Single-stage non-contact membrane distillation wastewater treatment device and method thereof

Abstract

The application discloses a single-stage non-contact membrane distillation wastewater treatment device and a method thereof. The single-stage non-contact membrane distillation wastewater treatment device comprises an evaporation tower, a membrane distillation assembly, a fan, an evaporation heat exchange assembly, a temperature and humidity adjusting assembly, a cyclone water separator and a heating assembly. The evaporation tower, the fan, the evaporation heat exchange assembly, the temperature and humidity adjusting assembly and the cyclone water separator are sequentially connected in order. The cyclone water separator is further connected to the membrane distillation assembly. The membrane distillation assembly is arranged in the evaporation tower and located at the top of the evaporation tower. The heating assembly is connected to the evaporation tower for heating treatment of radioactive wastewater in the evaporation tower. The application is used for highly reducing the volume and deeply purifying the treatment of radioactive wastewater generated in nuclear power station operation and maintenance, nuclear accident emergency, spent fuel reprocessing plant production, hospital radiotherapy and the like.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and in particular to a single-stage non-contact membrane distillation wastewater treatment device and method. Background Technology

[0002] Large quantities of radioactive wastewater are generated in fields such as nuclear power plant operation and maintenance, nuclear accident emergency response, spent fuel reprocessing plant production, and hospital radiotherapy. To ensure environmental safety and public health, and to shorten the radioactive wastewater treatment process, this wastewater needs to be treated efficiently, economically, and effectively in terms of volume reduction and purification. Currently, traditional methods for treating radioactive wastewater mainly include filtration, ion exchange, evaporation and concentration, adsorption, biological treatment, or combinations of these processes. However, most of these methods involve complex system setups, high energy consumption, large amounts of solid waste generated, and high investment, operation, and maintenance costs.

[0003] Membrane distillation technology, which utilizes the characteristic of hydrophobic microporous membranes that only allow volatile components such as water vapor to pass through the membrane pores, is a membrane separation process driven by the pressure difference of gas molecules across the membrane. Maintaining a suitable temperature difference across the membrane is sufficient for the process. Therefore, membrane distillation technology has advantages such as simple equipment, mild operating conditions, and good purification effect, and can be widely used in wastewater treatment, concentration, and purification. However, in traditional membrane distillation technology, wastewater comes into direct contact with the membrane, which easily causes membrane fouling, pore blockage, and membrane hydrophilization. This results in short membrane lifespan, low and unstable flux, easy membrane damage, and difficulty in online monitoring. In addition, membrane distillation technology requires maintaining a large temperature difference across the membrane, leading to high energy consumption. Therefore, traditional membrane distillation technology is difficult to meet actual production needs. Summary of the Invention

[0004] Therefore, it is necessary to provide a single-stage non-contact membrane distillation wastewater treatment device. The single-stage non-contact membrane distillation wastewater treatment device of this invention can meet the needs of nuclear medicine departments, nuclear power plants, spent fuel processing plants, and other facilities for the treatment of radioactive wastewater.

[0005] One embodiment of this application provides a single-stage non-contact membrane distillation wastewater treatment device.

[0006] A single-stage non-contact membrane distillation wastewater treatment device includes an evaporation tower, a membrane distillation module, a blower, an evaporation heat exchange module, a temperature and humidity control module, a cyclone separator, and a heating module. The evaporation tower, blower, evaporation heat exchange module, temperature and humidity control module, and cyclone separator are connected sequentially. The cyclone separator is also connected to the membrane distillation module. The membrane distillation module is located inside the evaporation tower and near its top. The heating module is connected to the evaporation tower for heating the radioactive wastewater inside. The blower assists in the diffusion of high-humidity gas from the evaporation tower through the membrane distillation module. The evaporation heat exchange module exchanges heat with high-temperature water vapor from the blower. The temperature and humidity control module cools the low-temperature water vapor after heat exchange from the evaporation heat exchange module. The cyclone separator separates the low-temperature water vapor and condensate from the temperature and humidity control module to produce purified liquid. The dry, cold air separated by the cyclone separator is circulated into the membrane distillation module.

[0007] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a flow detection component, which is disposed on the circulation pipe between the evaporator and the blower to detect the flow rate of high-temperature water vapor in the circulation pipe.

[0008] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a first temperature and humidity detection component, which is disposed on the circulation pipe between the evaporation tower and the blower to detect the temperature and humidity of the high-temperature water vapor in the circulation pipe.

[0009] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes an air supply pipe and an air supply valve. The air supply pipe is connected to the circulation pipe between the evaporation tower and the blower, and the air supply valve is installed on the air supply pipe to supply air to the circulation pipe between the evaporation tower and the blower.

[0010] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a pressure detection component disposed on the circulation pipe between the cyclone separator and the membrane distillation assembly for detecting the pressure of dry, cold air in the circulation pipe.

[0011] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a second temperature and humidity detection component, which is disposed on the circulation pipe between the cyclone separator and the membrane distillation assembly to detect the temperature and humidity of the dry and cold air in the circulation pipe.

[0012] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a purified liquid outlet pipe and a purified liquid outlet switch. The purified liquid outlet pipe is connected to the cyclone separator for discharging the purified liquid separated by the cyclone separator, and the purified liquid outlet switch is installed on the purified liquid outlet pipe.

