Waste liquid purification treatment device and low-level radioactive waste liquid purification treatment system

Abstract

According to the waste liquid purification treatment device and the low-level radioactive waste liquid purification treatment system, reverse osmosis membranes with different operation pressures can be selected according to different concentrations of low-level radioactive waste liquid, so that the energy consumption in the concentration process and the use consumption of the reverse osmosis membranes are reduced, and the overall energy consumption and the operation cost of the waste liquid purification treatment device are reduced. The waste liquid purification treatment device comprises a pretreatment assembly and a membrane filtration assembly. The pretreatment assembly is used for filtering the low-level radioactive waste liquid flowing into the water tank to remove solid particles in the low-level radioactive waste liquid so as to form filtered waste liquid, and conveying the filtered waste liquid to the membrane filtration assembly; the membrane filtration assembly comprises a first reverse osmosis membrane and a second reverse osmosis membrane which are connected in parallel, and the operation pressure of the first reverse osmosis membrane is smaller than that of the second reverse osmosis membrane; a water inlet of the first reverse osmosis membrane and a water inlet of the second reverse osmosis membrane are communicated with an outlet of the pretreatment assembly and are used for respectively obtaining low-level concentrated solutions with different concentrations of filtered waste liquid so as to separate out pure water.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste liquid treatment, and particularly relates to a waste liquid purification treatment device and a low-level radioactive waste liquid purification treatment system. Background Art

[0002] With the continuous development of the chemical industry, more and more chemical plants have sprung up. These chemical plants usually generate toxic and harmful waste liquids during the production process, and some even contain substances with low radioactivity (radioactivity less than 10e-6 Bq / L). If these low-level radioactive waste liquids are directly discharged, they will undoubtedly have extremely bad effects on the environment and people. Therefore, under the pressure of environmental protection, chemical plants have to use supporting purification devices to purify these wastes.

[0003] Currently, the treatment methods for low-level radioactive waste liquids include using resins to adsorb radioactive particles and natural evaporation and concentration. Using resins to adsorb radioactive particles requires consuming a large amount of resins, so the cost is relatively high. While using the method of natural evaporation and concentration requires using a large-area evaporation pond, the floor area of the evaporation pond is large, and natural evaporation takes a long time.

[0004] In the prior art, there is also a method of concentrating low-level radioactive waste liquid using a reverse osmosis membrane. During the use of the reverse osmosis membrane, in order to ensure the concentration effect, the operating pressure of the reverse osmosis membrane is usually set relatively high (usually about 180 bar). This requires providing a relatively high pressure to the low-level radioactive waste liquid, increasing the energy consumption during the concentration process of the low-level radioactive waste liquid. And when the operating pressure of the reverse osmosis membrane is set relatively high, the service life of the reverse osmosis membrane will be greatly reduced, and the replacement cycle becomes shorter, thereby increasing the operating cost during the concentration process of the low-level radioactive waste liquid. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a waste liquid purification treatment device and a low-level radioactive waste liquid purification treatment system in view of the above deficiencies in the prior art, which can select reverse osmosis membranes with different operating pressures according to the different concentrations of low-level radioactive waste liquids, thereby reducing the energy consumption and the consumption of the reverse osmosis membrane during the concentration process, and further reducing the overall energy consumption and operating cost of the waste liquid purification treatment device.

[0006] In a first aspect, an embodiment of the present invention provides a waste liquid purification and treatment device, which includes a pretreatment component and a membrane filtration component. The pretreatment component is used to filter the low-level radioactive waste liquid flowing into the water tank to remove solid particles in the low-level radioactive waste liquid, form filtered waste liquid, and transport the filtered waste liquid to the membrane filtration component. The membrane filtration component includes a first reverse osmosis membrane and a second reverse osmosis membrane connected in parallel. The operating pressure of the first reverse osmosis membrane is less than that of the second reverse osmosis membrane; the water inlets of the first reverse osmosis membrane and the second reverse osmosis membrane are both connected to the outlet of the pretreatment component, and are used to obtain low-level radioactive concentrates with different concentrations of the filtered waste liquid respectively to separate pure water.

[0007] In some embodiments, both the first reverse osmosis membrane and the second reverse osmosis membrane are disk tube reverse osmosis membranes. The operating pressure of the first reverse osmosis membrane is P1, 60 bar ≤ P1 ≤ 80 bar, and the operating pressure of the second reverse osmosis membrane is P2, 150 bar ≤ P2 ≤ 170 bar.

[0008] In some embodiments, the membrane filtration component further includes a booster pump. The inlet of the booster pump is connected to the outlet of the pretreatment component, and the outlet of the booster pump is respectively connected to the water inlets of the first reverse osmosis membrane and the second reverse osmosis membrane.

