waste liquid. The raffinate storage container 42 is connected with the evaporator, and is used for receiving and storing the raffinate formed after the radioactive waste liquid in the evaporator is evaporated and concentrated.

As shown in FIG. 1 , the evaporator in this embodiment is a split evaporator, and the evaporator includes a heating device 11 and a separating device 12 . Wherein, the heating device 11 is formed with a heating cavity, and a liquid flow channel is arranged in the heating cavity, and the liquid flow channel is used for the flow of radioactive waste liquid, and the high-temperature gas flowing in the heating cavity can exchange heat with the radioactive waste liquid in the liquid flow channel. To heat the radioactive waste liquid. The separation device 12 communicates with the liquid channel of the heating device 11 and is used for separating the vapor and liquid of the boiling radioactive waste liquid to realize the concentration of the radioactive waste liquid.

Further, a circulation pipeline is provided between the liquid passage of the heating device 11 and the separation device 12 to provide a channel for the circulation of the radioactive waste liquid between the heating device 11 and the separation device 12 . Specifically, the separation device 12 is arranged above the heating device 11, the bottom of the heating device 11 is provided with a liquid inlet, the top is provided with a liquid outlet, the bottom of the separation device 12 is provided with a liquid outlet, and the side wall is provided with a liquid inlet. The circulation pipeline comprises a first circulation pipeline 13 and a second circulation pipeline 14, the first circulation pipeline 13 is connected between the liquid inlet at the bottom of the heating device 11 and the liquid outlet at the bottom of the separation device 12, and the second circulation pipeline 14 is connected at the heating between the liquid outlet on the top of the device 11 and the liquid inlet on the side wall of the separation device 12, so that the radioactive waste liquid in the separation device 12 flows downward into the heating device 11, and the radioactive waste liquid in the heating device 11 flows upward to the separation device 12 to form a circulation.

In some embodiments, the separation device 12 is arranged above the heating device 11 , and the radioactive waste liquid can circulate between the heating device 11 and the separation device 12 relying on its own sealing difference. Specifically, after the heating device 11 is heated to boiling, the radioactive waste liquid flows upward into the separation device 12 due to the decrease in density, and the radioactive waste liquid in the separation device 12 becomes dense due to evaporation and concentration, and can flow downward. to 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.

In some embodiments, the first circulation pipeline 13 is provided with a circulation pump 82, which is used to control the forced circulation of the radioactive waste liquid between the heating device 11 and the separation device 12. The treatment capacity and heat transfer efficiency of liquid can be improved, and the treatment efficiency of radioactive waste liquid can be improved.

It should be noted that the evaporator in this embodiment is provided with a working liquid level, and heating and circulation are started after feeding the material into the evaporator to the working liquid level. Moreover, when the radioactive waste liquid treatment system is in normal operation, the radioactive waste liquid in the evaporator also needs to be kept at the working level. In this embodiment, the liquid inlet of the separation device 12 is set at the working liquid level of the evaporator.

In some embodiments, the discharge port of the evaporator is arranged on the first circulation pipeline 13, and is located between the circulation pump 82 and the heating device 11, and a discharge pipe is connected between the residual liquid storage container 42 and the discharge port 103, the raffinate formed by evaporation and concentration in the evaporator is discharged into the raffinate storage container 42 through the discharge pipe 103 for storage, so as to facilitate subsequent processing. In addition, a discharge valve may be provided on the discharge pipe 103 for controlling the discharge speed of the evaporator.

In some embodiments, the feed port of the evaporator can also be arranged on the first circulation pipe 13 , between the circulation pump 82 and the separation device 12 , and higher than the bottom of the heating device 11 . In this embodiment, the discharge valve is used to control the discharge rate to remain constant, and at the same time, the feed rate of the radioactive waste liquid fed to the evaporator is controlled to remain constant, so that continuous feed and discharge can be maintained, so that the entire treatment system operating status remains stable.

As shown in Figure 1, the treatment system in this embodiment also includes a feeding device 41, which is connected to the feed port of the evaporator, and is used to store the radioactive waste liquid to be treated, and the feeding device 41 can be The radioactive waste liquid inside is fed into the evaporator for evaporation treatment. Specifically, a feeding pipeline 101 is connected between the feeding device 41 and the first circulation pipeline 13, and a feeding pump 81 is arranged on the feeding pipeline 101, so that the radioactive waste liquid in the feeding device 41 can pass through the feeding pipeline sequentially. 101. The first circulation pipeline 13 transports to the evaporator.

In addition, the processing system also includes a return pipeline 102. One end of the return pipeline 102 is connected to the feeding device 41, and the other end is connected to the feed pipeline 101. At least part of the radioactive waste liquid in the feed pipeline 101 can flow back to the feed supply through the return pipeline 102. device 41. In this embodiment, a return valve is provided on the return pipe 102, and the flow rate of the radioactive waste liquid in the return pipe 102 can be controlled by adjusting the return valve, thereby controlling the feed flow rate of the radioactive waste liquid fed into the evaporator, thereby The pressure fluctuation of the radioactive waste liquid in the feeding pipeline 101 is prevented, and the stable feeding of the radioactive waste liquid is ensured.