[0013] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a compressor, a shell-and-tube heat exchanger, and a wastewater circulation pump. The evaporation tower, the heating assembly, and the shell-and-tube heat exchanger are circulatedly connected through heating pipes. The wastewater circulation pump is installed on the heating pipes and is used to realize the heat exchange of radioactive wastewater in the evaporation tower through the shell-and-tube heat exchanger and the heating assembly.

[0014] The shell-and-tube heat exchanger is also circulatedly connected to the evaporative heat exchange assembly via a heat pump system pipeline. The compressor is installed in the heat pump system pipeline, which contains refrigerant. The refrigerant passes through the evaporative heat exchange assembly to exchange heat with the high-temperature water vapor inside the assembly, thereby absorbing the heat from the high-temperature water vapor. The compressor is used to change the refrigerant in the heat pump system pipeline from normal temperature and pressure to high temperature and pressure before it is input into the shell-and-tube heat exchanger to exchange heat with the radioactive wastewater inside the shell-and-tube heat exchanger, thereby improving heating efficiency.

[0015] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device further includes a spiral nozzle installed inside the evaporation tower and close to the lower part of the membrane distillation assembly, with the spray direction of the spiral nozzle facing downwards towards the bottom of the evaporation tower, and the spiral nozzle connected to a heating pipe extending into the evaporation tower.

[0016] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device also satisfies at least one of the following conditions:

[0017] (1) The single-stage non-contact membrane distillation wastewater treatment device further includes a water replenishment pump, which is installed on the liquid inlet pipe of the evaporation tower for pumping in the radioactive wastewater to be treated.

[0018] (2) The membrane distillation assembly includes a hydrophobic membrane;

[0019] (3) The single-stage non-contact membrane distillation wastewater treatment device further includes a wastewater storage tank, which is connected to the evaporation tower through an inlet pipe;

[0020] (4) The single-stage non-contact membrane distillation wastewater treatment device also includes a drain valve, which is installed at the bottom drain port of the evaporation tower.

[0021] One embodiment of this application provides a single-stage non-contact membrane distillation wastewater treatment method.

[0022] A single-stage non-contact membrane distillation wastewater treatment method, using the aforementioned single-stage non-contact membrane distillation wastewater treatment device, includes the following steps:

[0023] Radioactive wastewater is introduced into the evaporation tower to a preset height;

[0024] The heating components are controlled to heat the radioactive wastewater in the evaporation tower until the average water temperature of the radioactive wastewater reaches a preset temperature.

[0025] The radioactive wastewater in the evaporation tower diffuses into the hot side of the membrane distillation assembly in the form of high-humidity gas at the preset temperature after evaporation. Water molecules in the high-humidity gas pass through the hydrophobic membrane in the middle of the membrane distillation assembly under pressure and enter the cold side, forming high-temperature water vapor 10°C to 20°C lower than the preset temperature. The high-temperature water vapor is transported to the evaporation heat exchange assembly through the circulation pipe and the fan for heat exchange to form low-temperature water vapor.

[0026] The temperature and humidity control component cools the low-temperature water vapor below 45°C after heat exchange with the evaporation heat exchange component and condenses it into purified water. The cyclone separator separates the low-temperature water vapor and condensate from the temperature and humidity control component to produce purified liquid. The dry and cold air separated by the cyclone separator is fed into the membrane distillation component for circulation.

[0027] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment method also satisfies at least one of the following conditions:

[0028] (1) Control the refrigerant circulation in the heat pump system pipeline to achieve heat exchange between the refrigerant and the high-temperature water vapor in the evaporation heat exchange component to form low-temperature water vapor;

[0029] (2) The compressor is controlled to change the refrigerant in the heat pump system pipeline from normal temperature and pressure to high temperature and high pressure through mechanical movement, and then transport it to the shell and tube heat exchanger to exchange heat with the radioactive wastewater in the shell and tube heat exchanger to improve the heating efficiency of the radioactive wastewater.

[0030] (3) Radioactive nuclides in radioactive wastewater include, but are not limited to, those that ... radioactive nuclides. 3 H, 131 I, 89 Sr、 99 mTr、 60 Co; The concentration of radionuclides in the radioactive wastewater is not less than 5 × 10⁻⁶. 6 Bq / L;

[0031] (4) The concentration of radionuclides in the produced purified liquid can be reduced to 168 Bq / L.

[0032] In the aforementioned single-stage non-contact membrane distillation wastewater treatment device, a high membrane flux can be achieved without a large temperature difference between the hot and cold sides of the membrane distillation module, resulting in low energy consumption requirements for maintaining the temperature difference between the two sides of the membrane distillation module. The blower increases the gas circulation speed within the circulation pipeline and also has a purging effect on the hydrophobic membrane surface on the membrane distillation module, keeping the hydrophobic membrane clean, less prone to fouling, eliminating the risk of membrane damage, reducing problems such as membrane hydrophilization and corrosion, extending the service life of the hydrophobic membrane, and enhancing the overall durability of the equipment. The aforementioned single-stage non-contact membrane distillation wastewater treatment device effectively removes pollutants from wastewater... 3 It has a highly efficient purification capability for non-volatile nuclides, ions, and molecules outside of H, and can purify radioactive nuclide concentrations of 5 × 10⁻⁶. 6 Bq / L contains 131 The nuclear wastewater purification method described in this application refers to purified water with a radionuclide concentration of less than 200 Bq / L. This application can be used not only for the high-volume reduction and deep purification of radioactive wastewater generated during nuclear power plant operation and maintenance, nuclear accident emergency response, spent fuel reprocessing plant production, and hospital radiotherapy, but also for seawater desalination and ultrapure water production.