[0009] In some embodiments, the membrane filtration component further includes a first pressure transmitter, a second pressure transmitter, and a controller. The first pressure transmitter is arranged at the inlet of the booster pump and is used to detect the pressure at the inlet of the booster pump. The second pressure transmitter is arranged at the outlet of the booster pump and is used to detect the pressure at the outlet of the booster pump. The controller is electrically connected to the first pressure transmitter, the second pressure transmitter, and the booster pump respectively, and is used to control the start and stop of the booster pump according to the pressure at the inlet of the booster pump and the pressure at the outlet of the booster pump.

[0010] In some embodiments, the waste liquid purification and treatment device further includes a raw water tank and a concentrated water tank. The raw water tank is connected to the inlet of the pretreatment component and is used to receive low-level radioactive waste liquid. The inlet of the concentrated water tank is respectively connected to the concentrated water outlets of the first reverse osmosis membrane and the second reverse osmosis membrane, and the outlet of the concentrated water tank is connected to the raw water tank. After collecting the low-level radioactive concentrate, the low-level radioactive concentrate is transported back into the raw water tank.

[0011] In some embodiments, a circulation pump is arranged between the outlet of the concentrated water tank and the raw water tank.

[0012] In some embodiments, the pure water outlets of the first reverse osmosis membrane and the second reverse osmosis membrane are both connected to the raw water tank, and are used to transport the pure water separated from the filtered waste liquid after passing through the first reverse osmosis membrane and the second reverse osmosis membrane into the raw water tank.

[0013] In some embodiments, the waste liquid purification treatment device further includes a chiller. The chiller is connected to the raw water tank and is used to cool the low-level radioactive waste liquid in the raw water tank.

[0014] In some embodiments, the pretreatment component includes a feed pump and a security filter. The inlet of the feed pump is connected to the raw water tank. The inlet of the security filter is connected to the outlet of the feed pump, and its outlet is connected to the inlet of the booster pump, and is used to filter the solid particles in the low-level radioactive waste liquid to generate filtered waste liquid.

[0015] In some embodiments, the filtration accuracy of the security filter is a, and 3μm ≤ a ≤ 5μm.

[0016] Thus, the waste liquid purification treatment device provided by the embodiment of the present invention can filter the low-level radioactive waste liquid through the pretreatment component by setting the pretreatment component to remove the solid particles in the low-level radioactive waste liquid, and can avoid the solid particles from blocking the membrane filtration component in the subsequent process and affecting the service life of the membrane filtration component. By setting the membrane filtration component and making the membrane filtration component include a first reverse osmosis membrane and a second reverse osmosis membrane connected in parallel, the filtered waste liquid can be concentrated by the first reverse osmosis membrane and the second reverse osmosis membrane respectively; further, by making the operating pressure of the first reverse osmosis membrane less than the operating pressure of the second reverse osmosis membrane, when the salt content of the filtered waste liquid is low, that is, the concentration of the filtered waste liquid is low, only a lower pressure needs to be provided to the filtered waste liquid to make the filtered waste liquid pass through the first reverse osmosis membrane alone for concentration and separate pure water, which can reduce the energy consumption when boosting the filtered waste liquid and maintain the normal service life of the first reverse osmosis membrane; when the salt content of the filtered waste liquid is high, that is, the concentration of the filtered waste liquid is high, the filtered waste liquid can be made to enter the second reverse osmosis membrane alone for concentration, which can increase the salt concentration in the finally formed concentrated waste liquid, meet the concentration requirements of the low-level radioactive waste liquid, and reduce the total amount of waste liquid to be treated finally. In summary, during the use of the waste liquid purification treatment device, the concentration requirements of the low-level radioactive waste liquid can be met through the time-sharing operation of the first reverse osmosis membrane and the second reverse osmosis membrane; and the energy consumption during the operation of the first reverse osmosis membrane is low; while the second reverse osmosis membrane only works when the salt content of the filtered waste liquid is high, which can make the service life of the second reverse osmosis membrane longer, increase the replacement cycle of the second reverse osmosis membrane, and thus can reduce the use cost of the second reverse osmosis membrane. Therefore, the overall energy consumption and operation cost of the waste liquid purification treatment device can be reduced.

[0017] Second aspect, the embodiments of the present invention further provide a low-level waste liquid purification and treatment system. The low-level waste liquid purification and treatment system includes a waste liquid tank, a waste liquid purification and treatment device, and a product water tank. The waste liquid tank is used to store low-level waste liquid and transport the low-level waste liquid to the waste liquid purification and treatment device. The waste liquid purification and treatment device is communicated with the waste liquid tank. The product water tank is communicated with the pure water outlets of the first reverse osmosis membrane and the second reverse osmosis membrane in the waste liquid purification and treatment device, and is used to store the pure water separated by the first reverse osmosis membrane and the second reverse osmosis membrane.