Further, the gas inlet of the vapor compression device 20 is connected to the separation device 12 , and the gas outlet behind the vapor compression device 20 is connected to the heating chamber of the heating device 11 . Among them, the radioactive waste liquid boiled after heat treatment evaporates in the separation device 12 to form secondary steam, and the secondary steam is discharged from the top of the separation device 12 to the vapor compression device 20, and the vapor compression device 20 compresses and heats up the secondary steam to form heating steam , the heating steam is transported to the heating chamber of the heating device 11 to exchange heat with the radioactive waste liquid in the liquid channel of the heating device 11 to realize the heat treatment of the radioactive waste liquid.

In this embodiment, the vapor 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 radioactive waste liquid, without setting up a special boiler The room is heated, which reduces the energy consumption during the evaporation treatment of radioactive waste liquid.

As shown in FIG. 1 , the radioactive waste liquid treatment system in this embodiment further includes a steam generating device 30 . The steam generating device 30 can generate high-temperature water vapor, and the steam generating device 30 is connected with the evaporator to provide a second heat source for heating the radioactive waste liquid in the evaporator. Wherein, the steam generating device 30 can be used as the heat source of the evaporator during the start-up process of the treatment system, and can also provide supplementary steam to the evaporator during the normal operation of the treatment system to supplement the heat loss.

Specifically, the steam generating device 30 has an accommodating chamber inside for accommodating water, and an electric heating part is disposed inside the steam generating device 30, and the electric heating part is used to heat the water in the accommodating chamber to form high-temperature steam. In this embodiment, the steam generating device 30 is connected to the heating chamber of the heating device 11 so as to provide a heat source for the heating device 11 to heat the radioactive waste liquid. The high-temperature steam generated by the steam generating device 30 enters the heating chamber of the heating device 11 to exchange heat with the radioactive waste liquid, so that the radioactive waste liquid boils. 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, and then flow back into the steam generator 30, so that the steam generator 30 The fluid level inside remains stable.

In some embodiments, the steam generated by the steam generating device 30 may be delivered to the inlet of the vapor compression device 20 , so as to prevent the vapor compression device 20 from surging. Compared with traditionally circulating the superheated steam from the outlet of the vapor compression device 20 to the inlet of the vapor compression device 20, in this embodiment, the high-temperature and high-pressure heating steam is transported to the heating device 11 for heat exchange, and then enters the steam generating device 30, The steam in the steam generating device 30 enters the vapor compression device 20 from the inlet, so that the temperature at the inlet of the vapor compression device 20 is prevented from being too high.

As shown in Figure 1, the processing system also includes a preheating device, and the evaporator is connected to the preheating device. When the radioactive waste liquid is evaporated, the preheating device is used to preheat the radioactive waste liquid and then transport it to the evaporator. In this embodiment, the preheating device includes a first preheating device 51, and the first preheating device 51 is arranged between the feeding device 41 and the evaporator, and is used for preheating the radioactive waste liquid. In this embodiment, the radioactive waste liquid is preheated in the first preheating device 51 and then sent to the evaporator. Specifically, the first preheating device 51 may be a heat exchanger, and the first preheating device 51 is also connected to the steam generating device 30 , and the steam generating device 30 is used to provide a heat source for the first preheating device 51 .

In this embodiment, the radioactive waste liquid is transported to the tube side of the first preheating device 51, and the hot water formed by heating by the electric heating part in the steam generator 30 is transported to the first preheating device 51 to be heated with the radioactive waste liquid. Heat exchange, so as to preheat the radioactive waste liquid at room temperature, reduce the temperature difference between the radioactive waste liquid and the phase transition temperature, and improve the efficiency of radioactive waste liquid treatment.

In addition, the processing system in this embodiment may also include a condensate storage container 43, which is connected to the first preheating device 51, and is used to receive and store the condensate in the first preheating device 51 that has been cooled after exchanging heat with the radioactive waste liquid. liquid. In some embodiments, the treatment system may not be provided with the condensate storage container 43 , and the condensate formed after heat exchange in the first preheating device 51 may be directly discharged.

In some embodiments, the condensate discharge pipe of the first preheating device 51 is also provided with a cooling device. When the temperature of the condensate flowing out of the first preheating device 51 is high, the cooling device can cool the condensate, and then Then discharge. In this embodiment, the cooling device may be a heat exchanger, and the cooling water is used as a cold source of the cooling device for exchanging heat with the condensate to reduce its temperature.

In some embodiments, the preheating device further includes a second preheating device 52, and the second preheating device 52 is arranged between the first preheating device 51 and the evaporator for preheating the radioactive waste liquid again, so that The temperature of the radioactive waste liquid is raised to close to the boiling point (for example, 98° C.) before being fed into the evaporator, so as to improve the evaporation and separation efficiency of the radioactive waste liquid.