[0033] The above-mentioned single-stage non-contact membrane distillation wastewater treatment device realizes the heat recovery function of high-temperature water vapor through a heat exchange circuit composed of a shell and tube heat exchanger, an evaporation heat exchange component, and a compressor. The recovered heat is used to heat the radioactive wastewater, further reducing energy consumption requirements.

[0034] The aforementioned single-stage non-contact membrane distillation wastewater treatment device is equipped with various sensors, such as flow detection components, first temperature and humidity detection components, pressure detection components, and second temperature and humidity detection components, which can monitor the operational stability of the equipment in real time and ensure the reliability of the equipment during long-term operation.

[0035] The aforementioned single-stage non-contact membrane distillation wastewater treatment device, by setting up a drain valve, periodically discharges the concentrated wastewater in the evaporation tower, keeping the radioactivity concentration of the wastewater in the evaporation tower at a reasonable level and ensuring the effectiveness of wastewater purification during operation. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0038] Figure 1 This is a schematic diagram of a single-stage non-contact membrane distillation wastewater treatment device according to an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures

[0040] 10. Single-stage non-contact membrane distillation wastewater treatment device; 100. Evaporation tower; 200. Membrane distillation module; 300. Fan; 400. Evaporation heat exchange module; 500. Temperature and humidity control module; 600. Cyclone separator; 700. Heating module; 800. Flow detection component; 900. First temperature and humidity detection component; 1000. Air supply valve; 1100. Pressure detection component; 1200. Second temperature and humidity detection component; 1300. Purified liquid outlet switch; 1400. Compressor; 1500. Shell and tube heat exchanger; 1600. Wastewater circulation pump; 1700. Spiral nozzle; 1800. Water supply pump; 1900. Sewage valve; 101. Circulation pipeline; 102. Heat pump system pipeline; 103. Heating pipeline; 104. Air supply pipeline; 105. Liquid inlet pipeline. Detailed Implementation

[0041] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0046] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0047] In this application, when numerical intervals (i.e., numerical ranges) are mentioned, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] This application provides a single-stage non-contact membrane distillation wastewater treatment device to solve at least one of the following technical problems existing in the treatment of radioactive wastewater in conventional technologies: (1) When using filtration, ion exchange, evaporation concentration, adsorption, biological treatment or a combination of these processes, the system setup is complex, energy consumption is high, the amount of solid waste generated is large, and the investment, operation and maintenance costs are high; (2)

[0050] When treating radioactive wastewater, membrane distillation technology has problems such as short membrane life, low and unstable flux, easy membrane damage and difficulty in online detection; (3) Membrane distillation technology requires maintaining a large temperature difference on both sides of the membrane, resulting in high energy consumption. The following will describe the single-stage non-contact membrane distillation wastewater treatment device with reference to the attached drawings.

[0051] The single-stage non-contact membrane distillation wastewater treatment device 10 provided in this application embodiment is exemplary; please refer to [link to example]. Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a single-stage non-contact membrane distillation wastewater treatment device 10 provided in an embodiment of this application. The single-stage non-contact membrane distillation wastewater treatment device 10 of this application can be used for radioactive wastewater treatment, meeting the needs of nuclear medicine departments, nuclear power plants, spent fuel processing plants, and other facilities for radioactive wastewater treatment.

[0052] To more clearly illustrate the structure of the single-stage non-contact membrane distillation wastewater treatment device 10, the following description of the single-stage non-contact membrane distillation wastewater treatment device 10 will be provided in conjunction with the accompanying drawings.

[0053] For example, please refer to Figure 1 As shown, a single-stage non-contact membrane distillation wastewater treatment device 10 includes an evaporation tower 100, a membrane distillation module 200, a blower 300, an evaporation heat exchange module 400, a temperature and humidity control module 500, a cyclone separator 600, and a heating module 700. The evaporation tower 100, blower 300, evaporation heat exchange module 400, temperature and humidity control module 500, and cyclone separator 600 are connected sequentially. The cyclone separator 600 is also connected to the membrane distillation module 200. The membrane distillation module 200 is disposed inside the evaporation tower 100 and near the top of the evaporation tower 100. A heating element 700 is connected to an evaporation tower 100 for heating the radioactive wastewater within the evaporation tower 100. A blower 300 assists in the diffusion of high-humidity gas within the evaporation tower 100 through the membrane distillation element 200. Furthermore, the blower 300 also increases the gas circulation speed within the circulation pipe 101 and purges the hydrophobic membrane surface on the membrane distillation element 200. An evaporation heat exchange element 400 exchanges heat with the high-temperature water vapor from the blower 300. A temperature and humidity control element 500 cools the low-temperature water vapor after heat exchange with the evaporation heat exchange element 400. A cyclone separator 600 separates the low-temperature water vapor from the temperature and humidity control element 500 to produce purified liquid. The dry, cold air separated by the cyclone separator 600 is then circulated into the membrane distillation element 200.

[0054] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a flow detection component 800. The flow detection component 800 is disposed on the circulation pipe 101 between the evaporator 100 and the blower 300 for detecting the flow rate of high-temperature water vapor in the circulation pipe 101.

[0055] In some embodiments, the flow detection component 800 may be a flow sensor.

