Low-temperature rectification process system for preparing ultralow-concentration deuterium-depleted water

Abstract

The utility model discloses a low-temperature rectification process system for preparing ultralow-concentration deuterium-depleted water, and relates to the technical field of preparation of deuterium-depleted water. The system comprises a low-temperature rectification system, wherein the low-temperature rectification system is provided with a feeding pipeline, a low-deuterium-hydrogen isotope gas pipeline and a high-deuterium-hydrogen isotope gas pipeline; the feeding pipeline is provided with a feeding mass flow controller; the low-deuterium hydrogen isotope gas pipeline is provided with a first discharge mass flow controller and is connected with a gas conversion system; the deuterium-rich hydrogen isotope gas pipeline is provided with a second discharge mass flow controller and is connected with an exhaust pipeline through a flame arrester; the inlet side of the flame arrester is further connected with a vacuum pump, the inlet side of the vacuum pump is connected with a third pneumatic valve, and the third pneumatic valve is connected with a low-deuterium-hydrogen isotope gas pipeline and connected with the inlet side of the flame arrester through a safety protection discharging system. According to the utility model, the separation efficiency of hydrogen isotopes is improved, so that ultralow-concentration deuterium-depleted water is produced more effectively, and compared with the prior art, the preparation process is simplified conveniently.

Description

Technical Field

[0001] The utility model relates to the technical field of the preparation of low-deuterium water, and particularly relates to a low-temperature rectification process system for preparing ultra-low-concentration low-deuterium water. Background Art

[0002] Protium and deuterium are stable isotopes of hydrogen. Different structures of protium and deuterium atoms lead to certain differences in their physical and chemical properties. The deuterium abundance in natural water and natural hydrogen in nature is about 150 ppm, which varies with factors such as altitude and latitude. Water with a deuterium concentration lower than the deuterium abundance of natural water is called low-deuterium water or ultra-light water, and low-deuterium water with a concentration lower than 5 ppm is called ultra-low-deuterium water. Some studies have shown that low-deuterium water can not only activate human cells and significantly promote enzyme reactions, but also increase the activity value of NK cells and enhance the human immune function. At the same time, low-deuterium water can also inhibit cell carcinogenesis and cancer cell proliferation, thus having the function of cancer prevention and health care.

[0003] The water-hydrogen dual-temperature exchange method and the water rectification method are the mainstream methods for the production of low-deuterium water at present. The water-hydrogen dual-temperature exchange method is based on the characteristics of the non-equiprobable equilibrium distribution of hydrogen and deuterium in the reaction, and the principle that the separation factor of the exchange reaction decreases with the increase of temperature, to separate hydrogen and deuterium. The water rectification method is to separate by rectification using the difference in the saturated vapor pressures of isotope water vapor. However, when these two methods are used to prepare ultra-low-deuterium water, the following problems exist: (1) Since the process includes liquid-phase catalytic exchange and phase transformation processes, and involves the material cycle between high and low-temperature towers, the operation control of the water-hydrogen dual-temperature exchange method for obtaining product water with ultra-low deuterium content is cumbersome and the equipment is very complex; (2) Although the water rectification method has advantages such as high separation efficiency and large output in the preparation of low-deuterium water in the range of 20 ppm to 130 ppm, when preparing ultra-low-deuterium water, the water rectification method needs to adopt methods such as cascading to further increase the separation coefficient, which will increase the complexity of the equipment.

[0004] Therefore, how to improve the hydrogen-deuterium separation efficiency and simplify the ultra-low-deuterium water preparation process has become one of the key research points in this field. Summary of the Utility Model

[0005] The utility model aims to provide a low-temperature rectification process system for preparing ultra-low-concentration low-deuterium water, which can solve the above problems.