In this embodiment, the radioactive waste liquid after initial preheating is sent to the tube side of the second preheating device 52, and the steam is sent to the shell side of the second preheating device 52 to exchange heat with the radioactive waste liquid, thereby Realize the preheating of the radioactive waste liquid again, further increase the temperature of the radioactive waste liquid, and improve the treatment efficiency. The second preheating device 52 is connected with the steam generating device 30 , the steam exchanges heat with the radioactive waste liquid to form condensate, and the condensate flows into the steam generating device 30 to supplement the water level in the steam generating device 30 .

It should be noted that, in the start-up phase, the steam used for preheating in the second preheating device 52 may 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 chamber of the heating device 11. During normal operation, the steam used for preheating in the second preheating device 52 can be the heating steam generated by the vapor compression device 20, and the heating steam passes through The heating chamber of the heating device 11 is then transported to the second preheating device 52 for heat exchange with the radioactive waste liquid. In addition, during normal operation, the steam generating device 30 can also provide steam to the second preheating device 52 to compensate for the heat loss of the system.

In some embodiments, a steam trap is also provided between the second preheating device 52 and the steam generating device 30, and a steam trap (not shown) can also be provided between the heating device 11 and the steam generating device 30. The vapor-liquid separation is performed on the condensate flowing out of the second preheating device 52 and the heating device 11 to prevent the condensate from entraining gas into the steam generating device 30 and affecting the normal operation of the steam generating device 30 .

There is a large amount of non-condensable gas (for example, air) in the equipment before the operation of the treatment system, and a small amount of non-condensable gas will be produced when the radioactive waste liquid is heated during the operation of the system. In order to eliminate the non-condensable gas in the treatment system, this The treatment system in the embodiment is also provided with a non-condensable gas emission recovery device 70 . As shown in Figure 1, the non-condensable gas discharge recovery device 70 is connected to the second preheating device 52, and is used to discharge the non-condensable gas in the second preheating device 52, and recover the steam discharged from the second preheating device 52, so as to avoid Too much non-condensable gas in the second preheating device 52 affects the heat transfer efficiency.

Specifically, the non-condensable gas emission recovery device 70 is connected to the shell side of the second preheating device 52, cooling water is passed into the non-condensable gas emission recovery device 70, and the gas in the shell side of the second preheating device 52 is discharged to After the condensed gas discharge and recovery device 70 , heat exchange is performed with the cooling water in the non-condensable gas discharge and recovery device 70 . Wherein, the steam in the exhaust gas is condensed by the cooling water to form condensate, and the condensate can be discharged directly, while the non-condensable gas is directly discharged from the non-condensable gas discharge recovery device 70 . It should be noted that the non-condensable gas in the embodiment of the present application refers to a gas that cannot be condensed by cooling water, such as air.

In this embodiment, the non-condensable gas discharge recovery device 70 is also connected to the condensate storage container 43 , and the condensate formed by the condensation of steam in the non-condensable gas discharge recovery device 70 can be recovered into the condensate storage container 43 . When the condensate storage container 43 is not provided, the condensate generated in the non-condensable gas discharge recovery device 70 is directly discharged.

In addition, the non-condensable gas discharge and recovery device 70 in this embodiment can also be connected with the heating device 11 to discharge the non-condensable gas in the heating chamber of the heating device 11 and recover the steam discharged from the heating device 11 to avoid Too much non-condensable gas will affect the heat transfer efficiency.

In some embodiments, the heating device 11 is provided with at least two exhaust ports. One of the exhaust ports is connected to 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 therein can exchange heat with the radioactive waste liquid in the second preheating device 52 The other exhaust port is connected with the non-condensable gas discharge and recovery device 70 for directly discharging the gas in the heating device 11 to the non-condensable gas discharge and recovery device 70 to directly discharge the non-condensable gas in the heating device 11 .

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

Similarly, at least two exhaust ports are provided on the second preheating device 52, and at least two exhaust ports are arranged at different heights of the second preheating device 52, and are respectively connected with exhaust valves, so that the second preheating device The gases at various locations within the thermal unit 52 are vented, thereby purging the non-condensable gases.

It should be noted that the treatment system in this 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 condensate flowing out of the first preheating device 51, but also cool the non-condensable In addition, the cooling water can also provide cooling for the oil tank and motor of the vapor compression device 20, the circulation pump 82, and the mechanical seals of other pumps in the treatment system.

As shown in Figure 2, in some embodiments, a first demister 121 is provided in the separation device 12 to remove the radioactive waste liquid carried in the secondary steam generated by the evaporation of the radioactive waste liquid, so as to prevent the secondary steam from carrying liquid Droplets enter the vapor compression device and contaminate it. Specifically, the first demister 121 may be arranged on the top of the separation device 12, above the working liquid level of the evaporator.

In some embodiments, the first demister 121 includes a wave plate demister 1211, and the wave plate demister 1211 includes a plurality of corrugated plates arranged along the axial direction of the separation device 12, with gaps between the plurality of corrugated plates . When the secondary steam formed by the evaporation of radioactive waste flows through the wave plate demister 1211, the secondary steam can flow out from the gaps between multiple wave plates, and the liquid droplets carried in the secondary steam pass through the turning of the wave plate When it collides with the corrugated plate and is attached to the surface of the corrugated plate, it can defoam the secondary steam and realize the primary purification of the secondary steam.

