Device system and method for separating boron 10 and boron 11 isotopes

Abstract

The invention relates to a separation device system and method for boron 10 and boron 11 isotopes. The separation device system comprises a boron trifluoride purification unit, a boron 10 isotope negative-pressure low-temperature rectification unit and a boron 10 isotope filling unit which are sequentially connected in the material flow direction. The boron 10 isotope negative-pressure low-temperature rectification unit is connected with an air separation nitrogen supply unit; the boron 10 isotope negative-pressure low-temperature rectification unit comprises a structured packing tower and a random packing tower which are connected in series, the bottom of the structured packing tower is connected with an ultra-pure boron trifluoride filling unit, and the bottom of the random packing tower is connected with a boron 11 isotope filling unit; and the separation device system is provided with a vacuumizing system and a PLC (Programmable Logic Controller) control system. The separation device system is used for separating and extracting boron 10 and boron 11 isotopes, and has the advantages of high isotope separation efficiency and yield, low energy consumption and low equipment investment cost.

Description

Technical Field

[0001] The present invention relates to the technical field of isotope separation, and in particular to a device system and method for separating boron 10 and boron 11 isotopes. Background Art

[0002] There are two stable isotopes of natural boron, namely boron 10 ( 10 B) and boron 11( 11 B), the natural abundance of boron 10 is about 19.61%, which has a very strong neutron absorption ability; the natural abundance of boron 11 is about 80.39%. Boron isotopes have very important applications in the fields of nuclear industry, cancer prognosis and treatment, nuclear magnetic tomography, super alloy steel, ultra-high pressure vessels, etc., but the boron isotope separation and extraction technology has not yet been applied in industrial-scale production in China.

[0003] The main methods for separation and extraction of boron isotopes include chemical exchange distillation, cryogenic distillation, adsorption separation, laser separation, etc. At present, chemical exchange distillation and cryogenic distillation are relatively mature methods with industrial application potential in boron isotope separation. Chemical exchange distillation mainly uses the difference in chemical properties of the two isotopes of boron in different compounds to achieve separation through chemical reactions and distillation processes. For example, CN109942005A discloses an industrial production method of boron-10 isotope, wherein methyl ether is pressurized to become liquid, methyl ether liquid is adsorbed by molecular sieve, boron trifluoride gas is distilled by low temperature distillation tower and then comes out from the top of the tower, methyl ether and boron trifluoride undergo complexation reaction in complexation reactor; the generated complex enters exchange reaction distillation tower; the complex is heated by reboiler, and its steam is completely condensed into liquid to re-form boron trifluoride-methyl ether complex, and the refluxed liquid is in convection contact with steam to undergo chemical exchange reaction, so that boron trifluoride-10 gradually enters liquid phase from gas phase, and as the liquid flowing downward enters the tower kettle, the boron trifluoride-11 complex also continuously undergoes exchange reaction from liquid phase to gas phase and rises to the top of the tower. However, this method has the problems of complex process, multi-step reaction and distillation operation, high energy consumption and relatively high production cost.

[0004] Cryogenic distillation is based on the difference in volatility of boron isotopes at low temperatures, and separation is achieved through a cryogenic distillation process. This method usually needs to be operated at extremely low temperatures to take advantage of the slight differences in physical properties of boron isotopes in liquid or solid states. For example, CN119281113A discloses a method and apparatus for separating boron isotopes by cryogenic distillation. 3 The raw material is passed into the first stage tower for the first low temperature distillation to obtain the first tower top material and the first tower bottom material; the first tower top material is passed into the second stage tower for the second low temperature distillation to obtain the second tower top material and the second tower bottom material, and the second tower bottom material and the BF 3The raw materials are recycled after mixing; the first-stage tower and the second-stage tower use ethylene as the circulating medium to provide cooling and heating. This method has good separation effect and can obtain high-purity boron isotopes, but it also requires complex cryogenic equipment and technologies, with relatively harsh operating conditions, high equipment investment and operating costs. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a separation device system and method for boron-10 and boron-11 isotopes. Using the separation device system for the separation and extraction of boron-10 and boron-11 isotopes has the advantages of high isotope separation efficiency and output rate, low energy consumption, and low equipment investment cost.

