An alkaline electrolyzer on-line extraction enriched heavy water unit, device, equipment, system and method

Abstract

The application discloses an alkaline electrolytic tank online extraction and enrichment heavy water unit, device, equipment, system and method, and belongs to the water electrolysis field. The alkaline electrolytic tank online extraction and enrichment heavy water device of the application comprises an alkaline electrolysis unit, a deuterium-rich water extraction unit and a separation and circulation unit. The deuterium-rich water extraction unit comprises a flash tank, a water ring vacuum pump, an alkali buffer tank and a deuterium-rich water storage device. The flash tank is communicated with the separation and circulation unit through a liquid inlet. The alkali solution evaporated from the flash tank is delivered to the alkali buffer tank through the water ring vacuum pump, and an alkali solution circulation loop is formed between the water ring vacuum pump and the alkali buffer tank. The gas evaporated from the flash tank is communicated to the deuterium-rich water storage device, and the deuterium-rich water storage device is communicated with the pump alkali inlet of the water ring vacuum pump through a non-condensable gas outlet. The water ring vacuum pump is used for continuously extracting vacuum from the flash tank, so that the pressure in the flash tank is maintained in a negative pressure state. The application continuously improves the deuterium substitution degree of heavy water online, and meets the efficient production requirements.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis technology, and more specifically, to an alkaline electrolytic cell for online extraction and enrichment of heavy water, a device, equipment, system, and method. Background Technology

[0002] Currently, there are two main technologies for increasing deuterium content in water using electrolysis: alkaline water electrolysis and proton exchange membrane (PEM) water electrolysis. The essential difference lies in the form of the electrolyte used: ALK technology uses liquid electrolytes (such as aqueous solutions of KOH or NaOH), while PEM technology uses solid proton exchange membranes as the electrolyte. Both types of electrolysis technologies can achieve deuterium enrichment operations from laboratory scale to small-scale industrial scale.

[0003] Alkaline water electrolysis (ALK) is one of the most mature and widely used water electrolysis hydrogen production devices. It mainly uses alkaline electrolyte solutions (such as KOH and NaOH) to electrolyze water into hydrogen (H2) and oxygen (O2). It has the characteristics of low cost and high reliability, and is especially suitable for large-scale stationary hydrogen production. It is one of the core technologies of the current hydrogen energy industry.

[0004] Proton exchange membrane battery (PEM) usually refers to proton exchange membrane fuel cell (PEMFC), which is a high-efficiency power generation device that uses proton exchange membrane (PEM) as electrolyte. It has the advantages of fast start-up at low temperatures, high power density, and zero emissions, and is widely used in transportation, portable power sources and distributed energy fields.

[0005] Alkaline water electrolysis and proton exchange membrane water electrolysis operate at near-ambient temperatures (typically from ambient temperature to 90°C). Hydrogen production using ALK (Alkaline Water Electrolyzer) is now a mature technology and is commercially available in megawatt (MW) scale electrolysis units. ALK electrolyzers use KOH aqueous solution as the liquid electrolyte. Compared to PEM (Proton Exchange Membrane) electrolyzers, ALK electrolyzers offer advantages such as lower cost per unit hydrogen production and higher throughput, making them suitable for the first few stages of a series deuterium extraction unit. However, as deuterium enriches during electrolysis, alkali also concentrates, which is detrimental to continuous operation control. Therefore, a high-efficiency evaporation device is needed to treat the alkaline solution.

[0006] Based on this, patent CN105408234B discloses an electrolytic enrichment method for heavy water, which includes: enriching heavy water by electrolysis using an alkaline electrolytic cell, wherein the alkaline electrolytic cell includes an anode chamber for accommodating an anode, a cathode chamber for accommodating a cathode, and a diaphragm. In this method, electrolyte prepared by adding high-concentration alkaline water to raw water containing heavy water is circulated from a circulation tank to the anode and cathode chambers. An anode-side gas-liquid separator and an anode-side water seal device are connected to the anode chamber, and a cathode-side gas-liquid separator and a cathode-side water seal device are connected to the cathode chamber. While continuously electrolyzing, the alkaline concentration in the electrolyte supplied to the two electrolysis chambers is maintained at a constant concentration by circulating the electrolyte to the circulation tank. Gases generated from the electrolyte are separated from the anode-side and cathode-side gas-liquid separators. However, due to the limitation of gas separation efficiency during alkaline electrolysis, the separation of hydrogen isotopes in the electrolyte is limited, making it impossible to continuously increase the deuteration degree of heavy water online. The enrichment concentration of heavy water is limited and cannot meet the deuteration degree of commercially available heavy water. Summary of the Invention

[0007] 1. The technical problem that the invention aims to solve In view of the insufficient efficiency of existing technologies in improving the deuteration degree of heavy water electrolysis, this invention aims to provide an online extraction and enrichment unit, device, equipment, system and method for heavy water in an alkaline electrolytic cell, which helps to continuously improve the deuteration degree of heavy water online, meet the requirements of high-efficiency production, reduce energy consumption, and is suitable for industrial production.

[0008] 2. Technical Solution To achieve the above objectives, the technical solution provided by the present invention is as follows: The present invention discloses an online extraction and enrichment unit for heavy water in an alkaline electrolytic cell, comprising a deuterium-rich water extraction unit, which includes a flash tank, a water ring vacuum pump, an alkaline buffer tank, and a deuterium-rich water storage device. The flash tank has a liquid inlet for receiving the alkaline solution after electrolytic separation, and a liquid outlet connected to the alkaline inlet of the water ring vacuum pump. The water ring vacuum pump delivers the alkaline solution to the alkaline buffer tank, and an alkaline solution circulation loop is formed between the water ring vacuum pump and the alkaline buffer tank. The flash tank has a tank gas outlet connected to a deuterium-rich water storage tank, and the deuterium-rich water storage tank has a storage non-condensable gas outlet connected to the pump alkali inlet of the water ring vacuum pump.

[0009] Furthermore, the water ring vacuum pump continuously draws a vacuum into the flash tank, maintaining a negative pressure state inside the flash tank at -88 to -82 kPa.

[0010] In this invention, the high-temperature alkaline solution generated by the alkaline electrolysis unit is directly fed into a flash tank for flash separation. During operation of the electrolysis cell, the electrical energy corresponding to the electrode overpotential is entirely dissipated into the alkaline solution in the form of Joule heat, maintaining the alkaline solution temperature stably at 55–90°C. This Joule heat power is significantly greater than the heat power required to evaporate deuterium-rich water in the flash tank. However, under normal pressure conditions, it is difficult to evaporate the deuterium-rich water from the alkaline solution at this temperature. Therefore, this invention utilizes a water ring vacuum pump to evacuate the flash tank, reducing the surface pressure inside the flash tank to -88 to -82 kPa. According to the principle of phase equilibrium, the saturated vapor pressure of water decreases significantly with decreasing ambient pressure, corresponding to a decrease in boiling point to 60–65°C. At this point, the sensible heat carried by the high-temperature alkaline solution entering the flash tank exceeds the latent heat of vaporization required to vaporize the deuterium-rich water under the negative pressure condition. The alkaline solution is in a superheated state, and the deuterium-rich water escapes rapidly from the alkaline solution in the form of steam. Flash separation can be completed spontaneously without the need for any external heating, effectively improving the extraction efficiency of deuterium-rich water.