In some embodiments, the first demister 121 includes a wire mesh demister 1212, the wire mesh demister 1212 is made of wire mesh, and the secondary vapor formed by the evaporation of the radioactive waste liquid flows through the wire mesh demister 1212 At this time, the liquid droplets carried by the secondary steam are attached to the metal wire due to resistance, so as to separate the liquid droplets and realize the primary purification of the secondary steam.

Optionally, one of the wave plate demister 1211 and the wire mesh demister 1212 may be selected to be installed in the separation device 12 . The wave plate demister 1211 and the wire mesh demister 1212 can also be set in the separation device 12 at the same time, and the wire mesh demister 1212 can be arranged under the wave plate demister 1211, and two kinds of demisters are used for the secondary demister. Purging with steam can greatly increase the defoaming effect.

As shown in FIG. 1 , the processing system in this embodiment further includes a purification device 60 . The purification device 60 is connected between the separation device 12 and the vapor compression device 20, and is used to purify the secondary steam formed by the evaporation of the radioactive waste liquid in the separation device 12, remove the radioactive substances contained in the secondary steam, and then transport it to the steam The compression device 20 prevents radioactive contamination of the vapor compression device 20 and the downstream steam generation device 30 by the radioactive substances contained in the secondary steam.

Specifically, as shown in Figure 3, a second demister 61 is provided in the purification device 60, which is used to perform defoaming treatment on the secondary steam entering the purification device 60, and remove the radioactive waste liquid mixed in the secondary steam to realize Purification of secondary steam. In some embodiments, the second demister 61 may be a wire mesh demister, and the liquid droplets entrained by the secondary steam may adhere to the wire mesh demister, thereby reducing the liquid foam entrained by the secondary steam.

As shown in Figures 1 and 3, the top of the purification device 60 is also provided with a shower 62, and the shower 62 is sprayed in the purification device 60 for cleaning the secondary steam entering the purification device 60, so that the secondary The radioactive droplets entrained in the steam flow down with the spray liquid, thereby removing the radioactive substances contained in the secondary steam and achieving the purpose of purifying the secondary steam.

In some embodiments, the sprayer 62 is arranged above the second demister 61, and the sprayer 62 can also spray and clean the second demister 61 while spraying and cleaning the secondary steam, so that The radioactive droplets attached in the second demister 61 flow to the bottom of the purification device 60 along with the spray liquid. In addition, the spraying radiation angle of the spraying member 62 may not be less than 90 degrees, so that the spraying can radiate around to cover the entire interior of the purification device 60 , so as to realize the spray cleaning of the entire demister and the inner surface of the purification device 60 .

Further, the bottom of the purification device 60 contains a spray liquid, and the spray member 62 is connected with the liquid outlet at the bottom of the purification device 60 by a spray liquid pump 84. The shower liquid is delivered to the sprayer 62 so that the sprayer 62 can recycle the spray liquid contained in the purification device 60 to spray the secondary steam, which can not only ensure the purification effect, but also realize the recycling of the spray liquid.

As shown in Figure 1, the purification device 60 is connected to the steam generating device, and the condensate in the steam generating device can be transported to the purification device 60 as a spray liquid. While ensuring the purification effect, it also avoids setting up a special water storage tank Or water source to realize spray cleaning, which simplifies the treatment system.

In addition, when the concentration of radioactive substances in the spray liquid contained in the purification device 60 reaches a predetermined concentration threshold, a new spray liquid needs to be replaced 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 supply device 41 for radioactive waste liquid, so as to facilitate the evaporation treatment of the radioactive spray liquid. Then, the condensate in the evaporation generating device 30 is sent to the purification device 60 to supplement the spray liquid used for spray cleaning.

As shown in FIG. 1 and FIG. 3 , a packing layer 63 is further arranged in the purification device 60 , and the packing layer 63 is arranged below the second demister 61 and above the liquid level of the spray liquid. The secondary steam entering the purification device 60 passes through the packing layer 63 first, and the packing layer 63 can enhance the contact and mass transfer between the secondary steam and the spray liquid, and improve the purification efficiency. Exemplarily, the packing layer 63 includes two fixed sieve plates and packing disposed between the fixed sieve plates, so that the packing is fixed in the purification device 60 . Optionally, the packing in this embodiment can be a Pall ring packing. Because of the opening of the ring wall, the utilization rate of the inner space of the ring and the inner surface of the ring is greatly improved, the air flow resistance is small, the liquid is evenly distributed, and the flux is large. , small resistance, high separation efficiency and so on.

In this embodiment, the air inlet of the purification device 60 is arranged below the packing layer 63, so that after the secondary steam enters the purification device 60, it flows through the packing layer 63, the second demister 61 and the shower 62 in sequence, and passes through The combined effect of filler, demister and spray cleaning improves the purification effect of secondary steam. In addition, the liquid level of the spray liquid contained in the purification device 60 may be higher than the air inlet, so that the secondary steam flows upward after being cleaned by the spray liquid, further improving the purification effect.