[0006] To achieve the purpose of this invention, the following technical solutions are adopted:

[0007] In the first aspect, the present invention provides a separation device system for boron-10 and boron-11 isotopes. The separation device system includes a boron trifluoride purification unit, a boron-10 isotope negative-pressure cryogenic distillation unit, and a boron-10 isotope filling unit connected in sequence along the material flow direction; the boron-10 isotope negative-pressure cryogenic distillation unit is connected to an air separation nitrogen supply unit.

[0008] The boron-10 isotope negative-pressure cryogenic distillation unit includes a structured packing tower and a random packing tower arranged in series. The bottom of the structured packing tower is connected to an ultra-high-purity boron trifluoride filling unit, and the bottom of the random packing tower is connected to a boron-11 isotope filling unit; the separation device system is provided with a vacuum pumping system and a PLC control system.

[0009] The separation device system for boron-10 and boron-11 isotopes provided by the present invention removes high-boiling-point impurities and low-boiling-point impurities in industrial boron trifluoride gas through the boron trifluoride purification unit. The production of boron-10 and boron-11 isotope products adopts a series cascade tower form. The front cascade is a series connection of structured packing towers, which can process a large amount of boron trifluoride raw material gas and provide a stable and reliable primary boron-10 raw material gas for subsequent enrichment and concentration; the rear cascade is a series connection of random packing towers. Utilizing the ultra-high separation efficiency of random packing, boron-10 and boron-11 isotopes are quickly concentrated at the top and bottom of the tower. The final products include boron-11 isotope with an atomic abundance of 99.5% and boron-10 isotope of more than 85%. The present invention uses cold nitrogen gas obtained by vaporizing liquid nitrogen from air separation or directly cold nitrogen gas from air separation as the system cold source, while effectively utilizing the cold energy of the air separation system, significantly reducing the energy consumption level of the device system of the present invention, and at the same time removing dynamic equipment such as expanders, saving equipment investment.

[0010] Preferably, the boron trifluoride purification unit includes a boron trifluoride cold trap, a boron trifluoride adsorption membrane, a boron trifluoride mass flow controller, and a boron trifluoride pressure gauge arranged in sequence along the material flow direction.

[0011] The boron trifluoride cold trap is realized through an open liquid nitrogen Dewar flask, and the content of high-boiling impurities in the industrial boron trifluoride gas is controlled below 500 ppm through an atmospheric-pressure liquid nitrogen bath. The inner liner of the open liquid nitrogen Dewar flask is provided with a slag discharge port for discharging high-boiling solidified impurities; the purification of the industrial boron trifluoride low-boiling impurity gas is realized through a boron trifluoride adsorption membrane. The industrial boron trifluoride gas coming out of the boron trifluoride cold trap adsorbs the low-boiling impurity gas through the boron trifluoride adsorption membrane, so that the content of low-boiling impurities in the boron trifluoride gas is lower than 6 ppm; the boron trifluoride mass flow controller is mainly used to count the usage amount of the boron trifluoride raw material gas, so as to provide a reference for further improving the extraction rate of boron-10.

[0012] Preferably, heat-insulating cotton is arranged inside the boron trifluoride cold trap.

[0013] Preferably, a boron trifluoride stop valve is arranged on the pipeline before the boron trifluoride cold trap, and a slag discharge stop valve is connected to the boron trifluoride cold trap.

[0014] Preferably, the number of stages of the structured packing column ≥ 2, and the number of stages of the random packing column ≥ 6.

[0015] The number of stages of the structured packing column ≥ 2, for example, it can be 2, 3, 4, 5 or 6, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0016] The number of stages of the random packing column ≥ 6, for example, it can be 6, 7, 8, 9 or 10, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] The average separation factor between boron-10 and boron-11 is usually about 1.006, so the separation between them requires a huge number of theoretical plates. The structured packing column and the random packing column adopt a multi-stage series form to meet the requirement of the number of theoretical plates in the rectification process. The boron-10 isotope negative-pressure low-temperature rectification unit adopts negative-pressure operation, which can effectively improve the separation factor between boron-10 and boron-10.

[0018] Preferably, structured packing is arranged in the structured packing column, and random Heli-pak packing is arranged in the random packing column.