[0006] To solve the above problems, the technical solution adopted by the utility model is as follows:

[0007] The utility model provides a low-temperature rectification process system for preparing ultra-low concentration low-deuterium water, which includes a low-temperature rectification system. The low-temperature rectification system is provided with a feed pipeline, a low-deuterium hydrogen isotope gas pipeline and a deuterium-rich hydrogen isotope gas pipeline; a feed mass flow controller is arranged on the feed pipeline; a first discharge mass flow controller is arranged on the low-deuterium hydrogen isotope gas pipeline and is connected to a gas conversion system; a second discharge mass flow controller is arranged on the deuterium-rich hydrogen isotope gas pipeline and is connected to an exhaust pipeline through a flame arrester; the inlet side of the flame arrester is also connected to the outlet side of a vacuum pump, the inlet side of the vacuum pump is connected to one end of a third pneumatic valve, the other end of the third pneumatic valve is connected to the side outlet of the low-deuterium hydrogen isotope gas pipeline above the first discharge mass flow controller, and is connected to the inlet side of the flame arrester through a safety protection discharge system.

[0008] As a further description of the above technical solution: The gas conversion system includes a catalytic reaction bed and a cooling heat exchanger. A dry air mass flow controller is arranged at the dry air inlet of the catalytic reaction bed. The low-deuterium gas inlet of the catalytic reaction bed is connected to the low-deuterium hydrogen isotope gas pipeline, and the outlet of the catalytic reaction bed is connected to the cooling heat exchanger.

[0009] As a further description of the above technical solution: The catalytic reaction bed has a porous structure.

[0010] As a further description of the above technical solution: The safety protection discharge system includes a pressure relief valve, a first pneumatic valve and a second pneumatic valve. The outlet side of the pressure relief valve is connected to the flame arrester through the first pneumatic valve and a pipeline. The inlet side of the pressure relief valve is provided with the second pneumatic valve. The inlet of the second pneumatic valve is connected to the third pneumatic valve, and the side outlet of the low-deuterium hydrogen isotope gas pipeline above the first discharge mass flow controller.

[0011] As a further description of the above technical solution: The low-temperature rectification system includes a vacuum cold box, a rectification column, a rectification column condenser and a rectification column reboiler installed in the vacuum cold box, a refrigerating machine connected to the rectification column condenser in a matching manner, and a molecular pump group with a suction port connected to the vacuum cold box; the rectification column is connected to the feed pipeline, the low-deuterium hydrogen isotope gas pipeline and the deuterium-rich hydrogen isotope gas pipeline. The rectification column condenser and the rectification column reboiler are respectively arranged at the upper and lower ends of the rectification column and respectively act on the low-deuterium hydrogen isotope gas pipeline and the deuterium-rich hydrogen isotope gas pipeline.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] 1) The low-temperature rectification process system of the utility model improves the separation efficiency of hydrogen isotopes through an optimized low-temperature rectification process flow, thereby more effectively producing ultra-low concentration low-deuterium water.

[0014] 2) Compared with the traditional dual-temperature exchange method and water rectification method, the system of the present utility model reduces complex material circulation and high and low-temperature tower equipment, simplifying the entire preparation process.

[0015] 3) By setting a feed mass flow controller and two discharge mass flow controllers, the present utility model realizes precise control of the feed and discharge, ensuring the stability and consistency of product quality.

[0016] 4) Since the complex cascade equipment and material circulation between high and low-temperature towers are avoided, the system of the present utility model significantly reduces energy consumption during the preparation of ultra-low deuterium water.

[0017] 5) By connecting a safety protection discharge system, the present utility model improves the safety of the entire low-temperature rectification process, ensuring timely pressure relief in case of abnormalities and preventing system damage or safety accidents.

[0018] 6) It is convenient to reduce manual intervention, improving the operation convenience and production efficiency.

[0019] 7) Since the energy consumption is reduced and the process flow is simplified, the system of the present utility model reduces the impact on the environment while producing ultra-low deuterium water, meeting the requirements of green chemistry and sustainable development.

[0020] 8) This process system is more likely to produce ultra-low deuterium water with higher purity, meeting the strict requirements for water quality in specific application fields.