As shown in FIG. 1 , the treatment system in this embodiment further includes a condensate pump 83 , the inlet of which is connected to the steam generator 30 , and is used to deliver hot water heated to a certain temperature in the steam generator 30 . Specifically, the outlet of the condensate pump 83 can be connected to the first preheating device 51, and is used to transport the hot water in the steam generating device 30 to the shell side of the first preheating device 51, so as to pre-heat the radioactive waste liquid. hot. The outlet of the condensate pump 83 can also be connected to the purification device 60 for replenishing the purification device 60 with spray liquid for spray cleaning.

In addition, the outlet pipe 104 of the vapor compression device 20 is provided with a spray point, and the outlet of the condensate pump 83 can also be connected to the spray point for spraying the superheated steam in the outlet pipe 104 of the vapor compression device 20 The temperature is lowered, thereby reducing the temperature of the superheated steam and converting it into saturated steam, which is conveniently provided to the heating device 11 and the second preheating device 52 as a heat source.

As shown in Figure 1, the treatment system in this embodiment also includes a sampling device 90, which is connected to the gas path before the steam inlet of the vapor compression device 20, and is used to sample the secondary vapor generated by the evaporation of the radioactive waste liquid , to facilitate the detection of secondary steam to judge the purification ability of the treatment system.

As shown in FIG. 4 , 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. It is used to provide a channel for the flow of the secondary steam to sample the secondary steam. The secondary steam in the sample flow channel 92 can be condensed by the coolant to form a liquid sample, and the concentration of the liquid sample can be detected to determine the treatment. The purification factor of the system.

In some embodiments, the sampling device 90 is provided with at least one collection port 93 connected to the sample flow channel 92 for collecting the liquid sample formed after the secondary vapor condenses in the sample flow channel 92 .

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 to the first sample port, and is used for analyzing Sampling the secondary steam that undergoes defoaming treatment; the second sample channel is connected to the second sample port for sampling the secondary steam that has been subjected to defoaming treatment after flowing through the first demister 121 in the separation device 12 . In this embodiment, by sampling and testing the secondary steam before and after the first demister 121 , the purification capability of the evaporator can be judged according to the concentration of the secondary steam.

Further, the sample flow channel 92 also includes a third sample flow channel, which is connected to the outlet of the purification device 60 to sample the secondary steam at the outlet of the purification device 60 . In this embodiment, the purification coefficient of the treatment system can be verified by detecting the concentration of the condensate in the condensate storage container. At the same time, this embodiment detects the secondary steam at the outlet of the purification device 60 by sampling, and can assist in verifying the purification coefficient and decontamination factor of the treatment system according to the concentration of the secondary steam, and judge whether the condensate storage container or its sampling port is polluted. .

The radioactive waste liquid can be evaporated and concentrated by using the treatment system in this embodiment, thereby reducing the volume of the radioactive waste liquid, so as to facilitate the later storage and solidification treatment of the radioactive waste liquid. In addition, an embodiment of the present invention also provides a radioactive waste liquid treatment method, which can be implemented by using the treatment system in any of the above-mentioned implementation manners. The processing method in this embodiment specifically includes the following steps.

Step S10, continuously feed the radioactive waste liquid 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 the radioactive waste liquid boil, and the boiling The radioactive waste liquid undergoes gas-liquid separation in the separation device 12 to generate secondary steam to concentrate the radioactive waste liquid.

Step S20, introducing the secondary steam generated by the evaporation of the radioactive waste liquid into the vapor compression device 20, using the vapor compression device 20 to compress and heat up the secondary steam, and then transporting it to the heating device 11 as the first heat source of the heating device 11, and the radioactive The waste liquid is exchanged for heat.

Step S30, continuously discharge the concentrated radioactive waste liquid in the evaporator, and control the discharge flow rate of the concentrated radioactive waste liquid, so as to ensure that the radioactive waste liquid is concentrated to a predetermined multiple.

In this embodiment, the vapor compression device 20 is used to compress and heat up the steam generated by the evaporation of the radioactive waste liquid to form heating steam, and the heating steam is used as the heat source of the evaporator, so as to recycle the latent heat of evaporation of the radioactive waste liquid, which is beneficial to reduce energy consumption. consumption. The steam generating device 30 is only used as a heat source for the evaporator during startup, and provides a small amount of compensating steam for the treatment system during normal operation to compensate heat loss of the treatment system and maintain stable operation of the system.

In addition, by adopting the treatment method in this embodiment, the discharged radioactive waste liquid can be maintained at a required concentration multiple by controlling the discharge flow rate, thereby achieving effective concentration of the radioactive waste liquid.