[0056] In some embodiments, the heating component 700 may be an electromagnetic heater. An electromagnetic heater is a device that generates heat using the principle of electromagnetic induction. The working principle of an electromagnetic heater is as follows: Electromagnetic heating is based on Faraday's law of electromagnetic induction. When an alternating current passes through a coil, a changing magnetic field is generated around the coil. If a conductive material (usually a metal) is placed within this magnetic field, eddy currents are generated within the material. These eddy currents encounter resistance as they flow within the conductor, thereby generating heat. The advantages of electromagnetic heaters include: high efficiency and energy saving: high energy conversion efficiency, with most of the input energy being converted into heat energy; rapid heating: able to quickly reach the required temperature; clean and environmentally friendly: no combustion process, producing no waste gas or harmful substances; high safety: the surface does not directly heat up, reducing the risk of burns; easy control: the heating speed and temperature can be precisely controlled by adjusting the current.

[0057] In some embodiments, the temperature and humidity regulating component 500 may be a surface cooler. A surface cooler typically consists of a series of heat exchange tubes and fins, with hot steam circulating inside the heat exchange tubes. When outside air passes through these fins, the air exchanges heat with the hot steam inside the heat exchange tubes, thereby cooling the hot steam inside the tubes. Simultaneously, as the hot steam passes through the surface cooler, some water vapor condenses into water droplets, thus reducing the humidity and temperature in the pipes. The surface cooler structure includes: heat exchange tubes: for passing high-temperature gas; fins: to increase the heat exchange area and improve heat exchange efficiency; and a frame: to support the entire structure and facilitate installation in an air conditioning system. The main functions of the surface cooler include: cooling: lowering the temperature of the medium inside the tubes through heat exchange; and dehumidification: during the exchange with outside air, moisture inside the tubes condenses into water droplets, thereby removing humidity from the pipes.

[0058] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a first temperature and humidity detection component 900. The first temperature and humidity detection component 900 is disposed on the circulation pipe 101 between the evaporation tower 100 and the fan 300 to detect the temperature and humidity of the high-temperature water vapor in the circulation pipe 101.

[0059] In some embodiments, the first temperature and humidity detection component 900 may be a temperature and humidity sensor.

[0060] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes an air supply pipe 104 and an air supply valve 1000. The air supply pipe 104 is connected to the circulation pipe 101 between the evaporator 100 and the blower 300, and the air supply valve 1000 is installed on the air supply pipe 104 for supplying air to the circulation pipe 101 between the evaporator 100 and the blower 300.

[0061] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a pressure detection component 1100. The pressure detection component 1100 is disposed on the circulation pipe 101 between the cyclone separator 600 and the membrane distillation assembly 200 for detecting the pressure of the dry, cold air within the circulation pipe 101.

[0062] In some embodiments, the pressure detection component 1100 may be a pressure sensor.

[0063] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a second temperature and humidity detection component 1200. The second temperature and humidity detection component 1200 is disposed on the circulation pipe 101 between the cyclone separator 600 and the membrane distillation assembly 200 for detecting the temperature and humidity of the dry and cold air in the circulation pipe 101.

[0064] In some embodiments, the second temperature and humidity detection component 1200 may be a temperature and humidity sensor. A temperature and humidity sensor is a device that can detect and measure the ambient temperature and humidity. It is widely used in many industries. The temperature and humidity sensor integrates a temperature sensor and a humidity sensor, and can convert the physical quantities of temperature and humidity into electrical signals, which are easy for electronic devices to read and process.

[0065] The aforementioned single-stage non-contact membrane distillation wastewater treatment device 10 is equipped with various sensors, such as a flow detection component 800, a first temperature and humidity detection component 900, a pressure detection component 1100, and a second temperature and humidity detection component 1200, which can monitor the operational stability of the equipment in real time and ensure the reliability of the equipment during long-term operation.

[0066] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a purified liquid outlet pipe and a purified liquid outlet switch 1300. The purified liquid outlet pipe is connected to a cyclone separator 600 for discharging the purified liquid separated by the cyclone separator 600. The purified liquid outlet switch 1300 is installed on the purified liquid outlet pipe. When the purified liquid accumulates to a certain amount, the purified liquid outlet switch 1300 is opened to discharge it.

[0067] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a compressor 1400, a shell-and-tube heat exchanger 1500, and a wastewater circulation pump 1600. The evaporation tower 100, heating assembly 700, and shell-and-tube heat exchanger 1500 are circulated together via heating pipe 103. The wastewater circulation pump 1600 is installed in the heating pipe 103. The wastewater circulation pump 1600 is used to achieve heat exchange of radioactive wastewater in the evaporation tower 100 through the shell-and-tube heat exchanger 1500 and heating through the heating assembly 700. The shell-and-tube heat exchanger 1500 is also circulated together with the evaporation heat exchange assembly 400 via a heat pump system pipe 102. The compressor 1400 is installed in the heat pump system pipe 102. A refrigerant is provided in the heat pump system pipe 102. The refrigerant passes through the evaporation heat exchange assembly 400 to exchange heat with the high-temperature water vapor within the evaporation heat exchange assembly 400, thereby absorbing the heat from the high-temperature water vapor. The compressor 1400 is used to change the refrigerant in the heat pump system pipeline 102 from normal temperature and pressure to high temperature and high pressure before it is introduced into the shell-and-tube heat exchanger 1500 to exchange heat with the radioactive wastewater in the shell-and-tube heat exchanger 1500, thereby improving heating efficiency. The single-stage non-contact membrane distillation wastewater treatment device 10 of this application realizes the heat recovery function of high-temperature water vapor through the heat exchange loop composed of the shell-and-tube heat exchanger 1500, the evaporation heat exchange component 400, and the compressor 1400. The recovered heat is used to heat the radioactive wastewater, further reducing energy consumption requirements.