[0021] To make the above objects, features, and advantages of the present utility model more obvious and understandable, specific embodiments of the present utility model are hereinafter given, and in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present utility model, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 is the low-temperature rectification process flow chart for preparing ultra-low deuterium water in the embodiment;

[0024] Figure 2 is the analysis result of the deuterium content of the low-temperature rectification test product water for preparing ultra-low deuterium water in the embodiment;

[0025] In the figure: 1 - Feed mass flow controller, 2 - First discharge mass flow controller, 3 - Second discharge mass flow controller, 4 - Dry air mass flow controller, 5 - Vacuum cold box, 6 - Rectification column condenser, 7 - Rectification column reboiler, 8 - Rectification column, 9 - Molecular pump group, 10 - Refrigerator, 11 - Vacuum pump, 12 - Pressure relief valve, 13 - Flame arrester, 14 - Catalytic reaction bed, 15 - Cooling heat exchanger, 16 - Control system, 17 - Feed pipeline, 18 - Low-deuterium hydrogen isotope gas pipeline, 19 - High-deuterium hydrogen isotope gas pipeline, 20 - First pneumatic valve, 21 - Second pneumatic valve, 22 - Third pneumatic valve. Detailed implementation mode

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model.

[0027] Please refer to Figure 1 , this embodiment provides a low-temperature rectification process system for preparing ultra-low concentration low-deuterium water, including a control system 16 and a low-temperature rectification system. The low-temperature rectification system is provided with a feed pipeline 17, a low-deuterium hydrogen isotope gas pipeline 18 and a high-deuterium hydrogen isotope gas pipeline 19; the feed pipeline 17 is provided with a feed mass flow controller 1; the low-deuterium hydrogen isotope gas pipeline 18 is provided with a first discharge mass flow controller 2 and is connected to a gas conversion system; the high-deuterium hydrogen isotope gas pipeline 19 is provided with a second discharge mass flow controller 3 and is connected to an exhaust pipeline through a flame arrester 13; the inlet side of the flame arrester 13 is also connected to the outlet side of a vacuum pump 11, the inlet side of the vacuum pump 11 is connected to one end of a third pneumatic valve 22, and the other end of the third pneumatic valve 22 is connected to the side outlet of the low-deuterium hydrogen isotope gas pipeline 18 above the first discharge mass flow controller 2, and is connected to the inlet side of the flame arrester 13 through a safety protection discharge system.

[0028] Among them, the feed mass flow controller 1 is used to control the flow rate of the raw material gas entering the feed pipeline 17, that is, to control the flow rate of the raw material gas entering the low-temperature rectification system. The first discharge mass flow controller 2 is used to control the extraction flow rate of the low-deuterium hydrogen isotope gas in the low-temperature rectification system. The second discharge mass flow controller 3 is used to control the extraction flow rate of the high-deuterium hydrogen isotope gas in the low-temperature rectification system.

[0029] The gas conversion system is used to react low-deuterium hydrogen isotope gas with ultra-low deuterium content and dry air to oxidize into water, thus completing the preparation of ultra-low deuterium water. It includes a catalytic reaction bed 14 and a cooling heat exchanger 15. A dry air mass flow controller 4 is provided at the dry air inlet of the catalytic reaction bed 14. The low-deuterium gas inlet of the catalytic reaction bed 14 is connected to the low-deuterium hydrogen isotope gas pipeline 18. The discharge port of the catalytic reaction bed 14 is connected to the cooling heat exchanger 15.

[0030] Among them, the catalytic reaction bed 14 is used to provide a place for the hydrogen-oxygen reaction. The cooling heat exchanger 15 is used to condense and collect the product water generated after the hydrogen-oxygen reaction. The dry air mass flow controller 4 is used to control the supply flow of dry air in the gas conversion system, and a vacuum pump 11 is configured for pipeline evacuation.

[0031] The catalytic reaction bed 14 has a porous structure, that is, a structure with a large number of pores inside the material. These pores can be randomly distributed or arranged orderly. The pore size and shape of the porous structure can be diversified. The pores can be straight or tortuous. This structure is widely applied in the catalytic process because it provides a large specific surface area and good fluid permeability.