Specifically, the feed flow rate of the radioactive waste liquid can be controlled to maintain a predetermined feed amount, while the discharge flow rate of the radioactive waste liquid can be controlled to maintain a predetermined discharge amount, so as to ensure that the continuously discharged radioactive waste liquid has been concentrated by a predetermined multiple. In this embodiment, by simultaneously controlling the feed flow rate and the discharge flow rate of the radioactive waste liquid, for example, the feed flow rate and the discharge flow rate can be controlled to remain constant, so that the liquid level in the evaporator is maintained within the working liquid level range (for example, - 50～+50mm), and then it can ensure that the discharged radioactive waste liquid has reached the predetermined concentration ratio.

As shown in Figure 1, the evaporator in this embodiment is provided with a drain pipe 103, and a drain valve is arranged on the drain pipe 103, and the discharge flow rate of the concentrated radioactive waste liquid can be controlled by adjusting the opening of the drain valve .

Optionally, the radioactive waste liquid circulates naturally between the heating device 11 and the separation device 12 depending on the density difference caused by the temperature change.

Optionally, a circulation pump 82 is provided on the circulation pipeline between the heating device 11 and the separation device 12, and the circulation pump 82 drives the radioactive waste liquid to circulate between the heating device 11 and the separation device 12, thereby improving the treatment efficiency of the evaporator. Wherein, after the radioactive waste liquid enters the evaporator, the circulating pump 82 drives the flow and circulation of the radioactive waste liquid to increase the flow speed of the radioactive waste liquid. The radioactive waste liquid is heated to boiling in the heating device 11 , and the gas-liquid separation is carried out in the separation device 12 .

In some embodiments, the radioactive waste liquid in the feeding device 41 can be continuously fed to the evaporator. During the feeding process, the flow rate of the radioactive waste liquid in the return pipeline 102 can be adjusted to control the feeding into the heating device 11 The feeding flow rate of the radioactive waste liquid can avoid excessive pressure fluctuation in the feeding pipeline 101.

In some embodiments, the steam generated by the steam generating device 30 can also be used as the second heat source of the heating device 11 to compensate for the steam required for heating the heating device 11, and to provide heating for the heating device 11 when the radioactive waste liquid treatment system is started. heat source. The steam generating device 30 is the start-up heat source of the entire system. When the system is started, the steam generating device 30 operates at full power. After a large amount of secondary steam is generated in the evaporator and the vapor compression device 20 operates normally, the steam generating device 30 switches to low power operation. , to provide compensation steam for the system to maintain stable operation of the system.

In some embodiments, the radioactive waste liquid in the feeding device 41 can be continuously transported to the first preheating device 51, and at the same time, the condensate in the steam generating device 30 is transported to the first preheating device 51, so as to prevent radioactive The waste liquid is preheated, and then the preheated radioactive waste liquid is fed to the evaporator.

Further, the radioactive waste liquid preheated by the first preheating device 51 can be sent to the second preheating device 52, and the heated steam generated by the vapor compression device 20 can be sent to the heating device 11, and then sent to the second preheating device 52. The heat device 52 is used as the heat source of the second preheating device 52 to perform secondary preheating on the radioactive waste liquid, and the radioactive waste liquid after the secondary preheating is fed to the evaporator.

In this embodiment, the radioactive waste liquid enters the first preheating device 51 through the feed pump 81, and the radioactive waste liquid is preheated to 70°C with the condensate of the secondary steam produced after heating the radioactive waste liquid from the steam generating device 30. After about ℃, it is sent to the second preheating device 52. In the second preheating device 52 , the radioactive waste liquid is further preheated to above 90° C. by using the heating steam generated after the secondary steam in the heating device 11 is compressed.

Among them, the secondary steam is pressurized and heated by the vapor compression device 20, and then sent into the heating chamber of the heating device 11 as heating steam, and a part of it enters the shell side of the second preheating device 52 as an evaporator and a second preheating device. The heat source of 52 completes the evaporation and preheating process of the radioactive waste liquid respectively, and the secondary vapor newly generated by the evaporation of the radioactive waste liquid enters the vapor compression device 20 to be heated and pressurized, and is used as a heat source to heat the subsequent radioactive waste liquid, forming a continuous cycle process .

In some embodiments, the condensate in the heating device 11 and the second preheating device 52 flows into the steam generating device 30 by gravity to replenish the condensate for the steam generating device 30 , and the condensate is used for the heating device 11 and the second preheating device 52 . The steam in the device 52 is condensed after exchanging heat with the radioactive waste liquid.

Specifically, the compressed and heated secondary steam heats the radioactive waste liquid and condenses into a condensate at about 112°C, which flows into the steam generating device 30 by gravity, and most of the condensate is transported to the first preheating device 51 by the condensate pump 83 The radioactive waste liquid at room temperature can be preheated internally, and the radioactive waste liquid at room temperature can be preheated to about 70° C., and the condensate is cooled and sent to the condensate storage container 43 as a purified liquid.

Further, steam traps can be used to separate vapor and liquid from the condensate flowing out of the heating device 11 and/or the second preheating device 52 , so as to prevent the gas contained in the condensate from entering the steam generating device 30 .