[0068] It should be noted that in the actual treatment process, the heating component 700 can be started first to raise the temperature of the radioactive wastewater to the preset temperature, and then the heat pump system is started. The shell and tube heat exchanger 1500 is used to heat the radioactive wastewater by utilizing the heat exchange of the evaporation heat exchange component 400. The heat pump system has a high COP (COP greater than 3.5) to reduce energy consumption.

[0069] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 also includes a spiral nozzle 1700. The spiral nozzle 1700 is installed inside the evaporation tower 100 and near the bottom of the membrane distillation assembly 200. The spray direction of the spiral nozzle 1700 is downward towards the bottom of the evaporation tower 100, and the spiral nozzle 1700 is connected to a heating pipe 103 extending into the evaporation tower 100. The spiral nozzle 1700 is a special liquid or gas dispersion device designed based on a spiral internal structure. Spiral nozzles 1700 have wide applications in various fields such as industry, agriculture, fire fighting, and sanitation. The spiral nozzle 1700 works by cutting the fluid into fine droplets through its internal spiral channels, thereby forming a uniform spray pattern.

[0070] In this application, the refrigerant in the heat pump system pipeline is changed from normal temperature and pressure to high temperature and high pressure by the mechanical movement of the compressor 1400 and then transported to the shell and tube heat exchanger 1500 to exchange heat with the radioactive wastewater in the shell and tube heat exchanger 1500 to improve the heating efficiency of the radioactive wastewater. At this time, the radioactive wastewater in the heating pipe 103 is sprayed downward from the spiral nozzle 1700 in the form of a high temperature gas-liquid mixture. The downward spray direction ensures that the radioactive wastewater does not come into direct contact with the membrane distillation module 200. In addition, since the membrane distillation module 200 is close to the top of the evaporation tower 100, the water level of the radioactive wastewater to be treated in the evaporation tower 100 is lower than that of the membrane distillation module 200, thus realizing a non-contact membrane distillation wastewater treatment method.

[0071] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 also includes a makeup water pump 1800. The makeup water pump 1800 is installed on the inlet pipe 105 of the evaporator 100 for pumping in the radioactive wastewater to be treated.

[0072] In some embodiments, the membrane distillation assembly 200 includes a hydrophobic membrane. The membrane distillation assembly 200 is divided into three parts: a hot side, a hydrophobic membrane, and a cold side. An internal suction pipe is provided in the membrane distillation assembly 200, located on the cold side, for suctioning high-temperature water vapor that has passed through the hydrophobic membrane. High-temperature, high-humidity gas evaporated in the evaporation tower 100 diffuses to the hot side and is blocked by the hydrophobic membrane. Water molecules pass through the hydrophobic membrane via the pressure difference between the two sides and enter the cold side for purification. The purified high-temperature water vapor is then transported to the next stage by the fan 300.

[0073] In some embodiments, the membrane distillation assembly 200 can be replaced with a hydrophobic membrane of different pore sizes and materials, depending on the actual use.

[0074] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment device 10 further includes a wastewater storage tank. The wastewater storage tank is connected to the evaporation tower 100 via an inlet pipe 105. The wastewater storage tank can store radioactive wastewater to be treated; once a certain amount of radioactive wastewater has been stored, membrane distillation wastewater treatment can proceed. The radioactive wastewater that can be stored in the wastewater storage tank includes wastewater containing radioactive materials generated from nuclear power plant operation, nuclear facility production, and radiotherapy in hospital nuclear medicine departments. 89 Sr、 133 Cs、 60 Co、 99 mTr、 3 H, 131 Wastewater containing Class I radioactive isotopes. The wastewater storage tank is not shown in the attached diagram.

[0075] The single-stage non-contact membrane distillation wastewater treatment device 10 also includes a drain valve 1900. The drain valve 1900 is installed at the bottom drain outlet of the evaporation tower 100. By installing the drain valve 1900, the aforementioned single-stage non-contact membrane distillation wastewater treatment device 10 periodically discharges the concentrated wastewater from the evaporation tower 100, maintaining the radioactivity concentration of the wastewater within the evaporation tower 100 at a reasonable level and ensuring the effectiveness of wastewater purification during operation. The concentration of radioactive wastewater in the evaporation tower 100 gradually increases as evaporation proceeds; therefore, periodically discharging high-concentration radioactive wastewater ensures the controllability of the radioactive wastewater concentration within the evaporation tower 100. The discharged radioactive wastewater can be returned to a wastewater storage tank or transported to other treatment systems.

[0076] In this application, the cyclone separator 600 operates on the following principle: Compressed air or steam enters the cylinder of the cyclone separator 600 tangentially, causing the gas to rotate at high speed inside the cylinder. During this rotation, larger droplets, due to their greater inertial centrifugal force, are thrown against the cylinder wall. Upon contact with the cylinder wall, these droplets accumulate and slide down the wall to the water accumulation area at the bottom. The cyclone separator 600 is typically equipped with an automatic drainage device, such as a steam trap or a float-type automatic drain, to periodically remove accumulated water without manual intervention. The advantages of using a cyclone separator 600 include simple structure, low maintenance costs, and large processing capacity.