[0018] The low-level waste liquid purification and treatment system provided by the embodiments of the present invention has the same beneficial effects as the above-mentioned waste liquid purification and treatment device, which will not be elaborated here. Description of the Drawings

[0019] Figure 1 : is a structural diagram of a waste liquid purification and treatment device provided by an embodiment of the present invention;

[0020] Figure 2 : is Figure 1 a partial enlarged view of the Q1 area in

[0021] Figure 3 : is Figure 1 a partial enlarged view of the Q2 area in

[0022] Figure 4 : is a schematic diagram of a waste liquid purification and treatment device provided by an embodiment of the present invention.

[0023] Wherein, 1 - raw water tank; 2 - feed pump; 3 - security filter; 4 - booster pump; 5 - first reverse osmosis membrane; 6 - second reverse osmosis membrane; 7 - product water tank; 8 - concentrated water tank; 9 - chiller; 10 - circulation pump; 11 - waste liquid tank. Detailed Embodiments

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0025] Embodiment 1:

[0026] As Figure 1 shown, an embodiment of the present invention provides a waste liquid purification and treatment device, which is applied to the treatment process of low-level waste liquid and is used to concentrate the low-level waste liquid, so as to reduce the total amount of waste liquid that finally needs to be treated.

[0027] Exemplarily, the radioactivity intensity of the above-mentioned low-level waste liquid is less than 10e-6 Bq / L. The salts in the low-level waste liquid are mainly radionuclides (mainly Cs and Sr) and sodium nitrate. The initial concentration of sodium nitrate is generally less than 5 g / L, and it contains some solid particles.

[0028] Those skilled in the art can understand that the waste liquid purification treatment device can also concentrate ordinary solutions without radioactivity.

[0029] Such as Figure 1 , Figure 2 and Figure 3 shown, the waste liquid purification treatment device can be arranged in a shielding room ( Figure 1 the dashed box in), and the waste liquid purification treatment device includes a pretreatment component and a membrane filtration component. The pretreatment component is used to filter the low-level radioactive waste liquid flowing into the water tank to remove solid particles in the low-level radioactive waste liquid, form filtered waste liquid, and transport the filtered waste liquid to the membrane filtration component.

[0030] Figure 1 The arrow direction in is the flow direction of the solution.

[0031] Exemplarily, the water tank is used to store low-level radioactive waste liquid. The water tank can be, for example, the original water tank 1 described later. An immersion level gauge LT can be arranged in the original water tank 1, and different scales (such as three scales of high liquid level, medium liquid level, and low liquid level) are arranged on the immersion level gauge LT for monitoring the liquid level in the original water tank 1.

[0032] The solid particles in the low-level radioactive waste liquid can include nuclide suspensions and colloids.

[0033] Such as Figure 1 , Figure 2 , Figure 3 shown, the pretreatment component includes a feed pump 2 and a security filter 3. The inlet of the feed pump 2 is communicated with the original water tank 1. The inlet of the security filter 3 is communicated with the outlet of the feed pump 2, and its outlet is communicated with the inlet of a booster pump 4, and is used to filter solid particles in the low-level radioactive waste liquid to generate filtered waste liquid.

[0034] Exemplarily, the feed pump 2 can be a general water pump, and the water pump is made of stainless steel, and is used to transport the low-level radioactive waste liquid in the original water tank 1 to the security filter 3. A ball valve SV101 is arranged between the feed pump 2 and the original water tank 1.

[0035] Exemplarily, the security filter 3 (also called a precision filter) is an existing device, and tubular filters such as PP meltblown and activated carbon filters are arranged inside it as filtering elements, and can filter solid particles. A ball valve SV103 is arranged between the security filter 3 and the feed pump 2.

[0036] By filtering solid particles in the low-level radioactive waste liquid through the pretreatment component, it is possible to avoid blockage of the membrane filtration component in subsequent processes and affect the service life of the membrane filtration component.

[0037] Such as Figure 1 , Figure 2 , Figure 3As shown in the figure, the membrane filtration assembly includes a first reverse osmosis membrane 5 and a second reverse osmosis membrane 6 connected in parallel. The operating pressure of the first reverse osmosis membrane 5 is less than that of the second reverse osmosis membrane 6. The water inlets of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 are both connected to the outlet of the pretreatment assembly, and are used to obtain low-level radioactive concentrates with different concentrations of filtered waste liquid respectively to separate pure water.

[0038] A ball valve SV104 is provided between the security filter 3 and the membrane filtration assembly.

[0039] The reverse osmosis membrane is an artificial semi-permeable membrane with certain characteristics made by simulating biological semi-permeable membranes and is the core component of reverse osmosis technology. The principle of reverse osmosis technology is that under the action of a pressure higher than the osmotic pressure of the solution, these substances and water are separated based on the fact that other substances cannot pass through the semi-permeable membrane.