In some embodiments, before the steam in the separation device 12 leaves the separation device 12 , the first demister 121 is used to demister the steam. In addition, the secondary steam separated by the separation device 12 can also be purified by the purification device 60 , and the secondary steam purified by the purification device 60 can be sent to the vapor compression device 20 .

Specifically, the secondary vapor generated by the evaporation of the radioactive waste liquid rises in the separation device 12 and first passes through the first demister 121 for defoaming, then passes through the purification device 60, passes through the packing layer 63, the second demister 61 and the spray Purify further. The secondary steam coming out of the purification device 60 directly enters the vapor compression device 20 for compression.

In addition, the condensate pump 83 can send a part of the condensate at about 112°C in the steam generator 30 to the outlet pipe 104 of the vapor compression device 20 to eliminate the superheat of the pressurized and heated secondary steam. The outlet of the compression device 20 is vaporized, the temperature of the secondary steam is lowered, and it becomes saturated steam and enters the heating device 11 to heat the radioactive waste liquid. There is also a small amount of condensed liquid sent into the purification device 60 to be used as a spray liquid. During operation, the spray liquid pump 84 circulates and sprays the secondary steam in the purification device 60 to ensure the purification effect.

In some embodiments, the condensate storage container 43 can be used to collect the condensate flowing out of the first preheating device 51 after heat exchange with the radioactive waste liquid, and the purification coefficient of the treatment system can be verified by detecting the concentration of the collected condensate.

Further, a cooling device is provided between the condensate storage container 43 and the first preheating device 51 , and the cooling device cools the condensate flowing out of the first preheating device 51 before collecting it into the condensate storage container 43 .

In addition, there is a large amount of non-condensable gas in the equipment before the operation of the system, and a small amount of non-condensable gas will be produced when the radioactive waste liquid is heated during the operation of the system. Each has at least one exhaust port, and each exhaust port is connected with an exhaust valve. During the operation of the system, the exhaust valve is opened regularly to discharge the non-condensable gas in the system and improve the heat exchange efficiency of the equipment.

In some embodiments, the working current of the vapor compression device 20 can also be monitored to avoid abnormalities of the vapor compression device 20 . Wherein, when the operating current of the vapor compression device 20 drops, it indicates that the vapor compression device 20 is in surge. At this time, the regulating valve of the outlet pipeline 104 of the steam generating device 30 can be controlled to supply air to the inlet of the vapor compression device 20, Prevent surge.

Regarding the embodiments of the present invention, it should also be noted that, under the condition of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and the protection scope of the present invention should be based on the protection scope of the claims.

Claims (20)