[0011] Furthermore, during the flash evaporation process, the temperature of the alkaline solution decreases slightly and its concentration increases due to the evaporation of some water, until a new equilibrium is reached between the temperature of the alkaline solution and its boiling point under the pressure of the flash tank. In other words, this invention, by employing a water ring vacuum pump, does not use heating but rather reduces the pressure inside the flash tank to "release" the sensible heat of the alkaline solution itself, enabling it to spontaneously complete the vaporization and separation of deuterium-rich water without the need for an external heat source. Using the above design, this application fully utilizes the inherent thermal characteristics of the alkaline electrolyzer, simplifying the evaporation process, which would otherwise require external steam or electric heating, into a process driven solely by the electrolytic heat carried by the alkaline solution itself. This eliminates the need for an external heat source at the source, significantly reducing system operating energy consumption and equipment investment, and making the entire enrichment process thermodynamically more efficient and simpler.

[0012] Furthermore, in this invention, a condenser is provided between the liquid outlet of the flash tank and the alkali inlet of the water ring vacuum pump. The alkali liquid evaporated in the flash tank is condensed by the condenser and then enters the water ring vacuum pump, and is transported to the alkali buffer tank.

[0013] Specifically, in practice, the flash tank has a liquid inlet, a gas outlet, and a liquid outlet. The liquid inlet is connected to the alkaline electrolysis unit, specifically to the liquid outlet of the cathode gas-liquid separator. The liquid outlet of the flash tank is connected to the alkali inlet of the water ring vacuum pump, and the gas outlet is connected to the deuterium-rich water storage tank. A condenser (type 3) is installed on the connecting pipe between the flash tank and the water ring vacuum pump. The concentrated alkali outlet of the condenser (type 3) is connected to the alkali inlet of the water ring vacuum pump, which can effectively reduce the alkali temperature.

[0014] It should be noted that the concentrated alkali solution discharged from the bottom of the flash tank has a higher alkali concentration and a lower temperature, resulting in a lower saturated vapor pressure. After being discharged from the flash tank, this alkali solution is piped to the alkali solution inlet of the water ring vacuum pump. The alkali solution inlet of the water ring vacuum pump is the area with the lowest pressure in the system, with its suction pressure lower than the operating pressure of the flash tank. Practical experience has shown that if this alkali solution directly enters the water ring vacuum pump, it may cause cavitation, leading to increased pump vibration, increased noise, and erosion damage to the impeller and pump casing, threatening equipment lifespan and vacuum stability.

[0015] This invention incorporates a third condenser, which forces the concentrated alkali solution discharged from the flash tank to cool down. By lowering the temperature of the alkali solution, it can maintain a stable liquid phase state when entering the water ring vacuum pump at a lower pressure environment. This ensures uniform gas-liquid phase distribution within the pump, eliminates the risk of cavitation at its source, and guarantees the safe and reliable operation of the water ring vacuum pump.

[0016] Furthermore, a condenser four is installed between the flash tank's gas outlet and the deuterium-rich water storage tank. The gas evaporated in the flash tank is condensed by condenser four before entering the deuterium-rich water storage tank. Specifically, the deuterium-rich water storage tank has a storage deuterium-rich water inlet, a storage non-condensable gas outlet, a storage non-condensable gas discharge port, and a storage deuterium-rich water outlet. The flash tank gas outlet is connected to the inlet of condenser four, the condenser four outlet is connected to the storage deuterium-rich water inlet, the storage non-condensable gas outlet is connected to the alkali inlet of the water ring vacuum pump, and the storage non-condensable gas discharge port is either directly discharged to the atmosphere or collected in a storage tank. The storage deuterium-rich water outlet is used to discharge the enriched deuterium water. The water ring vacuum pump draws in the non-condensable gas generated in the flash tank, mixes it with liquid, and sends it to the alkali buffer tank through the pump's gas-liquid mixing outlet. The non-condensable gas is finally discharged through the buffer tank's non-condensable gas discharge port, realizing the gas phase intake and exhaust of the water ring vacuum pump and maintaining the negative pressure environment inside the flash tank.

[0017] More specifically, in this invention, the alkali buffer tank has a gas-liquid mixing inlet, a non-condensable gas outlet, and an alkali outlet. The gas-liquid mixing inlet is connected to the gas-liquid mixing outlet of the water ring vacuum pump, and the alkali outlet is connected to the alkali return inlet of the water ring vacuum pump via a first branch, forming an alkali circulation loop. A first valve is provided on the first branch. The non-condensable gas outlet directly discharges into the atmosphere or is collected in a storage tank.

[0018] Furthermore, a second branch is connected to the alkali outlet of the buffer tank, and a second valve is installed on the second branch. The second branch is connected to the alkaline electrolysis unit and is used to send the alkali solution to the alkaline electrolysis unit for circulation electrolysis. Specifically, it is connected to the cathode side of the alkaline electrolysis cell in the alkaline electrolysis unit, and a second circulation pump is installed on the connecting pipe.

[0019] The present invention also provides an online extraction and enrichment device for heavy water using an alkaline electrolytic cell, comprising an online extraction and enrichment unit for heavy water using an alkaline electrolytic cell as described above, and further comprising an alkaline electrolysis unit and a separation and circulation unit. The alkaline electrolysis unit generates a gas-liquid mixture through electrolysis and transports it to the separation and circulation unit. The separation and circulation unit sends the separated alkaline solution to the deuterium-rich water extraction unit for online extraction of deuterium-rich water.

[0020] Furthermore, in practice, the alkaline electrolysis unit includes an alkaline electrolytic cell, which has an anode side and a cathode side; the separation and circulation unit includes an anode gas-liquid separator, a cathode gas-liquid separator, and a fuel cell; The gas-liquid inlet of the anode gas-liquid separator is connected to the anode side, the gas outlet of the anode gas-liquid separator is connected to the positive electrode of the fuel cell, and the liquid outlet of the anode gas-liquid separator is returned to the anode side of the alkaline electrolyzer through a circulation pump. The gas-liquid inlet of the cathode gas-liquid separator is connected to the cathode side, and the gas outlet of the cathode gas-liquid separator is connected to the negative electrode of the fuel cell. Specifically, the gas outlet of the cathode gas-liquid separator is first connected to condenser one, and then connected to the negative electrode of the battery. A return pipe is also provided between condenser one and the cathode gas-liquid separator. The liquid outlet of the cathode gas-liquid separator is connected to the deuterium-rich water extraction unit, supplying the alkaline solution to be treated to the deuterium-rich water extraction unit. Furthermore, the fuel cell exhaust outlet is also connected to condenser three, where low-deuterium water is obtained through condensation. Further, in practice, a deuterium-rich water replenisher is also provided, which is used to transport deuterium-rich water to the cathode side of the alkaline electrolyzer for electrolysis. A flow control component, such as a pump, can be installed on the delivery pipe of the deuterium-rich water replenisher to control the flow rate.

[0021] In this invention, the gas (mainly oxygen) separated by the anode gas-liquid separator enters the positive electrode of the fuel cell, while the gas (mainly deuterium-lean hydrogen) separated by the cathode gas-liquid separator enters the negative electrode. The oxygen and deuterium-lean hydrogen react in the fuel cell to generate deuterium-free water, simultaneously producing electricity. This deuterium-free water can be directly collected as a product or returned to the previous alkaline electrolyzer for further electrolysis. Furthermore, the positive electrode of the fuel cell can also be selected by introducing additional oxygen (pure oxygen or oxygen-containing gas, such as air) to ensure a hydrogen / oxygen molar ratio of 2:(1.3~1.5), guaranteeing complete combustion of the gas. In summary, the electricity generated by the fuel cell can be used to charge the energy storage power supply of the electrolysis system, thereby completing the energy conversion and recycling of high-temperature hydrogen / deuterium.