[0077] One embodiment of this application provides a single-stage non-contact membrane distillation wastewater treatment method.

[0078] In this document, unless otherwise stated, the reaction steps may be performed in the order described herein or not. For example, other steps may be included between reaction steps, and the order of reaction steps may be appropriately interchanged. This is something that those skilled in the art can determine based on conventional knowledge and experience. Preferably, the reaction methods described herein are performed sequentially.

[0079] A single-stage non-contact membrane distillation wastewater treatment method, using the aforementioned single-stage non-contact membrane distillation wastewater treatment device 10, includes the following steps:

[0080] S1. Introduce radioactive wastewater into evaporator 100 to a preset height. The water level at the preset height in evaporator 100 must be lower than that of membrane distillation module 200.

[0081] S2. Control the heating component 700 and the heat pump system to heat the radioactive wastewater in the evaporation tower 100 until the average water temperature of the radioactive wastewater reaches the preset temperature, then stop the heating component 700 and use the heat pump system to stably heat and maintain the temperature.

[0082] S3. The radioactive wastewater in the evaporation tower 100 diffuses into the hot side of the membrane distillation module 200 in the form of high-humidity gas after evaporation. Water molecules in the high-humidity gas pass through the hydrophobic membrane in the middle of the membrane distillation module 200 under pressure and enter the cold side. The high-temperature water vapor formed is 10°C to 20°C lower than the preset temperature and is transported to the evaporation heat exchange module 400 by the fan 300 through the circulation pipe 101 for heat exchange to form low-temperature water vapor.

[0083] S4. The temperature and humidity control component 500 cools the low-temperature water vapor below 45°C after heat exchange by the evaporation heat exchange component 400. The cyclone separator 600 separates the low-temperature water vapor from the temperature and humidity control component 500 to produce purified liquid. The dry and cold air separated by the cyclone separator 600 is fed into the membrane distillation component 200 for circulation.

[0084] In some embodiments, the preset temperature in step S2 is 100℃~120℃.

[0085] In some embodiments, in step S1, radioactive wastewater is introduced into the evaporation tower 100 to a preset height of 40% to 80% of the tower's height. Preferably, the radioactive wastewater is introduced into the evaporation tower 100 to a preset height of 60% to 70% of the tower's height.

[0086] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment method further includes the following steps: controlling the refrigerant circulation in the heat pump system pipeline 102 to achieve heat exchange between the refrigerant and the high-temperature water vapor in the evaporation heat exchange component 400 to form low-temperature water vapor.

[0087] In some embodiments, the single-stage non-contact membrane distillation wastewater treatment method further includes the following steps: controlling the compressor 1400 to mechanically change the refrigerant in the heat pump system pipeline 102 from normal temperature and pressure to a high temperature and high pressure state, and then delivering it to the shell-and-tube heat exchanger 1500 to exchange heat with the radioactive wastewater in the shell-and-tube heat exchanger 1500 to improve the heating efficiency of the radioactive wastewater. The heating component 700 and the shell-and-tube heat exchanger 1500 can achieve dual heating of the radioactive wastewater in the evaporation tower 100 until the radioactive wastewater reaches the vaporization temperature required by the membrane distillation component 200. The liquid in the evaporation tower 100 is heated to the point of evaporation, and then the high-temperature, high-humidity gas flows to the hot side of the membrane distillation component 200 through a pressure difference formed by the spiral nozzle, and is distilled by the membrane distillation component 200.

[0088] Example 1

[0089] This embodiment provides a single-stage non-contact membrane distillation wastewater treatment method for radioactive wastewater. The radioactive nuclides in the wastewater include... 3H, the concentration of radioactive nuclides in the radioactive wastewater is 5 × 10⁻⁶. 6 Bq / L.

[0090] This embodiment provides a single-stage non-contact membrane distillation wastewater treatment method, using the aforementioned single-stage non-contact membrane distillation wastewater treatment device 10, including the following steps:

[0091] S1. Radioactive wastewater is introduced into evaporator 100 to half the height of evaporator 100, and the water level in evaporator 100 must be lower than that in membrane distillation module 200.

[0092] S2. Control the heating component 700 to heat the radioactive wastewater in the evaporation tower 100 until the average water temperature of the radioactive wastewater reaches the preset temperature, wherein the preset temperature is 100℃.

[0093] S3. The compressor 1400, through mechanical movement, changes the refrigerant in the heat pump system pipeline 102 from normal temperature and pressure to a high temperature and high pressure state, and then delivers it to the shell-and-tube heat exchanger 1500 to exchange heat with the radioactive wastewater inside the shell-and-tube heat exchanger 1500, thereby improving the heating efficiency of the radioactive wastewater. Through the heating component 700 and the shell-and-tube heat exchanger 1500, dual heating of the radioactive wastewater in the evaporation tower 100 can be achieved until the radioactive wastewater reaches the vaporization temperature required by the membrane distillation component 200.

[0094] S4. The radioactive wastewater in the evaporation tower 100 diffuses into the hot side of the membrane distillation module 200 in the form of a high-humidity gas with a humidity of 100% after evaporation. The water molecules in the high-humidity gas pass through the hydrophobic membrane in the middle of the membrane distillation module 200 and enter the cold side under the action of water pressure. The high-temperature water vapor of 80℃~90℃ formed is transported to the evaporation heat exchange module 400 by the fan 300 through the circulation pipe 101.