[0032] The safety protection and discharge system is used to provide safety protection for the process of generating ultra-low deuterium water. It includes a pressure relief valve 12, a first pneumatic valve 20 and a second pneumatic valve 21. The outlet side of the pressure relief valve 12 is connected to a flame arrester 13 through the first pneumatic valve 20 and a pipeline. A second pneumatic valve 21 is provided on the inlet side of the pressure relief valve 12. The inlet of the second pneumatic valve 21 is connected to a third pneumatic valve 22, and the side outlet of the low-deuterium hydrogen isotope gas pipeline 18 above the first discharge mass flow controller 2. During the operation of the safety protection and discharge system, the first pneumatic valve 20 and the second pneumatic valve 21 are in the open state. Once an abnormal condition occurs in the system and there is a risk of leakage and explosion during overpressure operation of the system, the hydrogen in the system will be relieved through the pressure relief valve 12 and discharged to the exhaust pipeline through the flame arrester 13. The flame arrester 13 can prevent the backfire of the exhaust pipeline to ensure the safety of the hydrogen in the system.

[0033] Among them, the pressure relief valve 12 is used for pressure relief and discharge during the accident of temperature loss and overpressure in the low-temperature rectification process. The flame arrester 13 is used to prevent the backflow of the flame in case of accidental fire during the discharge of hydrogen isotope gas.

[0034] The low-temperature rectification system is used for the separation of hydrogen isotope gases to obtain low-deuterium gas and deuterium-rich gas with ultra-low content, including a vacuum cold box 5, a rectification column 8, a rectification column condenser 6, and a rectification column reboiler 7 installed in the vacuum cold box 5, a refrigerator 10 connected to the rectification column condenser 6 in a matching manner, and a molecular pump set 9 with a suction port connected to the vacuum cold box 5; the rectification column 8 is connected to a feed pipeline 17, a low-deuterium hydrogen isotope gas pipeline 18, and a deuterium-rich hydrogen isotope gas pipeline 19, and the rectification column condenser 6 and the rectification column reboiler 7 are respectively arranged at the upper and lower ends of the rectification column 8 and respectively act on the low-deuterium hydrogen isotope gas pipeline 18 and the deuterium-rich hydrogen isotope gas pipeline 19.

[0035] Among them, the vacuum cold box 5 is used to provide an adiabatic environment for the low-temperature rectification process, the refrigerator 10 is used to provide the cooling capacity required for the low-temperature rectification process, the rectification column condenser 6 is used to condense the hydrogen isotope gas during the rectification process and obtain low-deuterium hydrogen isotope gas, the rectification column reboiler 7 is used to evaporate the hydrogen isotope gas during the rectification process and obtain deuterium-rich hydrogen isotope gas, the rectification column 8 is used to provide a place for the mass transfer process of hydrogen isotopes, and the molecular pump set 9 is used for evacuating the vacuum cold box 5.

[0036] The control system 16 is connected to the low-temperature rectification system, the gas conversion system, the safety protection and emission system, each flow controller, and the valve island of each pneumatic valve, facilitating the realization of the function of monitoring the process parameters of the system. Specifically, the control system 16 can adjust the flow settings within the system and control the start and stop of the valves; the control system 16 monitors the pressure, temperature, liquid level of the rectification column in the low-temperature rectification system and the vacuum degree of the vacuum cold box 5, and controls the heating power of the reboiler and the temperature of the condenser; the control system 16 monitors the temperature of the catalytic reaction bed 14 and the temperature of the cooling heat exchanger 15 in the gas conversion system.

[0037] The low-temperature rectification system of the system described in this embodiment is the core component of the process. It mainly utilizes the difference in vapor pressures between the components in the hydrogen isotope mixture, through multiple partial vaporizations and partial condensations, to achieve the depletion and enrichment of the light and heavy components in the gas-liquid phases, ultimately achieving the goal of separating the liquid mixture and obtaining an ultra-low-deuterium product gas, and finally preparing ultra-low-deuterium water through catalytic oxidation.