[0022] Furthermore, the alkaline electrolysis unit has a refrigeration module, and condensers three and four share the same refrigeration module with the alkaline electrolysis unit; or / and, the temperature of condensers three and four is controlled between 10-25℃. In practice, it is controlled at 10℃, 15℃, 20℃, 25℃, etc.

[0023] It should be noted that in practice, the cooling system of industrial alkaline electrolyzers typically reserves 10% to 20% of spare cooling capacity to cope with fluctuations in operating conditions. This invention fully utilizes the reserved cooling margin in the design of the alkaline electrolyzer cooling system. The cooling load required for the deuterium-enriched water extraction process accounts for only 15% to 20% of the total heat dissipation load of the alkaline electrolyzer, which is entirely within the cooling margin range and will not adversely affect the operating temperature control of the alkaline electrolyzer itself. By sharing the refrigeration module built into the alkaline electrolysis unit itself, specifically by using a cooling water circulation system, the cooling water in the cooling water circulation loop of the alkaline electrolyzer is diverted into the refrigerant channels of condenser three and condenser four for heat exchange, and then returned to the cooling water circulation system of the alkaline electrolyzer, realizing the cyclic supply of cooling capacity. There is no need to introduce external refrigerant or configure additional refrigeration units. This design further simplifies the system structure, reduces equipment investment, avoids additional cooling energy consumption, and significantly improves the energy utilization efficiency and economy of the entire heavy water enrichment system.

[0024] This invention also provides an online extraction and enrichment device for heavy water using an alkaline electrolytic cell, comprising at least two stages of the online extraction and enrichment device for heavy water using an alkaline electrolytic cell as described above; wherein the enriched deuterium water after treatment by the previous stage deuterium-rich water extraction unit is connected to the next stage alkaline electrolysis unit for step-by-step electrolysis; and the low-deuterium water after treatment by the next stage separation and circulation unit is connected to the previous stage alkaline electrolysis unit for further electrolysis.

[0025] More specifically, the deuterium-enriched water stored in the deuterium-enriched water storage device in the previous stage deuterium-enriched water extraction unit is connected to the cathode side of the alkaline electrolyzer in the next stage alkaline electrolysis unit; the deuterium-poor water produced after being treated by the fuel cell in the next stage separation and circulation unit is connected to the cathode side of the alkaline electrolyzer in the previous stage alkaline electrolysis unit.

[0026] This invention organically integrates an alkaline electrolysis unit, a deuterium-rich water extraction unit, and a separation and circulation unit to form a closed-loop circulation device. The deuterium-rich water after flash evaporation separation can be fed into the next stage of the alkaline electrolysis cell, while the deuterium-poor water produced by the fuel cell can be returned to the previous stage of the alkaline electrolysis cell, achieving multi-stage series connection and significantly improving the final deuteration degree of the deuterium-rich water. The equipment requires no external water replenishment or frequent manual intervention during operation, exhibits high system integration, stable operation, and is suitable for multi-stage series scale-up, demonstrating good continuous operation and prospects for industrial scale-up.

[0027] This invention also provides an online extraction and enrichment system for heavy water using an alkaline electrolyzer, comprising a pretreatment module and a deep treatment module used in series, wherein the deep treatment module includes a proton exchange membrane electrolyzer. The pretreatment module uses the alkaline electrolytic cell online extraction and enrichment device for heavy water as described above; or uses the alkaline electrolytic cell online extraction and enrichment device as described above.

[0028] This invention also provides a method for online extraction and enrichment of heavy water using an alkaline electrolyzer, employing the alkaline electrolyzer online extraction and enrichment unit described above. The process is as follows: S1. Water electrolysis is performed using an alkaline electrolysis unit; S2. The gas-liquid mixture generated by the alkaline electrolysis unit is processed by the separation and circulation unit, and the separated alkaline solution is sent to the deuterium-rich water extraction unit for online extraction of deuterium-rich water.

[0029] More specifically, the gas-liquid mixture generated on the anode side of the alkaline electrolysis unit is sent to the anode gas-liquid separator in the separation circulation unit for processing, and the separated alkaline solution is returned to the anode side; the gas-liquid mixture generated on the cathode side of the alkaline electrolysis unit is sent to the cathode gas-liquid separator in the separation circulation unit for processing, and the separated alkaline solution is sent to the deuterium-rich water extraction unit for online extraction of deuterium-rich water.

[0030] In this invention, during the deuterium-rich water extraction unit process, the water ring vacuum pump adopts a staged working fluid supply mode, including: Initial vacuum establishment stage: Using the alkali solution pre-stored in the alkali solution buffer tank as the working fluid, the alkali solution is pre-circulated in a closed loop through the alkali solution circulation loop between the alkali solution buffer tank and the water ring vacuum pump to establish the required negative pressure environment inside the flash tank. Continuous operation phase: The working fluid is switched to continuous alkaline solution from the flash tank. This alkaline solution is mixed with non-condensable gas from the deuterium-rich water storage tank by the water ring vacuum pump and then sent to the alkaline buffer tank. After gas-liquid separation, the working alkaline solution flows back from the alkaline buffer tank to the cathode side of the alkaline electrolysis unit and no longer flows directly back to the water ring vacuum pump.

[0031] Specifically, in practical operation, through the coordinated setup of the first and second branches, both the first and second valves are automatically controlled valves, and they are linked and switched according to the vacuum signal inside the flash tank, enabling the switching of different operating states of the water ring vacuum pump. Specifically, the first operating state is the initial vacuum establishment stage, and the second operating state is the continuous operation stage.

[0032] In the first working state, the first valve is open and the second valve is closed. The water ring vacuum pump draws the alkali solution pre-stored in the alkali solution buffer tank through the first branch and delivers it to the alkali solution return inlet of the water ring vacuum pump through the alkali solution outlet of the buffer tank, forming a working alkali solution circulation loop. At the same time, the water ring vacuum pump draws non-condensable gas through the storage non-condensable gas outlet of the deuterium-rich water storage tank to evacuate the flash tank until the interior of the flash tank reaches a preset negative pressure, i.e., a negative pressure environment of -88~-82 kPa. In practice, it can be controlled as -88 kPa, -86 kPa, -85 kPa, -82 kPa, etc.

[0033] In the second working state, after the flash tank reaches the preset negative pressure, the first valve closes and the second valve opens. The alkaline solution in the alkaline buffer tank is transported to the second circulation pump through the second branch, and then returns to the cathode side of the alkaline electrolysis cell to form a circulation loop of the working alkaline solution. At the same time, the water ring vacuum pump continues to work to continuously extract non-condensable gas and maintain the negative pressure environment inside the flash tank.