1. A radioactive waste treatment method, characterized in that, comprising: Continuously feeding the radioactive waste liquid into the evaporator, the evaporator includes a heating device and a separation device, and the radioactive waste liquid circulates between the heating device and the separation device; heating the waste liquid to make the radioactive waste liquid boil, and the boiled radioactive waste liquid is separated into vapor and liquid in the separation device to generate secondary steam to concentrate the radioactive waste liquid; The secondary steam generated by the evaporation of the radioactive waste liquid is introduced into the vapor compression device, and the secondary steam is compressed and heated by the vapor compression device, and then sent to the heating device as the first heat source of the heating device, and The radioactive waste liquid is subjected to heat exchange; The concentrated radioactive waste liquid in the evaporator is continuously discharged, and the discharge flow rate of the concentrated radioactive waste liquid is controlled to ensure that the radioactive waste liquid is concentrated to a predetermined multiple. 2. The method according to claim 1, characterized in that the radioactive waste liquid circulates naturally between the heating device and the separation device depending on the density difference caused by the temperature change; or A circulation pump is arranged on the circulation pipeline between the heating device and the separation device, and the circulation pump drives the radioactive waste liquid to circulate between the heating device and the separation device. 3. The method according to claim 1, further comprising: Continuously feed the radioactive waste liquid in the feeding device to the evaporator; wherein, a feeding pipeline is connected between the feeding device and the evaporator, and the feeding pipeline is connected with the A return pipeline connected to the feeding device, the return pipeline is used to return at least part of the radioactive waste liquid in the feeding pipeline to the feeding device; The flow rate of the radioactive waste liquid in the return pipeline is adjusted to control the feed flow rate of the radioactive waste liquid fed into the heating device. 4. The method according to claim 1, further comprising: using the steam generated by the steam generating device as the second heat source of the heating device, so as to compensate for the steam required for heating by the heating device, and Provide heat source for the heating device when the radioactive waste liquid treatment system is started. 5. The method according to claim 4, wherein the continuous feeding of the radioactive waste liquid to the evaporator comprises: Continuously transport the radioactive waste liquid in the feeding device to the first preheating device; transporting the condensate in the steam generating device to the first preheating device to preheat the radioactive waste liquid; The preheated radioactive waste liquid is fed to the evaporator. 6. The method according to claim 5, wherein the continuous feeding of the radioactive waste liquid to the evaporator further comprises; Transporting the radioactive waste liquid preheated by the first preheating device to the second preheating device; The heated steam generated by the vapor compression device is sent to the heating device, and then sent to the second preheating device as a heat source for the second preheating device to perform secondary preheating on the radioactive waste liquid ; The radioactive waste liquid after secondary preheating is fed to the evaporator. 7. The method according to claim 6, further comprising: flowing the condensate in the heating device and the second preheating device into the steam generating device by gravity to replenish the steam generating device Condensate, the condensate is formed by condensation after heat exchange between the steam in the heating device and the second preheating device and the radioactive waste liquid. 8. The method according to claim 7, characterized in that a steam trap is arranged between the heating device and the steam generating device, and/or between the second preheating device and the steam generating device A steam trap is provided; the method also includes: The steam trap is used to conduct vapor-liquid separation of the condensate flowing out of the heating device and/or the second preheating device, so as to prevent the gas entrained in the condensate from entering the steam generating device. 9. The method according to claim 1, wherein a first demister is provided in the separation device, and the method further comprises: Before the steam in the separation device leaves the separation device, the steam is defoamed by the first demister. 10. The method according to claim 1, characterized in that, a purification device is arranged between the separation device and the vapor compression device; the method also includes: Purify the secondary steam separated by the separation device by using the purification device; The secondary steam purified by the purification device is sent to the vapor compression device. 11. The method according to claim 6, further comprising: using a condensate storage container to collect the condensate flowing out of the first preheating device after heat exchange with the radioactive waste liquid. 12. The method according to claim 11, wherein a cooling device is also provided between the condensate storage container and the first preheating device, and the method further comprises: the cooling device After the condensate flowing out of the first preheating device is cooled, it is collected into the condensate storage container. 13. A radioactive waste liquid treatment system, characterized in that it is used to realize the radioactive waste liquid treatment method according to any one of claims 1-12, comprising: The evaporator is used to evaporate and concentrate the radioactive waste liquid; the evaporator includes: A heating device, the heating device is formed with a heating chamber for providing a flow channel for the heating steam, the heating chamber is provided with a liquid flow channel for the flow of the radioactive waste liquid, and the heating steam can be exchanged with the radioactive waste liquid heat, to heat-treat the radioactive waste liquid; A separation device, the separation device is connected with the liquid channel of the heating device, and is used for separating the vapor and liquid of the boiled radioactive waste liquid after the heat treatment to form secondary steam, so as to concentrate the radioactive waste liquid; A circulation pipeline, the circulation pipeline is respectively connected with the separation device and the heating device, and is used to provide channels for the radioactive waste liquid to circulate between the heating device and the separation device; a vapor compression device, arranged between the separation device and the inlet of the heating chamber, the vapor compression device is used to compress the secondary vapor to raise the temperature, and serve as the first heat source of the heating device; The raffinate storage container is connected with the heating device and is used to receive and store the raffinate formed by concentrating the radioactive waste liquid after evaporation; Wherein, a liquid discharge valve is arranged between the raffinate storage container and the heating device for controlling the discharge flow rate of the raffinate. 14. The system of claim 13, further comprising: A circulation pump, arranged on the circulation pipeline, is used to drive the radioactive waste liquid to circulate between the separation device and the heating device. 15. The system of claim 13, further comprising: A feeding device, connected to the evaporator, used to store the radioactive waste liquid to be treated; feed pipeline, connected between the feeding device and the circulation pipeline; A return pipeline, one end is connected to the feeding device, and the other end is connected to the feeding pipeline, and the returning pipeline is used to provide a channel for at least part of the radioactive waste liquid in the feeding pipeline to flow back to the feeding device ; Wherein, the return pipeline is provided with a return valve for controlling the flow of radioactive waste liquid in the return pipeline. 16. The system of claim 15, further comprising: a steam generating device, the steam generating device contains water, the steam generating device is configured to heat the water to generate steam, the steam generating device is connected with the heating device, and is used to provide the heating device with second heat source. 17. The system of claim 16, further comprising: The first preheating device is arranged between the feeding device and the evaporator, the first preheating device is connected with the steam generating device, and the steam generating device is used for preheating the first The device provides condensate to preheat the radioactive waste liquid; The second preheating device is arranged between the first preheating device and the evaporator, the second preheating device communicates with the heating chamber of the heating device, and the heating device is used for the The second preheating device provides heating steam for secondary preheating of the radioactive waste liquid. 18. The system according to claim 17, characterized in that, a steam trap is arranged between the heating device and the steam generating device, and the steam trap is used to block the heat generated by the heating steam in the heating device after heat exchange. gas entrained in the condensate enters said steam generating device; and/or, A steam trap is arranged between the second preheating device and the steam generating device, and the steam trap is used to prevent the gas entrained in the condensate formed after the heat exchange of the heating steam in the second preheating device from entering the Steam generating device. 19. The system of claim 17, further comprising: A condensate storage container, connected to the first preheating device, for receiving and storing the condensate in the first preheating device after exchanging heat with the radioactive waste liquid; A cooling device, arranged between the condensate storage container and the first preheating device, is used for cooling the condensate. 20. The system according to claim 13, characterized in that a purification device is provided between the separation device and the vapor compression device for purifying the secondary steam.

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