[0038] Using the system described in this embodiment to prepare ultra-low-concentration low-deuterium water, the process includes:

[0039] (1) Conduct a leak rate test on the overall system until it meets the safety requirements for hydrogen operation.

[0040] (2) Determine the working vacuum degree, start the molecular pump set 9 to evacuate the vacuum cold box 5 until the vacuum degree of the vacuum cold box 5 reaches the working vacuum degree.

[0041] (3) Flush and evacuate the system with high-purity nitrogen, and repeat the operation at least 3 times. Each process is as follows: the upper and lower product extraction valves of the distillation column 8 (the upper product extraction valve is the first product discharge mass flow controller 2, and the lower product extraction valve is the second product discharge mass flow controller 3. When closed, their flow control is 0) are closed. Through the feed pipeline 17, nitrogen is filled into the distillation column 8 until 1.3 bar, and then the inlet valve (i.e., the feed mass flow controller 1, and its flow control adjustment is 0 when closed) is closed. The vacuum pump 11 and the third pneumatic valve 22 are opened to evacuate the gas in the system pipeline (the evacuation path is: distillation column 8 → low-deuterium hydrogen isotope gas pipeline 18 → third pneumatic valve 22 → vacuum pump 11 → flame arrester 13 → exhaust pipeline), and one nitrogen flush is completed.

[0042] (4) Flush and evacuate the system with the raw material gas (natural hydrogen with a deuterium abundance of about 150 ppm), and repeat the operation at least 3 times. Each process is as follows: the upper and lower product extraction valves of the distillation column 8 (the upper product extraction valve is the first product discharge mass flow controller 2, and the lower product extraction valve is the second product discharge mass flow controller 3. When closed, their flow control is 0) are closed. Through the feed pipeline 17, the raw material gas is filled into the distillation column 8 until 1.3 bar, and then the inlet valve (i.e., the feed mass flow controller 1, and its flow control adjustment is 0 when closed) is closed. The vacuum pump 11 and the third pneumatic valve 22 are opened to evacuate the gas in the system pipeline (the evacuation path is: distillation column 8 → low-deuterium hydrogen isotope gas pipeline 18 → third pneumatic valve 22 → vacuum pump 11 → flame arrester 13 → exhaust pipeline), and one raw material gas flush is completed.

[0043] (5) Control the inlet flow rate of the raw material gas, fill the raw material gas into the distillation column 8, close the upper and lower product extraction valves of the distillation column 8, and at the same time start the refrigerator 10, and use the distillation column condenser 6 to cool the distillation column 8 until liquid hydrogen is generated in the distillation column reboiler 7.

[0044] (6) After the distillation column 8 is successfully cooled, close the feed of the distillation column 8, set the temperature of the distillation column condenser 6 and the heating power of the distillation column reboiler 7, and perform total reflux.

[0045] (7) After total reflux is completed, set the feed flow rate of the distillation column 8, the extraction flow rate of the upper product (low-deuterium hydrogen isotope gas), the extraction flow rate of the lower product (deuterium-rich hydrogen isotope gas), and the dry air flow rate, and open the cooling heat exchanger 15, and the stable distillation stage begins.

[0046] (8) The gas conversion system continuously collects the ultra-low-deuterium water product, detects the ultra-low-deuterium water product until the deuterium content of the product water sample meets the requirements, and the system continuously generates ultra-low-deuterium water.

[0047] When the system is shut down, first, the feed gas inlet flow is closed by using the feed mass flow controller 1, the upper product (low-deuterium hydrogen isotope gas) extraction flow is closed by using the first product discharge mass flow controller 2, the refrigerator 10 and the molecular pump set 9 are turned off, and the vacuum pump 11 is turned on to continuously evacuate the rectification column 8. When the system temperature returns to normal temperature, all valves and components are closed.