[0034] This invention employs a staged working fluid supply for the water ring vacuum pump, effectively preventing the loss of high-value deuterium-containing water vapor. The working fluid of the water ring vacuum pump is a flash-concentrated alkaline solution, avoiding the risk of uncondensed deuterium-containing water vapor being absorbed or carried away by the working fluid when using ordinary water or external circulating water, thus effectively preventing the loss of high-value deuterium-rich water vapor. Simultaneously, the deuterium component in the alkaline solution remains in the alkaline solution circulation system and is ultimately returned to the alkaline electrolyzer along with the concentrated alkaline solution to continue participating in electrolytic enrichment, maximizing the recovery of deuterium resources. Compared to conventional designs that use pure water or circulating water as the working fluid, this invention uses concentrated alkali solution within the system instead of pure water as the working fluid. By utilizing the low solubility of water vapor in alkali solution, the water ring vacuum pump is equipped with the function of a "selective sealing medium," thus avoiding the risk of uncondensed, high-value deuterium-containing water vapor being absorbed by the working fluid or being carried away and discharged. At the same time, the water ring vacuum pump significantly lowers the boiling point of water by creating a negative pressure environment, allowing the electrolytic heat carried by the alkali solution to be released and converted into flash evaporation driving force. At this point, the role of the working fluid changes from a passive "power transmission medium" to an active "energy carrier."

[0035] This invention employs a phased supply strategy. In the initial vacuum establishment phase, concentrated alkali pre-circulates within an alkali buffer tank to rapidly establish the negative pressure required for flash evaporation. During continuous operation, the system switches to continuous concentrated alkali from condenser three. This alkali is mixed with non-condensable gases via a water ring vacuum pump and then fed into the alkali buffer tank for gas-liquid separation. The working alkali is then transported from the bottom of the buffer tank back to the cathode side of the alkaline electrolyzer, instead of directly returning to the water ring vacuum pump. This ensures the working fluid remains in a closed-loop circulation within the main process, with the deuterium component fully retained in the alkali system and ultimately returned to the electrolyzer. This avoids resource waste caused by working fluid discharge in conventional open-loop systems. Consequently, the water ring vacuum pump is transformed into a multifunctional integrated unit combining vacuum maintenance, flash evaporation drive, and minimal deuterium resource recovery, achieving the integrated goal of low-energy system operation and maximized deuterium resource recovery.

[0036] Furthermore, the volume of alkali solution pre-stored in the alkali buffer tank is 1 / 3 to 2 / 3 of the total volume of the alkali buffer tank. In practice, it can be specifically controlled to be 1 / 3, 1 / 2, 2 / 3, etc.

[0037] Furthermore, when the water ring vacuum pump is in continuous operation, the feed rate of the alkali buffer tank to the alkaline electrolysis unit is 0.8-5200 L / h, such as 0.8L / h, 10 L / h, 100 L / h, 500 L / h, 1000 L / h, 3000 L / h, 5200 L / h in practice; the rate at which the alkali buffer tank discharges non-condensable gas through the non-condensable gas discharge port is 0.3-1850 NL / h, such as 0.3 NL / h, 10 NL / h, 100 NL / h, 500 NL / h, 1000 NL / h, 1500 NL / h, 1850 NL / h in practice.

[0038] Furthermore, the flash temperature range of the flash tank is 60~65 ℃, and in practice it is 60 ℃, 62 ℃, 64 ℃, 65 ℃, etc.

[0039] Furthermore, the electrolysis temperature of the alkaline electrolytic cell in the alkaline electrolysis unit is 55–90℃, and in practice, it is 55℃, 60℃, 80℃, 90℃, etc.

[0040] Furthermore, the feed rate of the liquid delivered from the separation and circulation unit to the flash tank is 1.0-5500 L / h, and in practice, it is 1.0 L / h, 10 L / h, 100 L / h, 500 L / h, 1000 L / h, 3000 L / h, 5500 L / h, etc.

[0041] Furthermore, a condenser is installed between the liquid outlet of the flash tank and the alkali inlet of the water ring vacuum pump. The feed rate of the liquid from the condenser to the water ring vacuum pump is 0.8-5200 L / h, such as 0.8L / h, 10 L / h, 100 L / h, 500 L / h, 1000 L / h, 3000 L / h, 5200 L / h, etc. in practice.

[0042] Furthermore, a condenser four is installed between the outlet of the flash tank and the deuterium-rich water storage tank. The feed rate of the liquid from the condenser four to the deuterium-rich water storage tank is 0.05-270 kg / h, such as 0.05 kg / h, 1.0 kg / h, 10 kg / h, 50 kg / h, 100 kg / h, 180 kg / h, 270 kg / h, etc. in practice.

[0043] In practice, when a multi-stage series enrichment system is used, there is a causal control chain between the operating parameters of each stage of the equipment. The final extraction rate of enriched deuterium water is limited by the production rate of deuterium-enriched water vapor in the flash tank. The production rate of deuterium-enriched water vapor in the flash tank is determined by the saturated vapor pressure above the surface of the alkali solution at that temperature. The level of the saturated vapor pressure is controlled by the absolute pressure inside the flash tank, i.e., the vacuum degree. The vacuum degree of the flash tank depends on the actual operating conditions of the water ring vacuum pump.

[0044] In summary, this invention, through the aforementioned parameter linkage mechanism, enables a multi-stage series system where, when deuterium-rich water from the previous stage is used as feed for the next stage, the vacuum level of the next-stage flash tank can be preset to the required level simply by adjusting the operating conditions of the next-stage water ring vacuum pump. This automatically matches the deuterium-rich water extraction rate of that stage with the supply rate of the previous stage, eliminating the need for complex real-time flow control. This parameter linkage mechanism ensures stable material flow between stages and long-term continuous stable operation of the system without the need for additional complex flow control instruments. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the heavy water equipment in this invention; Figure 2 This is a schematic diagram of the deuterium-rich water extraction unit in this invention; Figure 3 This is a schematic diagram of the system structure of the multi-stage heavy water equipment connected in series in this invention.

[0046] Explanation of the labels in the diagram: 100. Alkaline electrolysis unit; 110. Alkaline electrolytic cell; 111. Anode side; 112. Cathode side; 300. Separation and circulation unit; 310. Anode gas-liquid separator; 320. Cathode gas-liquid separator; 330. Fuel cell; 331. Battery negative electrode; 332. Battery positive electrode; 340. Condenser I; 350. Condenser II; 360. Circulation pump I; 410. Deuterium-rich water supply device; 411. Flow component one.

[0047] 200. Deuterium-rich water extraction unit; 210. Flash tank; 211. Liquid inlet of the tank; 212. Gas outlet of the tank; 213. Liquid outlet of the tank; 220. Condenser 3; 250. Circulation Pump 2; 260. Condenser 4; 230. Water ring vacuum pump; 231. Alkali inlet of pump; 232. Gas-liquid mixing outlet of pump; 233. Alkali reflux inlet of pump; 234. First branch; 240. Alkali buffer tank; 241. Gas-liquid mixing inlet of buffer tank; 242. Non-condensable gas outlet of buffer tank; 243. Alkali outlet of buffer tank; 244. Second branch; 270. Deuterium-rich water storage container; 271. Deuterium-rich water inlet of storage container; 272. Non-condensable gas outlet of storage container; 273. Non-condensable gas discharge port of storage container; 274. Deuterium-rich water outlet of storage container. Detailed Implementation

[0048] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0049] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., 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 the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] The inventors have dedicated themselves to the technical research of heavy water extraction. Their preliminary research results were disclosed in patent application CN121988166A, which provided an alkaline electrolytic cell coupled with an online heavy water extraction and enrichment device, aiming to improve the effective extraction of heavy water. However, in practice, it was found that this solution required an additional heat source, such as electric heating or steam, to maintain the evaporation temperature, resulting in high system energy consumption; increased equipment investment and operating costs; and low overall energy utilization efficiency, which is not conducive to energy saving and consumption reduction in large-scale industrial applications. The inventors further researched and proposed the alkaline electrolytic cell online heavy water extraction and enrichment unit of this embodiment.