[0095] S5. High-temperature water vapor undergoes heat exchange through the evaporation heat exchange component 400 to form low-temperature water vapor at 45℃~55℃. The refrigerant in the heat pump system pipe 102 absorbs heat through heat exchange and then enters the compressor 1400 for compression. The refrigerant at normal temperature and pressure becomes a high-temperature and high-pressure state after compression and enters the shell and tube heat exchanger 1500 for heat exchange to heat the radioactive wastewater.

[0096] S6. The temperature and humidity control component 500 cools the low-temperature water vapor after heat exchange with the evaporative heat exchange component 400 to 45°C.

[0097] S7. The cyclone separator 600 is controlled to separate low-temperature water vapor from the temperature and humidity control component 500 to produce purified liquid. The dry and cold air separated by the cyclone separator 600 is fed into the membrane distillation component 200 for circulation.

[0098] S8. Turn on the purified liquid outlet switch at 1300 every 10 minutes to discharge the purified liquid.

[0099] S9. Open the drain valve 1900 every 7 days to periodically or quantitatively discharge the concentrated waste liquid in evaporator 100, and control the concentration of radioactive wastewater in evaporator 100 to 1.0 × 10⁻⁶. 5 ~1×10 7 Bq / L.

[0100] After the above treatment, the radioactive wastewater was tested. The concentration of radionuclides in the purified liquid treated by the single-stage non-contact membrane distillation wastewater treatment method in this embodiment was reduced to 168 Bq / L. This demonstrates that the single-stage non-contact membrane distillation wastewater treatment method of this embodiment can effectively treat radionuclides in radioactive wastewater. The hydrophobic membrane of the membrane distillation module 200 was tested and found to be undamaged and uncorroded, indicating that the fan 300 in this application increases the gas circulation speed within the circulation pipe 101, keeping the hydrophobic membrane clean and less prone to contamination.

[0101] In summary, in the above-mentioned single-stage non-contact membrane distillation wastewater treatment device 10, a high membrane flux can be achieved without a large temperature difference between the hot and cold sides of the membrane distillation module 200, and the energy consumption requirement for maintaining the temperature difference between the two sides of the membrane distillation module 200 is low. The blower 300 increases the gas circulation speed within the circulation pipe 101 and also has a purging effect on the hydrophobic membrane surface on the membrane distillation module 200, keeping the hydrophobic membrane clean and less prone to fouling, eliminating the risk of membrane damage, reducing problems such as membrane hydrophilization and corrosion, extending the service life of the hydrophobic membrane, and improving the overall durability of the equipment. The above-mentioned single-stage non-contact membrane distillation wastewater treatment device 10 effectively removes pollutants from wastewater. 3 This application possesses highly efficient purification capabilities for non-volatile nuclides, ions, and molecules outside of H. The radioactive nuclides in the radioactive wastewater that this application can treat include, but are not limited to, those contained in H-type radioactive wastewater. 3 H, 131 I, 89 Sr、 99 mTr、 60 Co can reduce the concentration of radionuclides to 5 × 10⁻⁶. 6 Bq / L contains 131 The nuclear wastewater purification method described in this application refers to purified water with a radionuclide concentration of less than 200 Bq / L. This application can be used not only for the high-volume reduction and deep purification of radioactive wastewater generated during nuclear power plant operation and maintenance, nuclear accident emergency response, spent fuel reprocessing plant production, and hospital radiotherapy, but also for seawater desalination and ultrapure water production.

[0102] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A single-stage non-contact membrane distillation wastewater treatment device, characterized in that, The system includes an evaporation tower, a membrane distillation module, a fan, an evaporation heat exchange module, a temperature and humidity control module, a cyclone separator, a heating module, and a spiral nozzle. The evaporation tower, fan, evaporation heat exchange module, temperature and humidity control module, and cyclone separator are connected sequentially. The cyclone separator is also connected to the membrane distillation module. The membrane distillation module is located inside the evaporation tower and near its top. The heating module is connected to the evaporation tower for heating the radioactive wastewater within it. The fan assists in the diffusion of high-humidity gases within the evaporation tower through the membrane distillation module. The heat exchange component is used to exchange heat with the high-temperature water vapor from the fan. The temperature and humidity control component is used to cool the low-temperature water vapor after heat exchange with the evaporation heat exchange component. The cyclone separator is used to separate the low-temperature water vapor from the temperature and humidity control component to produce purified liquid. The dry and cold air separated by the cyclone separator is input into the membrane distillation component for circulation. The spiral nozzle is installed in the evaporation tower and close to the bottom of the membrane distillation component. The spray direction of the spiral nozzle is downward towards the bottom of the evaporation tower. The spiral nozzle is connected to the heating pipe extending into the evaporation tower.

2. The single-stage non-contact membrane distillation wastewater treatment device according to claim 1, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also meets at least one of the following conditions: (1) The single-stage non-contact membrane distillation wastewater treatment device further includes a flow detection component, which is installed on the circulation pipe between the evaporator and the blower to detect the flow rate of high-temperature water vapor in the circulation pipe; (2) The single-stage non-contact membrane distillation wastewater treatment device further includes a first temperature and humidity detection component, which is installed on the circulation pipe between the evaporation tower and the blower to detect the temperature and humidity of the high-temperature water vapor in the circulation pipe.