[0019] The present invention adopts a cascaded tower arrangement in which an efficient structured packing tower and a dumped packing tower are connected in series, which is applicable to the production of boron-10 isotope at an industrial scale. In order to increase the processing capacity of the feed gas in the packing tower, a structured packing tower is used in the primary rectification process, which has the advantages of small tower pressure drop and large feed gas throughput. The structured rectification tower can provide a large amount of semi-finished products for the subsequent enrichment of boron-10 isotope. The processing capacity of the feed gas of the dumped packing is relatively small compared with that of the structured packing, but the equivalent number of theoretical plates of the dumped packing is much higher than that of the structured packing. The structured packing tower is mainly used to separate boron-11 isotope in large quantities to obtain the raw material of crude boron-10 isotope; the dumped packing tower utilizes the ultra-high separation efficiency of the dumped Heli-pak packing to rapidly enrich boron-10 isotope in the top gas phase, and at the same time obtain a high-abundance boron-11 isotope liquid in the bottom liquid phase.

[0020] Preferably, electric heaters are independently arranged at the bottoms of the structured packing tower and the dumped packing tower respectively, and condensers are independently arranged at the tops respectively.

[0021] Preferably, a top pressure gauge is independently arranged at the top of each stage of the structured packing tower and the dumped packing tower respectively.

[0022] Preferably, an exhaust control valve is arranged at the top of each stage of the structured packing tower.

[0023] Preferably, a boron trifluoride purification tower is connected before the first stage of the dumped packing tower in the dumped packing tower, and a boron-10 isotope liquefaction collector is connected after the last stage of the dumped packing tower.

[0024] The boron trifluoride purification tower further reduces the impurity content in the high-purity boron trifluoride gas. The boron trifluoride purification tower is heated by an electric heater, and the cold source at the top comes from the cold nitrogen of the air separation.

[0025] Preferably, the air separation nitrogen supply unit includes an air-bath vaporizer, a cold-source nitrogen control valve and a cold-source nitrogen pressure gauge connected in sequence along the material flow direction.

[0026] The air separation nitrogen supply unit provides cooling capacity for the boron-10 isotope negative-pressure low-temperature rectification unit. The liquid nitrogen separated from the air separation is vaporized and reheated to cold nitrogen by the air-bath vaporizer and used as the cold source of the boron-10 isotope negative-pressure low-temperature rectification unit. The input cooling capacity of the system is adjusted by the cold-source nitrogen control valve. While making full use of the cold energy of the air separation, the operation energy consumption of the present invention is greatly reduced, dynamic equipment such as expanders is removed, and the investment cost is reduced.

[0027] Preferably, the inlet of the air-bath vaporizer is connected with an air separation liquid nitrogen pipeline and an air separation nitrogen pipeline. An air separation liquid nitrogen stop valve is arranged on the air separation liquid nitrogen pipeline, and an air separation nitrogen stop valve is arranged on the air separation nitrogen pipeline.

[0028] Preferably, the boron-10 isotope filling unit includes a boron-10 isotope liquefaction collector, a first double-temperature flexible coiled tube, a boron-10 filling mass flow controller, and a boron-10 filling electronic balance, which are connected in sequence along the material flow direction; a heater is provided at the bottom of the boron-10 isotope liquefaction collector, and the heater is used for vaporizing and pressurizing the boron-10 isotope liquid.

[0029] The boron-10 isotope product gas is first liquefied, and then vaporized and pressurized by heating nitrogen. The pressurized boron-10 isotope gas is reheated in the air through the first double-temperature flexible coiled tube. Due to the scarcity of boron-10 isotope, its filling flow rate is controlled by a mass flow controller, and finally the filling amount of the steel cylinder is accurately measured by the boron-10 filling electronic balance.

[0030] The boron-10 filling electronic balance is a milligram-level electronic balance.

[0031] Preferably, the boron-11 isotope filling unit includes a boron-11 isotope liquid collector, a second double-temperature flexible coiled tube, a boron-11 filling mass flow controller, and a boron-11 filling electronic balance, which are connected in sequence along the material flow direction; the inlet of the boron-11 isotope liquid collector is connected with a boron-11 isotope liquid pipeline and a first heating nitrogen pipeline, and the heating nitrogen introduced into the first heating nitrogen pipeline serves as the heat source for vaporizing and pressurizing.