[0051] The present invention will be further described below with reference to embodiments.

[0052] Example This embodiment of the invention provides an online heavy water extraction and enrichment unit using an alkaline electrolyzer, specifically including a deuterium-rich water extraction unit 200. The invention also provides an online heavy water extraction and enrichment device using an alkaline electrolyzer, comprising an alkaline electrolysis unit 100, a deuterium-rich water extraction unit 200, and a separation and circulation unit 300. The alkaline electrolysis unit 100 generates a gas-liquid mixture through electrolysis and transports it to the separation and circulation unit 300. The separation and circulation unit 300 sends the separated alkaline solution to the deuterium-rich water extraction unit 200 for online extraction of deuterium-rich water. Specifically, the alkaline electrolysis unit 100 includes an alkaline electrolyzer 110, which has an anode side 111 and a cathode side 112. The separation and circulation unit 300 includes an anode gas-liquid separator 310, a cathode gas-liquid separator 320, and a fuel cell 330.

[0053] The gas-liquid inlet of the anode gas-liquid separator 310 is connected to the anode side 111, and the gas outlet of the anode gas-liquid separator 310 is connected to the positive electrode 332 of the fuel cell 330. The liquid outlet of the anode gas-liquid separator 310 is connected to the anode side 111 via a circulation pump 360. The gas-liquid inlet of the cathode gas-liquid separator 320 is connected to the cathode side 112, and the gas outlet of the cathode gas-liquid separator 320 is connected to the negative electrode 331 of the fuel cell 330 via a condenser 340. The liquid outlet of the cathode gas-liquid separator 320 is connected to the deuterium-rich water extraction unit 200, and the alkaline solution to be treated is supplied to the deuterium-rich water extraction unit 200.

[0054] The deuterium-rich water extraction unit 200 includes a flash tank 210, a water ring vacuum pump 230, an alkali buffer tank 240, and a deuterium-rich water storage tank 270. The liquid inlet 211 of the flash tank 210 is connected to the liquid outlet of the cathode gas-liquid separator 320 to receive alkali. The liquid outlet 213 of the flash tank 210 is preferably connected to the alkali inlet 231 of the water ring vacuum pump 230 via a condenser 320. The gas outlet 212 of the flash tank 210 is preferably connected to the deuterium-rich water inlet 271 of the deuterium-rich water storage tank 270 via a condenser 4260. The non-condensable gas outlet 272 of the deuterium-rich water storage tank 270 is connected to the alkali inlet 231 of the pump. The non-condensable gas outlet 273 of the deuterium-rich water storage tank 270 is connected to the atmosphere for exhaust. The deuterium-rich water outlet 274 of the deuterium-rich water storage tank 270 discharges the enriched deuterium water.

[0055] The pump gas-liquid mixing outlet 232 of the water ring vacuum pump 230 is connected to the buffer tank gas-liquid mixing inlet 241 of the alkali buffer tank 240. The buffer tank non-condensable gas discharge outlet 242 of the alkali buffer tank 240 is connected to the atmosphere for exhaust. The buffer tank alkali outlet 243 of the alkali buffer tank 240 is connected to the pump alkali return inlet 233 of the water ring vacuum pump 230 through a first branch 234, and a first valve is provided on the first branch 234. The buffer tank alkali outlet 243 is connected to the cathode side 112 of the alkaline electrolysis cell 110 through a second branch 244 and a second circulation pump 250, and a second valve is provided on the second branch 244. The water ring vacuum pump 230 continuously draws a vacuum into the flash tank 210, maintaining a negative pressure state of -88 to -82 kPa inside the flash tank 210.

[0056] The preferred alkaline electrolysis unit 100 has a refrigeration module. The condenser 3 220 and the condenser 4 260 are respectively provided with refrigerant channels that are connected to the refrigeration module of the alkaline electrolysis unit 100 and share the same set of refrigeration modules for cooling capacity circulation supply. The temperature control range of the condenser 3 220 and the condenser 4 260 is 10-25℃.

[0057] This embodiment also provides a method for online extraction and enrichment of heavy water using an alkaline electrolyzer, employing the alkaline electrolyzer online extraction and enrichment device described above. The process is as follows: S1. Water electrolysis is performed using the alkaline electrolysis unit 100; S2. The gas-liquid mixture generated by the alkaline electrolysis unit 100 is processed by the separation and circulation unit 300, and the separated alkaline solution is sent to the deuterium-rich water extraction unit 200 for online extraction of deuterium-rich water.

[0058] In the deuterium-rich water extraction unit 200 process, the water ring vacuum pump 230 adopts a staged working fluid supply mode, including: Initial vacuum establishment stage: Using the alkaline solution pre-stored in the alkaline solution buffer tank 240 as the working fluid, the alkaline solution is pre-circulated in a closed loop through the alkaline solution circulation loop between the alkaline solution buffer tank 240 and the water ring vacuum pump 230 to establish the required negative pressure environment inside the flash tank 210. Continuous operation phase: The working fluid is switched to continuous alkaline solution from flash tank 210. This alkaline solution is mixed with non-condensable gas from deuterium-rich water storage tank 270 by water ring vacuum pump 230 and then sent to alkaline solution buffer tank 240. After gas-liquid separation, the working alkaline solution flows back from alkaline solution buffer tank 240 to the cathode side 112 in alkaline electrolysis unit 100 and no longer flows directly back to water ring vacuum pump 230.

[0059] Furthermore, in practice, several process parameters are preferably controlled, including: the volume of alkali solution pre-stored in the alkali buffer tank 240 is 1 / 3 to 2 / 3 of the total volume of the alkali buffer tank 240; the flash temperature range of the flash tank 210 is 60~65 ℃; the feed rate of the liquid from the separation circulation unit 300 to the flash tank 210 is 1.0-5500 L / h; a condenser 3 220 is installed between the liquid outlet of the flash tank 210 and the alkali solution inlet 231 of the water ring vacuum pump 230, and the feed rate of the liquid from the condenser 3 220 to the water ring vacuum pump 230 is 0.8-5200 L / h; and the feed rate of the condenser 4 260 to the deuterium-rich water storage tank 270 is 0.05-270 kg / h. When the water ring vacuum pump 230 is in continuous operation, the feed rate of the alkali buffer tank 240 to the alkaline electrolysis unit 100 is 0.8-5200 L / h, and the rate at which the alkali buffer tank 240 discharges non-condensable gas through the buffer tank non-condensable gas discharge port 242 is 0.3-1850 NL / h.

[0060] This embodiment also provides an online heavy water extraction and enrichment device using an alkaline electrolyzer, comprising at least two stages of the online heavy water extraction and enrichment device described above. The deuterium-rich water processed by the previous stage deuterium-rich water extraction unit 200 is connected to the next stage alkaline electrolysis unit 100; the deuterium-poor water processed by the next stage separation and circulation unit 300 is connected to the previous stage alkaline electrolysis unit 100. Specifically, the deuterium-rich water stored in the deuterium-rich water storage device 270 in the previous stage deuterium-rich water extraction unit 200 is connected to the cathode side 112 of the alkaline electrolysis cell 110 in the next stage alkaline electrolysis unit 100; the deuterium-poor water generated after treatment by the fuel cell 330 in the next stage separation and circulation unit 300 is connected to the cathode side 112 of the alkaline electrolysis cell 110 in the previous stage alkaline electrolysis unit 100.