[0040] Influencing factors during the operation of the reverse osmosis membrane:

[0041] 1. The inlet pressure (operating pressure) of the reverse osmosis membrane itself does not affect the salt permeation rate. However, the increase in the inlet pressure makes the net pressure driving reverse osmosis increase, resulting in an increase in the water production rate. At the same time, the salt permeation rate remains almost unchanged. The increased water production dilutes the salt passing through the membrane, reducing the salt permeation rate and increasing the desalination rate.

[0042] 2. Osmotic pressure is a function of the salt or organic matter concentration in water. The higher the inlet salt content (concentration), the greater the concentration difference, the higher the salt permeation rate, and thus the lower the desalination rate.

[0043] In some examples, both the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 are disk tube reverse osmosis membranes (i.e., DTRO membranes).

[0044] Compared with the method of natural evaporation concentration in the prior art, the process of using disk tube reverse osmosis membranes for concentration does not require waiting for the natural evaporation of low-level radioactive waste liquid, and the time spent is shorter. Moreover, the method of natural evaporation concentration requires the construction of a large-area evaporation pond, with a higher investment cost, while the investment cost of the process of using disk tube reverse osmosis membranes for concentration is lower.

[0045] As Figure 1 、 Figure 2 、 Figure 3 As shown in the figure, the parallel connection of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 means that the filtered waste liquid can enter the first reverse osmosis membrane 5 alone through the water inlet of the first reverse osmosis membrane 5 for concentration to obtain a low-level radioactive concentrate with the first concentration and separate pure water; or the filtered waste liquid can enter the second reverse osmosis membrane 6 alone through the water inlet of the second reverse osmosis membrane 6 for concentration to obtain a low-level radioactive concentrate with the second concentration and separate pure water.

[0046] Exemplarily, the operating pressure of the first reverse osmosis membrane 5 can be 40 bar, and the operating pressure of the second reverse osmosis membrane 6 is 60 bar; alternatively, the operating pressure of the first reverse osmosis membrane 5 can be 60 bar, and the operating pressure of the second reverse osmosis membrane 6 is 80 bar; alternatively, the operating pressure of the first reverse osmosis membrane 5 can be 80 bar, and the operating pressure of the second reverse osmosis membrane 6 is 120 bar, or it can also be other pressures.

[0047] Those skilled in the art can understand that if the inlet pressure of the reverse osmosis membrane needs to be satisfied, additional pressurization of the filtered waste liquid is required, and a pressurization device (such as the booster pump 4 described below) needs to be used, so the energy consumption during pressurization of the filtered waste liquid will increase; moreover, when the inlet pressure of the reverse osmosis membrane is relatively high, the microfilter in the reverse osmosis membrane is more likely to become blocked, thus reducing the lifespan of the reverse osmosis membrane and shortening the replacement cycle.

[0048] In some embodiments, the operating pressure of the first reverse osmosis membrane 5 is P1, where 60 bar ≤ P1 ≤ 80 bar, and the operating pressure of the second reverse osmosis membrane 6 is P2, where 150 bar ≤ P2 ≤ 170 bar.

[0049] Exemplarily, the operating pressure P1 of the first reverse osmosis membrane 5 can be 60 bar, 75 bar, or 80 bar, and the operating pressure P2 of the second reverse osmosis membrane 6 can be 150 bar, 160 bar, or 170 bar.

[0050] In some examples, the operating pressure P1 of the first reverse osmosis membrane 5 is selected to be 75 bar, and the operating pressure P2 of the second reverse osmosis membrane 6 is selected to be 160 bar.

[0051] In the embodiments of the present invention, by making the operating pressure of the first reverse osmosis membrane 5 less than the operating pressure of the second reverse osmosis membrane 6, when the salt content of the filtered waste liquid is low (i.e., the concentration of the filtered waste liquid is low), the filtered waste liquid can enter the first reverse osmosis membrane 5 alone for concentration. At this time, a relatively low pressure provided to the filtered waste liquid can achieve the concentration of the filtered waste liquid and separate pure water, which can reduce the energy consumption during pressurization of the filtered waste liquid and maintain the normal service life of the first reverse osmosis membrane 5. At this time, the second reverse osmosis membrane 6 is not working, so the replacement cycle of the second reverse osmosis membrane 6 can be extended, thereby reducing the usage cost of the second reverse osmosis membrane 6.

[0052] At this time, the maximum osmotic pressure that the first reverse osmosis membrane 5 can provide is 35 bar. After testing by the inventor, the first reverse osmosis membrane 5 can concentrate sodium nitrate in the filtered waste liquid to 60 g / L. Correspondingly, the nuclide concentration in the concentrated waste liquid also increases, thereby achieving the concentration of the low-level waste liquid and reducing the total amount of radioactive waste liquid to be finally treated.