[0032] The boron-11 isotope is mainly collected at the bottom of the last-stage random packing tower. The boron-11 isotope product is first stored in the boron-11 isotope liquid collector. When filling is required, heating nitrogen is introduced into the boron-11 isotope as the heat source for vaporizing and pressurizing the boron-11 isotope, and the boron-11 isotope is reheated to room temperature through the second double-temperature flexible coiled tube. The boron-11 filling mass flow controller is used to control the filling speed of the boron-11 isotope gas, and the filling mass of the steel cylinder is determined by the boron-11 filling electronic balance.

[0033] The boron-11 filling electronic balance is a gram-level electronic balance.

[0034] Preferably, a boron-11 isotope liquid stop valve is provided on the boron-11 isotope liquid pipeline, and a first heating nitrogen stop valve is provided on the first heating nitrogen pipeline.

[0035] Preferably, the boron-11 isotope liquid collector is provided with a first vaporization pressure gauge and a boron-11 isotope gas breather valve.

[0036] Preferably, the ultra-high purity boron trifluoride filling unit includes a boron trifluoride liquefaction collector and a third double-temperature flexible coiled tube, which are connected in sequence along the material flow direction; the inlet of the boron trifluoride liquefaction collector is connected with an ultra-high purity boron trifluoride liquid pipeline and a second heating nitrogen pipeline, and the heating nitrogen introduced into the second heating nitrogen pipeline serves as the heat source for vaporizing and pressurizing.

[0037] The exhaust gas discharged from the boron-10 isotope negative-pressure low-temperature rectification unit is ultra-high purity boron trifluoride gas, which can be regularly collected into a boron trifluoride liquefaction collector. When vaporization and filling into cylinders are required, it can be vaporized and pressurized by heating nitrogen, then reheated to room temperature through the third reheating flexible coiled tube, and then directly filled into cylinders by the partial pressure method.

[0038] Preferably, an ultra-high purity boron trifluoride liquid stop valve is provided on the ultra-high purity boron trifluoride liquid pipeline, and a second heating nitrogen stop valve is provided on the second heating nitrogen pipeline.

[0039] Preferably, the boron trifluoride liquefaction collector is provided with a second vaporization pressure gauge and an ultra-high purity boron trifluoride gas breather valve.

[0040] Preferably, the vacuum pumping system includes a system vacuum pumping panel, which is sequentially connected with a vacuum resistance gauge, a vacuum pumping diaphragm valve, a rotary vane vacuum pump, a muffler and a check valve.

[0041] The multiple vacuum pumping ports of the separation device system are uniformly arranged on the system vacuum pumping panel, and the pipeline is simple and clear; the rotary vane vacuum pump is a mechanical rotary vane vacuum pump with an ultimate vacuum degree of 0.2 Pa; the adopted vacuum resistance gauge has an ultimate sensitivity of 0.02 Pa and is used to measure the vacuum degree of the rotary vane vacuum pump pumping port; the output signal of the vacuum resistance gauge is used to control the action of the vacuum pumping diaphragm valve.

[0042] In the present invention, the PLC control system controls the conveying amount of the purified boron trifluoride raw material gas, and accumulates the actual usage amount of the boron trifluoride raw material gas through the boron trifluoride mass flow controller; the PLC control system controls the power of the electric heater of the boron-10 isotope negative-pressure low-temperature rectification unit, so as to control the actual evaporation amount in the structured packing tower and the dumped packing tower; the PLC control system controls the cold source nitrogen flow rate, adjusts the cold quantity input of the system, and controls the boron trifluoride condensation amount in the condenser; the PLC control system controls the boron-10 filling mass flow controller, so as to adjust the flow rate of the boron-10 isotope product gas and accumulate the actual filling amount of the product; the PLC control system controls the boron-11 filling mass flow controller, so as to adjust the flow rate of the boron-11 isotope product gas and accumulate the actual filling amount of the product; the PLC control system controls the exhaust regulating valves of the first-stage and last-stage structured packing towers to adjust the boron-10 isotope gas outlet amount at the top of the tower; the trigger signal of the vacuum resistance gauge is fed back to the PLC control system, and the control system controls the opening and closing of the vacuum pumping diaphragm valve.