[0061] This embodiment also provides an online heavy water extraction and enrichment system using an alkaline electrolyzer, including a pretreatment module and a deep treatment module used in series. The deep treatment module includes a proton exchange membrane electrolyzer. The pretreatment module uses the online heavy water extraction and enrichment device using an alkaline electrolyzer as described above; or it uses the online heavy water extraction and enrichment equipment using an alkaline electrolyzer as described above.

[0062] The following is a detailed explanation of the method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to the present invention, using specific practical examples.

[0063] Implementation Case 1 1. Initial vacuum establishment phase: At 50 Nm 3Before starting the alkaline electrolysis unit 100, the alkaline buffer tank 240 is pre-stored with a sufficient amount of 150 kg of concentrated alkaline solution, specifically 25 wt% KOH, which occupies 1 / 3 of the total volume of the alkaline buffer tank 240. Close the second valve on the second branch 244 and open the first valve on the first branch 234. The water ring vacuum pump 230 is started. The alkali solution in the alkali buffer tank 240 flows out through the alkali solution outlet 243 of the buffer tank. It circulates at a rate of 307.9 L / h and enters the water ring vacuum pump 230 through the first branch 234. The alkali solution then returns to the alkali buffer tank 240 as the working alkali solution entering the water ring vacuum pump 230. After completing the internal circulation of the water ring vacuum pump 230, it returns to the alkali buffer tank 240 through the pump gas-liquid mixing outlet 232, forming a circulation loop for the working alkali solution. The circulation flow rate is 307.9 L / h. The water ring vacuum pump 230 continuously evacuates the flash tank 210 until the vacuum degree inside the flash tank 210 reaches the preset value of -88 kPa.

[0064] 2. Continuous operation phase: Once the vacuum level inside the flash tank 210 reaches the preset value, the first valve is closed and the second valve is opened, and the system switches to the continuous operation stage.

[0065] 2.1 Water electrolysis process: Start-up 50 Nm 3 In the alkaline electrolysis unit 100, the 25wt% KOH electrolyte in the alkaline electrolysis cell 110, with a deuterium content of 380 ppm, is decomposed into deuterium-deficient hydrogen and oxygen at an operating temperature of 88℃ and a system operating pressure of 1.6 MPa. This results in a high-temperature gas-liquid mixture of deuterium-deficient hydrogen and alkaline solution on the cathode side 112, and a high-temperature gas-liquid mixture of oxygen and alkaline solution on the anode side 111, with a current density of 3000 mA·cm⁻¹. -2 .

[0066] 2.2 Alkali solution circulation process: The high-temperature gas-liquid mixture on the anode side 111 is fed to the anode gas-liquid separator 310 for the separation of oxygen and alkali solution. The alkali solution separated by the anode gas-liquid separator 310 is returned to the alkali solution inlet on the anode side 111. The high-temperature gas-liquid mixture on the cathode side 112 is fed to the cathode gas-liquid separator 320 for the separation of deuterium-deficient hydrogen gas and alkali solution. The alkali solution separated at the bottom of the cathode gas-liquid separator 320 flows directly into the flash tank 210 for online extraction of deuterium-rich water. The concentrated alkali solution separated from the flash tank 210 is cooled by the condenser 220 and then... The gas-liquid mixing outlet 232 of the water ring vacuum pump 230 delivers the solution to the gas-liquid mixing inlet 241 of the alkaline buffer tank 240. Then, through the second branch 244, the second circulation pump 250 delivers the concentrated alkaline solution to the cathode side 112 of the alkaline electrolyzer 110, realizing the separate circulation and recovery of alkaline solutions on the anode side 111 and the cathode side 112. Simultaneously, using the second flow component 411, such as a circulation pump, the deuterium-rich water produced by the online extraction and enrichment unit of the previous alkaline electrolyzer 110 is controlled to replenish the alkaline buffer tank 240 of this stage at a flow rate of 14.5 kg / h. The deuterium content of the low-deuterium hydrogen gas discharged from the condenser 340 is 147.2 ppm. Based on the flow rate of the circulation pump 360, the flow rate of the alkaline solution circulation on the anode side 111 of the alkaline electrolysis unit 100 is 3500 L / h.

[0067] 3. Online extraction of deuterium-rich water: The alkaline solution separated from the bottom of the cathode gas-liquid separator 320 is fed into the tank liquid inlet 211 at the top of the flash tank 210 at a flow rate of 320L / h by a circulating pump. In this embodiment, the water ring vacuum pump 230 is used to maintain the pressure inside the flash tank 210 at a vacuum degree of -88kPa. Utilizing the heat of the high-temperature alkaline solution itself from the cathode side 112 of the alkaline electrolysis cell, the deuterium-rich water in the alkaline solution is rapidly flash-separated under negative pressure conditions.

[0068] The high-temperature deuterium-rich water vapor generated by flash evaporation enters condenser 260 through the gas outlet 212 at the top of flash tank 210. The cooling source for condenser 260 is the refrigeration module integrated into the alkaline electrolytic cell 110, with a temperature control range of 15~20℃. The deuterium-rich water vapor is collected in a deuterium-rich water storage tank 270 after condensation. The feed rate from the liquid outlet of condenser 260 to the deuterium-rich water storage tank 270 is 14.5 kg / h.

[0069] The concentrated alkali solution discharged from the bottom of flash tank 210 enters condenser 220 at a flow rate of 307.9 L / h, with a temperature control range of 15–20°C. The concentrated alkali solution from condenser 220 is pumped to alkali buffer tank 240 via the alkali inlet 231 of water ring vacuum pump 230 and the gas-liquid mixing outlet 232. It then returns to the cathode side 112 of alkaline electrolytic cell 110 via the second branch 244. Simultaneously, water ring vacuum pump 230 extracts non-condensable gas through the non-condensable gas outlet 272 of deuterium-rich water storage tank 270. This non-condensable gas mainly contains a small amount of deuterium-poor hydrogen and oxygen, with a flow rate of 108 Nm³ / h. After gas-liquid mixing, it is sent to alkali buffer tank 240. The non-condensable gas is finally discharged from the system through the non-condensable gas discharge outlet 242 of alkali buffer tank 240.

[0070] After 72 hours of continuous operation, the deuterium content in the deuterium-rich water condensed in the deuterium-rich water storage tank 270 increased to 515 ppm, and the outflow rate stabilized at 14.5 kg / h.

[0071] 4. Fuel cell process: High-temperature deuterium-deficient hydrogen separated from the top of the cathode gas-liquid separator 320 enters the negative electrode inlet 331 of the fuel cell 330, while high-temperature oxygen separated from the top of the anode gas-liquid separator 310 enters the positive electrode inlet 332 of the fuel cell 330. The fuel cell 330 generates deuterium-deficient water and produces electricity simultaneously. The deuterium-deficient water can be directly collected as a product or returned to the alkaline electrolyzer 110 of the previous alkaline electrolyzer for online extraction and enrichment of heavy water for further electrolysis. The electricity generated by the fuel cell 330 can be used to charge the energy storage power supply of the electrolysis system, thereby completing the energy conversion and recycling of high-temperature hydrogen / deuterium. In some embodiments, the exhaust outlet of the fuel cell 330 is connected to condenser 2 350, and the deuterium-deficient water is obtained by condensation in condenser 350. After 72 hours of continuous operation, the deuterium content in the deuterium-deficient water returned to the upper-level electrolysis enrichment unit is 147.2 ppm, and the water collection flow rate is stable at 40.2 kg / h.