[0053] When the salt content of the filtered waste liquid is relatively high (i.e., the concentration of the filtered waste liquid is relatively high), the filtered waste liquid can enter the second reverse osmosis membrane 6 alone for concentration. At this time, a relatively high pressure needs to be provided to the filtered waste liquid, but the concentration of salts in the concentrated waste liquid can be increased to meet the final concentration requirements of the low-level waste liquid. Since the second reverse osmosis membrane 6 is only used to treat the filtered waste liquid with a relatively high salt content, the second reverse osmosis membrane 6 does not operate continuously for a long time, so the service life of the second reverse osmosis membrane 6 is relatively long, the replacement cycle is relatively long, and the usage cost of the second reverse osmosis membrane 6 can be reduced.

[0054] In this embodiment, the maximum osmotic pressure that the second reverse osmosis membrane 6 can provide is 100 bar. After testing by the inventor, the second reverse osmosis membrane 6 can concentrate sodium nitrate in the filtered waste liquid to 160 g / L. Correspondingly, the nuclide concentration in the concentrated waste liquid also increases, thereby realizing the concentration of the low-level waste liquid and reducing the amount of radioactive waste liquid to be finally treated.

[0055] Therefore, the waste liquid purification treatment device provided by the embodiment of the present invention can filter the low-level waste liquid through the pretreatment component to remove solid particles in the low-level waste liquid, and can avoid blockage of the membrane filtration component in the subsequent process by solid particles, thereby affecting the service life of the membrane filtration component. By setting the membrane filtration component and making the membrane filtration component include the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 connected in parallel, the filtered waste liquid can be concentrated by the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 respectively; further, by making the operating pressure of the first reverse osmosis membrane 5 less than the operating pressure of the second reverse osmosis membrane 6, when the salt content of the filtered waste liquid is relatively low (i.e., the concentration of the filtered waste liquid is relatively low), only a relatively low pressure needs to be provided to the filtered waste liquid to enable the filtered waste liquid to pass through the first reverse osmosis membrane 5 alone for concentration and separate pure water, which can reduce the energy consumption during pressurization of the filtered waste liquid and maintain the normal service life of the first reverse osmosis membrane 5; when the salt content of the filtered waste liquid is relatively high (i.e., the concentration of the filtered waste liquid is relatively high), the filtered waste liquid can enter the second reverse osmosis membrane 6 alone for concentration, which can increase the concentration of salts in the finally formed concentrated waste liquid, meet the concentration requirements of the low-level waste liquid, and reduce the total amount of waste liquid to be finally treated. In summary, during the use of the waste liquid purification treatment device, through the time-sharing operation of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6, the concentration requirements of the low-level waste liquid can be met; and the energy consumption during the operation of the first reverse osmosis membrane 5 is relatively low; while the second reverse osmosis membrane 6 only operates when the salt content of the filtered waste liquid is relatively high, which can make the service life of the second reverse osmosis membrane 6 relatively long, increase the replacement cycle of the second reverse osmosis membrane 6, and thus reduce the usage cost of the second reverse osmosis membrane 6. Therefore, the overall energy consumption and operating cost of the waste liquid purification treatment device can be reduced.

[0056] In some embodiments, such as Figure 1 、 Figure 2 、Figure 3 As shown, the membrane filtration assembly further includes a booster pump 4. The inlet of the booster pump 4 is communicated with the outlet of the pretreatment assembly, and the outlet of the booster pump 4 is respectively communicated with the water inlet of the first reverse osmosis membrane 5 and the water inlet of the second reverse osmosis membrane 6.

[0057] Exemplarily, the booster pump 4 can be an existing electric booster pump. The pressure output by the booster pump 4 is adjustable.

[0058] For example, when the first reverse osmosis membrane 5 needs to work, the pressure output by the booster pump 4 is 75 bar; when the second reverse osmosis membrane 6 needs to work, the pressure output by the booster pump 4 is 160 bar.

[0059] As Figure 1 , Figure 2 , Figure 3 As shown, a ball valve SV104 is provided between the security filter 3 and the booster pump 4. A ball valve SV106 is provided between the booster pump 4 and the water inlet of the first reverse osmosis membrane 5, and a ball valve SV105 is provided between the booster pump 4 and the water inlet of the second reverse osmosis membrane 6.

[0060] By providing the booster pump 4, the filtered waste liquid can enter the water inlets of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 with a relatively high pressure to meet the normal operating conditions of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6.

[0061] As Figure 1 , Figure 2 , Figure 3 As shown, the membrane filtration assembly further includes a first pressure transmitter, a second pressure transmitter and a controller. The first pressure transmitter is provided at the inlet of the booster pump 4 for detecting the pressure at the inlet of the booster pump 4. The second pressure transmitter is provided at the outlet of the booster pump 4 for detecting the pressure at the outlet of the booster pump 4. The controller is electrically connected to the first pressure transmitter, the second pressure transmitter and the booster pump 4 respectively, and is used to control the start and stop of the booster pump 4 according to the pressure at the inlet of the booster pump 4 and the pressure at the outlet of the booster pump 4.