[0043] In a second aspect, the present invention provides a method for separating boron-10 and boron-11 isotopes. The separation method is carried out through the boron-10 and boron-11 isotope separation device system described in the first aspect, and the separation method includes the following steps:

[0044] Industrial boron trifluoride gas is successively subjected to purification treatment and negative-pressure low-temperature rectification treatment to obtain boron-10 isotope product gas, boron-11 isotope liquid, and ultra-high-purity boron trifluoride liquid.

[0045] The obtained boron-10 isotope product gas is liquefied and accumulated, and then subjected to the first vaporization and pressurization treatment. The obtained gas is reheated to room temperature and then metered and filled. The obtained boron-11 isotope liquid is introduced into heated nitrogen for the second vaporization and pressurization treatment. The obtained gas is reheated to room temperature and then metered and filled. The obtained ultra-high-purity boron trifluoride liquid is introduced into heated nitrogen for the third vaporization and pressurization treatment. The obtained gas is reheated to room temperature and then subjected to partial pressure filling.

[0046] The separation method of boron-10 and boron-11 isotopes provided by the present invention uses purified industrial boron trifluoride gas as the raw material, and enriches boron-10 and boron-11 isotope products through negative-pressure low-temperature rectification treatment, which is suitable for industrial-scale production.

[0047] Preferably, the purification treatment includes impurity removal by atmospheric-pressure liquid nitrogen bath, membrane adsorption impurity removal, and deep purification carried out in sequence.

[0048] Preferably, the end point of the impurity removal by atmospheric-pressure liquid nitrogen bath is to make the content of high-boiling-point impurities ≤ 500 ppm. For example, it can be 500 ppm, 400 ppm, 300 ppm, 200 ppm, or 100 ppm, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0049] The high-boiling-point impurities in the present invention refer to those with a boiling point ≥ -80°C. The high-boiling-point impurities mainly include moisture, carbon dioxide, hydrogen sulfide, etc.

[0050] Preferably, the temperature of the membrane adsorption impurity removal is -80°C to -65°C. For example, it can be -80°C, -75°C, -72°C, -70°C, or -65°C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0051] Preferably, the end point of the membrane adsorption impurity removal is to make the content of low-boiling-point impurities ≤ 6 ppm. For example, it can be 6 ppm, 5 ppm, 4 ppm, 2 ppm, or 1 ppm, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0052] The low-boiling-point impurities in the present invention refer to those with a boiling point ≤ -120°C. The low-boiling-point impurities mainly include carbon monoxide, hydrogen, nitrogen, etc.

[0053] Preferably, the temperature of the deep purification is -190°C to -180°C. For example, it can be -190°C, -188°C, -185°C, -182°C, or -180°C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0054] Preferably, the pressure of the vacuum low-temperature rectification treatment is ≤ 70 KPaA. For example, it can be 70 KPaA, 68 KPaA, 65 KPaA, 60 KPaA, or 55 KPaA, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0055] Preferably, the temperature of the vacuum low-temperature rectification treatment is from -106.8 °C to -104.8 °C. For example, it can be -106.8 °C, -106.2 °C, -105.8 °C, -105.2 °C, or -104.8 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0056] Preferably, the temperature of the first vaporization and pressurization treatment is from -60 °C to -45 °C, and the pressure is 220 - 260 KPa.

[0057] The temperature of the first vaporization and pressurization treatment is from -60 °C to -45 °C. For example, it can be -60 °C, -55 °C, -50 °C, or -45 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0058] The pressure of the first vaporization and pressurization treatment is 220 - 260 KPa. For example, it can be 220 KPa, 230 KPa, 240 KPa, 250 KPa, or 260 KPa, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0059] Preferably, the temperature of the second vaporization and pressurization treatment is from -60 °C to -45 °C, and the pressure is 220 - 260 KPa.

[0060] The temperature of the second vaporization and pressurization treatment is from -60 °C to -45 °C. For example, it can be -60 °C, -55 °C, -50 °C, or -45 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0061] The pressure of the second vaporization and pressurization treatment is 220 - 260 KPa. For example, it can be 220 KPa, 230 KPa, 240 KPa, 250 KPa, or 260 KPa, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0062] Preferably, the temperature of the third vaporization and pressurization treatment is from -60 °C to -45 °C, and the pressure is 220 - 260 KPa.