[0072] Implementation Case 2 This embodiment provides a method for continuous online extraction and enrichment of high-concentration heavy water by using multiple stages of alkaline electrolytic cells for online extraction and enrichment of heavy water. The operation process of this embodiment is based on Implementation Case 1 by adding liquid circuit connection and reflux between two adjacent alkaline electrolytic cells for online extraction and enrichment of heavy water.

[0073] The purpose of the method in this embodiment is to increase the deuteration degree of heavy water. Specifically, in terms of operation: The deuterium-rich water obtained from the previous process is fed into the cathode side 112 of the alkaline electrolyzer 110 in the next process for water electrolysis; the deuterium-poor water generated by the reaction of the fuel cell 330 in the next process is fed into the cathode side 112 of the alkaline electrolyzer 110 in the previous process for water electrolysis.

[0074] Each alkaline electrolyzer 110 connected in series is matched with a corresponding specification based on the hydrogen production. For example, the first stage is selected with a capacity of 1000 Nm based on the hydrogen production. 3 / h alkaline electrolytic cell 110, the current density during electrolysis is 3000mA·cm -2 Simultaneously, the liquid inlet rate of the cathode side 112 is controlled. The liquid inlet rate and deuteration degree of the cathode side 112 are shown in Table 1 below. After running for 72 hours, the other structural and operating parameter information for each alkaline electrolytic cell 110 connected in series are the same as in Implementation Case 1. The deuteration degree data are shown in Table 1 below.

[0075] Table 1. Deuteration degree of deuterated water obtained with different series series.

[0076] As shown in Table 1, even with the same 72-hour operation, the deuteration degree of deuterated water can be effectively improved by using a multi-stage alkaline electrolytic cell for online extraction and enrichment of heavy water.

[0077] Implementation Case 3 In this embodiment, the alkaline electrolyzer used for online extraction and enrichment of heavy water, as described above, is connected in two stages as a pretreatment system, and then used in conjunction with a proton exchange membrane (PEM) electrolyzer to further increase the heavy water concentration. The specific steps are as follows: The difference between Implementation Case 3 and Implementation Case 2 lies in the following: the alkaline electrolytic cell online extraction and enrichment equipment for heavy water is connected in series with a PEM electrolytic cell commonly used in the electrolysis field. That is, after the two-stage alkaline electrolytic cell online extraction and enrichment device for heavy water is connected in series, the discharged alkaline solution is distilled to produce pure water, which is then fed into the PEM electrolytic cell for further electrolysis, achieving a continuous increase in the deuteration degree of the heavy water. The specifications of each alkaline electrolytic cell (110) connected in series are also matched according to the hydrogen production, and the current density during electrolysis is 10000 A·m. -2 Meanwhile, the deuteration rate of the liquid entering the cathode side 112 is shown in Table 2 below. After running for 72 hours, the other operating parameters are the same as in Implementation Case 2, and the deuteration data are shown in Table 2 below.

[0078] Table 2. Deuteration degree of deuterated water obtained by ALK-PEM with different series order.

[0079] Explanation, in the table: The series system PEM, with a series stage number of 3, indicates that ALK and PEM are used together. Specifically, the series stage number of ALK is 2, and the series stage number of PEM is 1. The series system PEM, with a series stage number of 5, indicates that ALK and PEM are used together. Specifically, the series stage number of ALK is 2 and the series stage number of PEM is 3. The series system PEM, with a series stage number of 10, indicates that ALK and PEM are used together. Specifically, the series stage number of ALK is 2, and the series stage number of PEM is 8. The series system PEM, with a series stage number of 15, indicates that ALK and PEM are used together. Specifically, the series stage number of ALK is 2, and the series stage number of PEM is 13. The series system PEM has 25 series stages, indicating that ALK and PEM are used together. Specifically, ALK has 2 series stages and PEM has 23 series stages. As shown in Table 2, the alkaline electrolyzer for online extraction and enrichment of heavy water, or its multi-stage combination, can serve as a pretreatment system. When used in conjunction with a proton exchange membrane (PEM) electrolyzer, it can further enhance the concentration of heavy water.

[0080] The present invention and its embodiments have been described above illustratively. This description is not restrictive and is merely one embodiment of the present invention, and is not actually limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. An online heavy water extraction and enrichment unit in an alkaline electrolytic cell, comprising a deuterium-rich water extraction unit (200), characterized in that: The deuterium-rich water extraction unit (200) includes a flash tank (210), a water ring vacuum pump (230), an alkali buffer tank (240), and a deuterium-rich water storage device (270). The flash tank (210) has a tank liquid inlet (211) for receiving the alkali solution after electrolytic separation. The flash tank (210) has a tank liquid outlet (213) connected to the pump alkali inlet (231) of the water ring vacuum pump (230). The water ring vacuum pump (230) delivers the alkali solution to the alkali buffer tank (240), and an alkali solution circulation loop is formed between the water ring vacuum pump (230) and the alkali buffer tank (240). The flash tank (210) has a tank gas outlet (212) connected to a deuterium-rich water storage tank (270), and the deuterium-rich water storage tank (270) has a storage non-condensable gas outlet (272) connected to the pump alkali inlet (231) of the water ring vacuum pump (230).

2. The alkaline electrolytic cell online extraction and enrichment unit for heavy water according to claim 1, characterized in that: The water ring vacuum pump (230) continuously draws a vacuum into the flash tank (210), maintaining a negative pressure state of -88~-82 kPa inside the flash tank (210).

3. The alkaline electrolytic cell online extraction and enrichment unit for heavy water according to claim 1, characterized in that: A condenser three (220) is provided between the liquid outlet (213) of the flash tank (210) and the alkali inlet (231) of the water ring vacuum pump (230). The alkali liquid evaporated in the flash tank (210) is condensed by the condenser three (220) and enters the water ring vacuum pump (230), and is transported to the alkali buffer tank (240). Or / and, a condenser four (260) is provided between the tank gas outlet (212) of the flash tank (210) and the deuterium-rich water storage (270). The gas evaporated in the flash tank (210) is condensed by the condenser four (260) and then enters the deuterium-rich water storage (270).

4. The alkaline electrolytic cell online extraction and enrichment unit for heavy water according to claim 1, characterized in that: The alkali buffer tank (240) has a buffer tank gas-liquid mixing inlet (241) and a buffer tank alkali outlet (243). The buffer tank gas-liquid mixing inlet (241) is connected to the pump gas-liquid mixing outlet (232) of the water ring vacuum pump (230). The buffer tank alkali outlet (243) is connected to the pump alkali return inlet (233) of the water ring vacuum pump (230) through the first branch (234) to form an alkali circulation loop. A first valve is provided on the first branch (234).

5. The alkaline electrolytic cell online extraction and enrichment unit for heavy water according to claim 4, characterized in that: The buffer tank alkaline outlet (243) is also connected to a second branch (244), which is equipped with a second valve. The second branch (244) is used to transport the alkaline solution to the alkaline electrolysis unit (100) for circulating electrolysis.