[0062] Figure 1 , Figure 2 The "PT" in Figure 1 shows the installation positions of the first pressure transmitter and the second pressure transmitter. The controller is not shown in

[0063] Exemplarily, the controller can be a general programmable logic controller, such as a programmable logic controller of model S7-300 produced by Siemens Corporation.

[0064] Exemplarily, when the water inlet pressure of the boost pump 4 is lower than the first set value (e.g., 10 bar), the controller controls the boost pump 4 to stop working, thereby preventing the boost pump 4 from being evacuated and damaged; when the water outlet pressure of the boost pump 4 is continuously higher than the second set value (e.g., 200 bar), the controller controls the boost pump 4 to stop working, thereby protecting the second reverse osmosis membrane 6 from being damaged.

[0065] For those skilled in the art, the controller controls the start and stop of the boost pump 4 according to the pressure at the inlet of the boost pump 4 and the pressure at the outlet of the boost pump 4, which belongs to the prior art disclosed in the art.

[0066] Through the above arrangement, damage to the booster pump 4, the first reverse osmosis membrane 5, and the second reverse osmosis membrane 6 can be reduced.

[0067] In some embodiments, Figure 1 As shown, the waste liquid purification treatment device also includes a raw water tank 1 and a concentrated water tank 8. The raw water tank 1 is connected to the inlet of the pretreatment component and is used to receive low-level waste liquid. The inlet of the concentrated water tank 8 is respectively connected to the concentrated water outlet of the first reverse osmosis membrane 5 and the concentrated water outlet of the second reverse osmosis membrane 6, and the outlet of the concentrated water tank 8 is connected to the raw water tank 1, which is used to collect the low-level concentrated liquid and then transport the low-level concentrated liquid to the raw water tank 1.

[0068] like Figure 1 , Figure 3 As shown, the concentrated water outlet of the first reverse osmosis membrane 5 and the concentrated water outlet of the second reverse osmosis membrane 6 are merged and connected to the inlet of the concentrated water tank 8 through the first confluence pipe.

[0069] A ball valve SV107 is provided between the first confluence pipe and the concentrated water outlet of the first reverse osmosis membrane 5 , a ball valve SV108 is provided between the first confluence pipe and the concentrated water outlet of the second reverse osmosis membrane 6 , and a ball valve SV109 is provided on the first confluence pipe.

[0070] Exemplarily, a immersion liquid level meter LT may be provided in the concentrated water tank 8 . The immersion liquid level meter LT is provided with different scales for monitoring the liquid level in the concentrated water tank 8 .

[0071] A ball valve SV112 is also provided between the outlet of the concentrated water tank 8 and the raw water tank 1 .

[0072] For example, the concentration of sodium nitrate in the low-level concentrated liquid after being concentrated by the second reverse osmosis membrane 6 is 40 g / L. At this time, the low-level concentrated liquid is input into the raw water tank 1, which can increase the initial concentration of the low-level waste liquid in the raw water tank 1. After the low-level waste liquid with the increased initial concentration is concentrated again by the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6, the concentration of sodium nitrate is increased to 50 g / L, and pure water is separated again.

[0073] According to the recovery rate formula of the reverse osmosis system: R = F1 / F2 × 100%, where R represents the recovery rate, F1 is the water production of the reverse osmosis system (the total amount of pure water separated by the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6), and F2 is the water inlet of the reverse osmosis system (the total amount of low-level radioactive waste liquid entering the raw water tank 1). When the total amount of the water inlet F2 of the reverse osmosis system remains unchanged, the low-level radioactive concentrated liquid can be recycled to separate pure water again, increasing the water production F1 of the reverse osmosis system. Therefore, the overall recovery rate of the waste liquid purification treatment device can be increased.

[0074] And through the above settings, the low-level radioactive concentrated liquid can be mixed with the low-level radioactive waste liquid in the raw water tank 1 and concentrated again to increase the concentration of the low-level radioactive concentrated liquid, thereby reducing the total amount of the finally generated low-level radioactive concentrated liquid.

[0075] In some embodiments, as Figure 1 shown, a circulation pump 10 is provided between the outlet of the concentrated water tank 8 and the raw water tank 1.

[0076] Exemplarily, the circulation pump 10 can be a general water pump.

[0077] The circulation pump 10 is arranged between the ball valve SV112 and the raw water tank 1, and a ball valve SV113 is arranged between the circulation pump 10 and the raw water tank 1.

[0078] The circulation pump 10 is used to transport the low-level radioactive concentrated liquid in the concentrated water tank 8 to the raw water tank 1.

[0079] In some embodiments, as Figure 1 shown, the pure water outlets of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 are both connected to the raw water tank 1 for transporting the pure water separated from the filtered waste liquid after passing through the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 into the raw water tank 1.