3. The single-stage non-contact membrane distillation wastewater treatment device according to claim 1, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also includes an air supply pipe and an air supply valve. The air supply pipe is connected to the circulation pipe between the evaporation tower and the blower, and the air supply valve is installed on the air supply pipe to supply air to the circulation pipe between the evaporation tower and the blower.

4. The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 3, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also meets at least one of the following conditions: (1) The single-stage non-contact membrane distillation wastewater treatment device further includes a pressure detection component, which is installed on the circulation pipe between the cyclone separator and the membrane distillation assembly to detect the pressure of the dry and cold air in the circulation pipe. (2) The single-stage non-contact membrane distillation wastewater treatment device further includes a second temperature and humidity detection component, which is installed on the circulation pipe between the cyclone separator and the membrane distillation assembly to detect the temperature and humidity of the dry and cold air in the circulation pipe.

5. The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 3, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also includes a purified liquid outlet pipe and a purified liquid outlet switch. The purified liquid outlet pipe is connected to the cyclone separator for discharging the purified liquid separated by the cyclone separator. The purified liquid outlet switch is installed on the purified liquid outlet pipe.

6. The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 3, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also includes a compressor, a shell-and-tube heat exchanger, and a wastewater circulation pump. The evaporation tower, the heating components, and the shell-and-tube heat exchanger are circulatedly connected through heating pipes. The wastewater circulation pump is installed on the heating pipes. The wastewater circulation pump is used to realize the heat exchange of radioactive wastewater in the evaporation tower through the shell-and-tube heat exchanger and the heating components. The shell-and-tube heat exchanger is also circulatedly connected to the evaporative heat exchange assembly via a heat pump system pipeline. The compressor is installed in the heat pump system pipeline, which contains refrigerant. The refrigerant passes through the evaporative heat exchange assembly to exchange heat with the high-temperature water vapor inside the assembly, thereby absorbing the heat from the high-temperature water vapor. The compressor is used to change the refrigerant in the heat pump system pipeline from normal temperature and pressure to high temperature and pressure before it is input into the shell-and-tube heat exchanger to exchange heat with the radioactive wastewater inside the shell-and-tube heat exchanger, thereby improving heating efficiency.

7. The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 3, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also meets at least one of the following conditions: (1) The single-stage non-contact membrane distillation wastewater treatment device further includes a water replenishment pump, which is installed on the liquid inlet pipe of the evaporation tower for pumping in the radioactive wastewater to be treated. (2) The membrane distillation assembly includes a hydrophobic membrane; (3) The single-stage non-contact membrane distillation wastewater treatment device also includes a wastewater storage tank, which is connected to the evaporation tower through an inlet pipe.

8. The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 3, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device also includes a drain valve, which is installed at the bottom drain port of the evaporation tower.

9. A single-stage non-contact membrane distillation wastewater treatment method, characterized in that, The single-stage non-contact membrane distillation wastewater treatment device according to any one of claims 1 to 8 includes the following steps: Radioactive wastewater is introduced into the evaporation tower to a preset height; The heating component is controlled to heat the radioactive wastewater in the evaporation tower until the average water temperature of the radioactive wastewater reaches the preset temperature. The spiral nozzle inside the evaporation tower and near the bottom of the membrane distillation component is controlled to cut the radioactive wastewater fluid into fine droplets through its internal spiral channel, thereby forming a uniform spray pattern. The radioactive wastewater in the evaporation tower diffuses into the hot side of the membrane distillation assembly as a high-humidity gas at the preset temperature after evaporation. Water molecules in the high-humidity gas pass through the hydrophobic membrane in the middle of the membrane distillation assembly under pressure and enter the cold side, forming high-temperature water vapor 10°C to 20°C lower than the preset temperature. The high-temperature water vapor is transported to the evaporation heat exchange assembly through the circulation pipe and the fan for heat exchange to form low-temperature water vapor. The temperature and humidity control component cools the low-temperature water vapor below 45°C after heat exchange with the evaporation heat exchange component and condenses it into purified water. The cyclone separator separates the low-temperature water vapor and condensate from the temperature and humidity control component to produce purified liquid. The dry and cold air separated by the cyclone separator is fed into the membrane distillation component for circulation.

10. The single-stage non-contact membrane distillation wastewater treatment method according to claim 9, characterized in that, The single-stage non-contact membrane distillation wastewater treatment method also meets at least one of the following conditions: (1) Control the refrigerant circulation in the heat pump system pipeline to achieve heat exchange between the refrigerant and the high-temperature water vapor in the evaporation heat exchange component to form low-temperature water vapor; (2) The compressor is controlled to change the refrigerant in the heat pump system pipeline from normal temperature and pressure to high temperature and high pressure through mechanical movement, and then transport it to the shell and tube heat exchanger to exchange heat with the radioactive wastewater in the shell and tube heat exchanger to improve the heating efficiency of the radioactive wastewater. (3) Radioactive nuclides in radioactive wastewater include, but are not limited to, 3 H, 131 I, 89 Sr、 99 mTr、 60 Co; The concentration of radioactive nuclides in the radioactive wastewater is not less than 5 × 10⁻⁶. 6 Bq / L; (4) The concentration of radionuclides in the produced purified liquid can be reduced to 168 Bq / L.

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