[0048] Through tests, the ultra-low deuterium water is prepared by using the above system, and the deuterium content of the produced low-deuterium water all reaches below the detection limit (5 ppm) of the analytical instrument, as shown in the appendix Figure 2 shown. The appendix Figure 2 is the analysis result of the deuterium content of the product water in the low-temperature rectification test for preparing ultra-low deuterium water. Among them, the ordinate Molar fraction is the molar fraction of deuterium element in water, and the unit is parts per million ppm. The abscissa Time is time, and the unit is hour. The appendix Figure 2 is the deuterium content result of the low-deuterium water generated through the above low-deuterium water generation process. The result analysis is carried out by using an isotope mass spectrometer, and all the analysis results reach below the detection limit (5 ppm) of the analytical instrument.

[0049] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A low-temperature rectification process system for preparing ultra-low concentration low-deuterium water, characterized in that, It includes a cryogenic distillation system, and the cryogenic distillation system is provided with a feed pipeline (17), a low-deuterium hydrogen isotope gas pipeline (18) and a deuterium-rich hydrogen isotope gas pipeline (19); a feed mass flow controller (1) is provided on the feed pipeline (17); a first discharge mass flow controller (2) is provided on the low-deuterium hydrogen isotope gas pipeline (18), and it is connected to a gas conversion system; a second discharge mass flow controller (3) is provided on the deuterium-rich hydrogen isotope gas pipeline (19), and it is connected to an exhaust pipeline through a flame arrester (13); the inlet side of the flame arrester (13) is also connected to the outlet side of a vacuum pump (11), the inlet side of the vacuum pump (11) is connected to one end of a third pneumatic valve (22), the other end of the third pneumatic valve (22) is connected to the side outlet of the low-deuterium hydrogen isotope gas pipeline (18) above the first discharge mass flow controller (2), and it is connected to the inlet side of the flame arrester (13) through a safety protection discharge system.

2. The low-temperature rectification process system for preparing ultra-low concentration low-deuterium water according to claim 1, characterized in that, The gas conversion system includes a catalytic reaction bed (14) and a cooling heat exchanger (15). A dry air mass flow controller (4) is provided at the dry air inlet of the catalytic reaction bed (14), the low-deuterium gas inlet of the catalytic reaction bed (14) is connected to the low-deuterium hydrogen isotope gas pipeline (18), and the discharge port of the catalytic reaction bed (14) is connected to the cooling heat exchanger (15).

3. The low-temperature rectification process system for preparing ultra-low concentration low-deuterium water according to claim 2, characterized in that, The catalytic reaction bed (14) is of a porous structure.

4. The cryogenic distillation process system for preparing ultra-low concentration low-deuterium water according to claim 1, wherein The safety protection discharge system includes a pressure relief valve (12), a first pneumatic valve (20) and a second pneumatic valve (21). The outlet side of the pressure relief valve (12) is connected to the flame arrester (13) through the first pneumatic valve (20) and a pipeline. The inlet side of the pressure relief valve (12) is provided with the second pneumatic valve (21). The inlet of the second pneumatic valve (21) is connected to the third pneumatic valve (22), and the side outlet of the low-deuterium hydrogen isotope gas pipeline (18) above the first discharge mass flow controller (2).

5. The low-temperature rectification process system for preparing ultra-low concentration low-deuterium water according to claim 1, characterized in that, The cryogenic distillation system includes a vacuum cold box (5), a distillation column (8), a distillation column condenser (6) and a distillation column reboiler (7) installed in the vacuum cold box (5), a refrigerating machine (10) connected to the distillation column condenser (6) in a matching manner, and a molecular pump set (9) with an inlet connected to the vacuum cold box (5); the distillation column (8) is connected to the feed pipeline (17), the low-deuterium hydrogen isotope gas pipeline (18) and the deuterium-rich hydrogen isotope gas pipeline (19). The distillation column condenser (6) and the distillation column reboiler (7) are respectively arranged at the upper and lower ends of the distillation column (8), and respectively act on the low-deuterium hydrogen isotope gas pipeline (18) and the deuterium-rich hydrogen isotope gas pipeline (19).

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