[0080] As Figure 1 shown, the pure water outlets of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 converge and are connected to the raw water tank 1 through the second confluence pipeline. A ball valve SV111 is arranged on the second confluence pipeline.

[0081] Through the above settings, the pure water can enter the raw water tank 1 to wash the raw water tank 1 or be used to maintain the liquid level in the raw water tank 1, and the pure water entering the raw water tank 1 will be separated by the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 again, increasing the total amount of pure water generated by the waste liquid purification treatment device, that is, increasing the water production F1 of the reverse osmosis system. According to the recovery rate formula of the reverse osmosis system again, the overall recovery rate of the waste liquid purification treatment device can be improved.

[0082] In some embodiments, as Figure 1As shown, the waste liquid purification treatment device further includes a chiller 9. The chiller 9 is connected to the raw water tank 1 and is used to cool the low-level radioactive waste liquid in the raw water tank 1.

[0083] Exemplarily, the chiller 9 can be a commonly used air-cooled chiller.

[0084] Those skilled in the art can understand that the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 in the waste liquid purification treatment device will generate high temperature during operation, thus accelerating the aging of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6.

[0085] By setting the chiller 9, the temperature of the low-level radioactive waste liquid in the raw water tank 1 can be reduced, so that when the low-level radioactive waste liquid flows through the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6, it cools the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6, avoiding affecting the service life of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6.

[0086] In some embodiments, the filtration accuracy of the security filter 3 is a, and 3μm ≤ a ≤ 5μm.

[0087] Exemplarily, the filtration accuracy a of the security filter 3 can be 3μm, 4μm or 5μm, etc.

[0088] The inventor found that after setting the filtration accuracy a of the security filter 3 within the above range, the removal effect of nuclide suspensions and colloids in the low-level radioactive waste liquid can be ensured. After inspection by the inventor, the removal rate of nuclide suspensions and colloids by the security filter 3 at this time is not less than 99%.

[0089] In some examples, as Figure 1 shown, the outlet of the feed pump 2 is also connected to the raw water tank 1, and a ball valve SV102 is provided between the outlet of the feed pump 2 and the raw water tank 1.

[0090] Through the above setting, a part of the low-level radioactive waste liquid can be re-transported to the raw water tank 1 to wash the raw water tank 1 and maintain the liquid level in the raw water tank 1.

[0091] In some examples, the raw water tank 1 and the concentrated water tank 8 are both made of 304 stainless steel, which can improve the corrosion resistance of the raw water tank 1 and the concentrated water tank 8.

[0092] As Figure 4 shown, Figure 4 shows the working principle of the waste liquid purification treatment device. The low-level radioactive waste liquid first enters the raw water tank, and then passes through the security filter under the action of the feed pump; then it enters the DTRO membrane module (i.e., the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6) under the action of the booster pump. A part of the pure water separated by the DTRO membrane module returns to the raw water tank, and the low-level radioactive concentrated waste liquid concentrated by the DTRO membrane module enters the raw water tank under the action of the circulation pump and circulates again.

[0093] The beneficial effects of the present invention are as follows. By adopting the technology of jointly treating low-level radioactive waste liquid with a pretreatment component and a membrane filtration component, not only can the purification process of low-level radioactive waste liquid be shortened, the operation energy consumption be reduced, but also the purification efficiency of low-level radioactive waste liquid can be improved. A part of the pure water passing through the DTRO membrane module returns to the original water tank, improving the water production recovery rate; the low-level radioactive concentrated waste liquid passing through the DTRO membrane module returns to the original water tank and is subjected to cyclic concentration treatment again, which can increase the final concentration of the low-level radioactive concentrated waste liquid, thereby reducing the total amount of low-level radioactive concentrated waste liquid to be finally treated.

[0094] Example 2:

[0095] The embodiment of the present invention also provides a low-level radioactive waste liquid purification treatment system for use in the low-level radioactive waste liquid treatment process. As Figure 1 shown, the low-level radioactive waste liquid purification treatment system includes a waste liquid tank 11, a waste liquid purification treatment device, and a product water tank 7. The waste liquid tank 11 is used to store low-level radioactive waste liquid and transport the low-level radioactive waste liquid to the waste liquid purification treatment device. The waste liquid purification treatment device is communicated with the waste liquid tank 11. The product water tank 7 is communicated with the pure water outlets of the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6 in the waste liquid purification treatment device, and is used to store the pure water separated by the first reverse osmosis membrane 5 and the second reverse osmosis membrane 6.

[0096] Exemplarily, both the waste liquid tank 11 and the product water tank 7 are made of stainless steel.

[0097] The waste liquid tank 11 can be communicated with the upstream low-level radioactive waste liquid pipeline, and the low-level radioactive waste liquid flows into the waste liquid tank 11 through the low-level radioactive waste liquid pipeline and is stored.