6. An online extraction and enrichment device for heavy water using an alkaline electrolytic cell, comprising an alkaline electrolysis unit (100) and a separation and circulation unit (300), characterized in that: It also includes an online extraction and enrichment unit for heavy water using an alkaline electrolysis cell as described in any one of claims 1-5, wherein the alkaline electrolysis unit (100) generates a gas-liquid mixture and delivers it to a separation and circulation unit (300), and the separation and circulation unit (300) sends the separated alkaline solution to a deuterium-rich water extraction unit (200) for online extraction of deuterium-rich water.

7. The alkaline electrolytic cell online extraction and enrichment device for heavy water according to claim 6, characterized in that: The alkaline electrolysis unit (100) includes an alkaline electrolyzer (110) having an anode side (111) and a cathode side (112); the separation and circulation unit (300) includes an anode gas-liquid separator (310), a cathode gas-liquid separator (320), and a fuel cell (330). The gas-liquid inlet of the anode gas-liquid separator (310) is connected to the anode side (111), and the gas outlet of the anode gas-liquid separator (310) is connected to the positive electrode (332) of the fuel cell (330); the liquid outlet of the anode gas-liquid separator (310) is connected to the anode side (111) of the alkaline electrolyzer (110). The gas-liquid inlet of the cathode gas-liquid separator (320) is connected to the cathode side (112), the gas outlet of the cathode gas-liquid separator (320) is connected to the negative electrode (331) of the fuel cell (330), and the liquid outlet of the cathode gas-liquid separator (320) is connected to the deuterium-rich water extraction unit (200), and the alkaline solution to be treated is delivered to the deuterium-rich water extraction unit (200).

8. The alkaline electrolytic cell online extraction and enrichment device for heavy water according to claim 7, characterized in that: The alkaline electrolysis unit (100) has a refrigeration module, and condenser three (220) and condenser four (260) share the same set of refrigeration modules with the alkaline electrolysis unit (100); or / and, the temperature of condenser three (220) and condenser four (260) is controlled at 10-25°C.

9. An online extraction and enrichment device for heavy water in an alkaline electrolytic cell, characterized in that, The device comprises at least two stages of an alkaline electrolytic cell for online extraction and enrichment of heavy water as described in any one of claims 6-8; wherein the enriched deuterium water after treatment by the previous stage deuterium-rich water extraction unit (200) is connected to the next stage alkaline electrolysis unit (100) for step-by-step electrolysis; and the low-deuterium water after treatment by the next stage separation and circulation unit (300) is connected to the previous stage alkaline electrolysis unit (100) for further electrolysis.

10. The alkaline electrolytic cell online extraction and enrichment equipment for heavy water according to claim 9, characterized in that, The deuterium-rich water stored in the deuterium-rich water storage unit (270) in the previous stage deuterium-rich water extraction unit (200) is connected to the cathode side (112) of the alkaline electrolysis cell (110) in the next stage alkaline electrolysis unit (100); the deuterium-poor water generated after being treated by the fuel cell (330) in the next stage separation and circulation unit (300) is connected to the cathode side (112) of the alkaline electrolysis cell (110) in the previous stage alkaline electrolysis unit (100).

11. An online extraction and enrichment system for heavy water using an alkaline electrolytic cell, characterized in that: It includes a pretreatment module and a deep processing module used in series, and the deep processing module includes a proton exchange membrane electrolyzer; The pretreatment module employs the alkaline electrolytic cell online extraction and enrichment device for heavy water as described in any one of claims 6-8; or the alkaline electrolytic cell online extraction and enrichment device for heavy water as described in any one of claims 9-10.

12. A method for online extraction and enrichment of heavy water in an alkaline electrolytic cell, comprising the alkaline electrolytic cell online extraction and enrichment device as described in any one of claims 6-8, characterized in that, The process is as follows: S1. Water electrolysis is performed using an alkaline electrolysis unit (100); S2. The gas-liquid mixture generated by the alkaline electrolysis unit (100) is processed by the separation circulation unit (300), and the separated alkaline solution is sent to the deuterium-rich water extraction unit (200) for online extraction of deuterium-rich water.

13. The method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to claim 12, characterized in that: During the deuterium-rich water extraction unit (200), the water ring vacuum pump (230) adopts a staged working fluid supply mode, including: Initial vacuum stage: Using the alkaline solution pre-stored in the alkaline solution buffer tank (240) as the working fluid, the alkaline solution is pre-circulated in a closed loop through the alkaline solution circulation loop between the alkaline solution buffer tank (240) and the water ring vacuum pump (230) to establish the required negative pressure environment inside the flash tank (210); Continuous operation phase: The working fluid is switched to continuous alkaline solution from the flash tank (210). The alkaline solution is mixed with non-condensable gas from the deuterium-rich water storage tank (270) by the water ring vacuum pump (230) and then sent to the alkaline buffer tank (240). After gas-liquid separation, the working alkaline solution flows back from the alkaline buffer tank (240) to the cathode side (112) in the alkaline electrolysis unit (100) and no longer flows directly back to the water ring vacuum pump (230).

14. The method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to claim 13, characterized in that: The volume of alkali solution pre-stored in the alkali buffer tank (240) is 1 / 3 to 2 / 3 of the total volume of the alkali buffer tank (240).

15. The method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to claim 13, characterized in that: Automatic control valves are provided on the reflux branch between the alkali buffer tank (240) and the water ring vacuum pump (230), and on the reflux branch between the alkali buffer tank (240) and the alkaline electrolysis unit (100), and are switched in linkage according to the vacuum signal in the flash tank (210).

16. The method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to claim 12, characterized in that, The gas-liquid mixture generated on the anode side (111) of the alkaline electrolysis unit (100) is sent to the anode gas-liquid separator (310) in the separation circulation unit (300) for processing, and the separated alkaline solution is returned to the anode side (111); the gas-liquid mixture generated on the cathode side (112) of the alkaline electrolysis unit (100) is sent to the cathode gas-liquid separator (320) in the separation circulation unit (300) for processing, and the separated alkaline solution is sent to the deuterium-rich water extraction unit (200) for online extraction of deuterium-rich water.

17. The method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to claim 12, characterized in that: When the water ring vacuum pump (230) is in continuous operation, the feed rate of the alkaline solution buffer tank (240) to the alkaline electrolysis unit (100) is 0.8-5200 L / h, and the rate at which the alkaline solution buffer tank (240) discharges non-condensable gas through the buffer tank non-condensable gas discharge port (242) is 0.3-1850 NL / h.

18. A method for online extraction and enrichment of heavy water in an alkaline electrolytic cell according to any one of claims 12-17, characterized in that: The flash temperature range of the flash evaporator (210) is 60~65 ℃; Or / and, the electrolysis temperature of the alkaline electrolytic cell (110) in the alkaline electrolysis unit (100) is 55-90℃; Or / and, the feed rate of the liquid delivered by the separation circulation unit (300) to the flash tank (210) is 1.0-5500 L / h; Or / and, a condenser three (220) is provided between the liquid outlet of the flash tank (210) and the alkali inlet (231) of the water ring vacuum pump (230), and the feed rate of the condenser three (220) to the water ring vacuum pump (230) is 0.8-5200 L / h; Or / and, a condenser four (260) is provided between the outlet of the flash tank (210) and the deuterium-rich water storage tank (270), and the feed rate of the condenser four (260) to the deuterium-rich water storage tank (270) is 0.05-270 kg / h.

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