[0098] The product water tank 7 can store the pure water separated by the waste liquid purification treatment device and then recycle it, thereby improving the utilization rate of pure water.

[0099] Through the above settings, the low-level radioactive waste liquid can be concentrated to reduce the total amount of low-level radioactive concentrated liquid to be finally treated, and the pure water separated by the waste liquid purification treatment device can be stored and recycled, improving the recycling rate of water resources, and further improving the economic benefits of the low-level radioactive waste liquid purification treatment system. Moreover, the operation cost of the waste liquid purification treatment device is relatively low, which also reduces the operation cost of the low-level radioactive waste liquid purification treatment system.

[0100] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A waste liquid purification treatment device, characterized in that, Comprising: A pretreatment component for filtering the low-level radioactive waste flowing into the water tank to remove solid particles in the low-level radioactive waste, forming filtered waste liquid, and conveying the filtered waste liquid to the membrane filtration component; and, The membrane filtration component includes a first reverse osmosis membrane (5) and a second reverse osmosis membrane (6) connected in parallel. The operating pressure of the first reverse osmosis membrane (5) is less than the operating pressure of the second reverse osmosis membrane (6); the water inlets of the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6) are both connected to the outlet of the pretreatment component, and are used to obtain low-level radioactive concentrates with different concentrations of the filtered waste liquid respectively to separate pure water.

2. The waste liquid purification treatment device according to claim 1, wherein Both the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6) are disk tube reverse osmosis membranes; The operating pressure of the first reverse osmosis membrane (5) is P1, 60 bar ≤ P1 ≤ 80 bar, and the operating pressure of the second reverse osmosis membrane (6) is P2, 150 bar ≤ P2 ≤ 170 bar.

3. The waste liquid purification treatment device according to claim 2, characterized in that, The membrane filtration component further includes a booster pump (4); The inlet of the booster pump (4) is connected to the outlet of the pretreatment component, and the outlet of the booster pump (4) is respectively connected to the water inlets of the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6).

4. The waste liquid purification and treatment device according to claim 3, characterized in that, The membrane filtration component further includes: A first pressure transmitter arranged at the inlet of the booster pump (4) for detecting the pressure at the inlet of the booster pump (4); A second pressure transmitter arranged at the outlet of the booster pump (4) for detecting the pressure at the outlet of the booster pump (4); and, A controller electrically connected to the first pressure transmitter, the second pressure transmitter and the booster pump (4) respectively, and is used to control the start and stop of the booster pump (4) according to the pressure at the inlet of the booster pump (4) and the pressure at the outlet of the booster pump (4).

5. The waste liquid purification treatment device according to claim 3, characterized in that, It further includes a raw water tank (1) and a concentrated water tank (8); The raw water tank (1) is connected to the inlet of the pretreatment component for receiving low-level radioactive waste; The inlet of the concentrated water tank (8) is respectively connected to the concentrated water outlets of the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6), and the outlet of the concentrated water tank (8) is connected to the raw water tank (1), and is used to collect the low-level radioactive concentrate and then convey the low-level radioactive concentrate into the raw water tank (1).

6. The waste liquid purification treatment device according to claim 5, wherein, A circulation pump (10) is arranged between the outlet of the concentrated water tank (8) and the raw water tank (1).

7. The waste liquid purification treatment device according to claim 5, characterized in that The pure water outlets of the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6) are both connected to the raw water tank (1), and are used to convey the pure water separated from the filtered waste liquid after passing through the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6) into the raw water tank (1).

8. The waste liquid purification treatment device according to claim 7, wherein, It further includes a chiller (9); The chiller (9) is connected to the raw water tank (1) for cooling the low-level radioactive waste in the raw water tank (1).

9. The waste liquid purification treatment device according to claim 5, characterized in that, The pretreatment component includes: A feeding pump (2) whose inlet is connected to the raw water tank (1); and, A security filter (3), whose inlet is communicated with the outlet of the feed pump (2), and whose outlet is communicated with the inlet of the booster pump (4), is used to filter solid particles in the low-level radioactive waste liquid to generate filtered waste liquid.

10. The waste liquid purification treatment device according to claim 9, characterized in that, The filtration accuracy of the security filter (3) is a, where 3μm ≤ a ≤ 5μm.

11. A low-level liquid waste purification and treatment system, characterized in that, Comprising: A waste liquid tank (11), which is used to store low-level radioactive waste liquid and convey the low-level radioactive waste liquid to the waste liquid purification and treatment device; The waste liquid purification and treatment device according to any one of claims 1-10, which is communicated with the waste liquid tank (11); and A product water tank (7), which is communicated with the pure water outlets of the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6) in the waste liquid purification and treatment device, and is used to store the pure water separated by the first reverse osmosis membrane (5) and the second reverse osmosis membrane (6).

Images