[0063] The temperature of the third vaporization and pressurization treatment is -60°C to -45°C. For example, it can be -60°C, -55°C, -50°C or -45°C, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0064] The pressure of the third vaporization and pressurization treatment is 220 - 260 KPa. For example, it can be 220 KPa, 230 KPa, 240 KPa, 250 KPa or 260 KPa, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0065] The reheating to normal temperature means reheating to a temperature of 15 - 30°C. For example, it can be 15°C, 20°C, 25°C or 30°C, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] The separation device system of boron - 10 and boron - 11 isotopes provided by the present invention removes high - boiling - point impurities and low - boiling - point impurities in industrial boron trifluoride gas through a boron trifluoride purification unit. The production of boron - 10 and boron - 11 isotope products adopts a series - cascade tower form. The front - end cascade is a series connection of structured packing towers, which can process a large amount of boron trifluoride raw material gas and provide a stable and reliable primary boron - 10 raw material gas for subsequent enrichment and concentration. The rear - end cascade is a series connection of random packing towers. Utilizing the extremely high separation efficiency of random packing, boron - 10 and boron - 11 isotopes are quickly concentrated at the top and bottom of the tower. The final products include boron - 11 isotope with an atomic abundance of up to 99.5% and boron - 10 isotope with more than 85%. The present invention uses cold nitrogen gas obtained by air separation liquid nitrogen vaporization or directly air - separated cold nitrogen gas as the system cold source. While effectively utilizing the cold energy of the air separation system, it greatly reduces the energy consumption level of the device system of the present invention. At the same time, dynamic equipment such as expanders is removed, saving equipment investment. Brief Description of the Drawings

[0068] Figure 1 is a schematic structural diagram of the separation device system of boron - 10 and boron - 11 isotopes provided in Embodiment 1 of the present invention;

[0069] Figure 2 is a schematic structural diagram of the boron trifluoride purification unit provided in Embodiment 1 of the present invention;

[0070] Figure 3 is a schematic structural diagram of the boron - 10 isotope negative - pressure low - temperature rectification unit provided in Embodiment 1 of the present invention;

[0071] Figure 4 is a schematic structural diagram of the air - separated nitrogen supply unit provided in Embodiment 1 of the present invention;

[0072] Figure 5 is a schematic structural diagram of the boron-10 isotope filling unit provided in Embodiment 1 of the present invention;

[0073] Figure 6 is a schematic structural diagram of the boron-11 isotope filling unit provided in Embodiment 1 of the present invention;

[0074] Figure 7 is a schematic structural diagram of the ultra-high purity boron trifluoride filling unit provided in Embodiment 1 of the present invention;

[0075] Figure 8 is a schematic structural diagram of the vacuum pumping system provided in Embodiment 1 of the present invention.

[0076] Wherein: 1, boron trifluoride cold trap; 2, boron trifluoride adsorption film; 3, boron trifluoride mass flow controller; 4, boron trifluoride manometer; 5, heat insulation cotton; 6, boron trifluoride stop valve; 7, slag discharge stop valve; 8, structured packing tower; 9, random packing tower; 10, electric heater; 11, condenser; 12, top pressure gauge; 13, exhaust regulating valve; 14, boron trifluoride purification tower; 15, boron-10 isotope liquefaction collector; 16, air-bath vaporizer; 17, cold source nitrogen regulating valve; 18, cold source nitrogen manometer; 19, air separation liquid nitrogen stop valve; 20, air separation nitrogen stop valve; 21, first double-temperature flexible coiled tube; 22, boron-10 filling mass flow controller; 23, boron-10 filling milligram-level electronic balance; 24, boron-11 isotope liquid collector; 25, second double-temperature flexible coiled tube; 26, boron-11 filling mass flow controller; 27, boron-11 filling gram-level electronic balance; 28, boron-11 isotope liquid stop valve; 29, first heating nitrogen stop valve; 30, first vaporization manometer; 31, boron-11 isotope gas breather valve; 32, boron trifluoride liquefaction collector; 33, third double-temperature flexible coiled tube; 34, ultra-high purity boron trifluoride liquid stop valve; 35, second heating nitrogen stop valve; 36, second vaporization manometer; 37, ultra-high purity boron trifluoride gas breather valve; 38, system vacuum pumping panel; 39, vacuum resistance gauge; 40, vacuum pumping diaphragm valve; 41, rotary vane vacuum pump; 42, muffler; 43, check valve. Specific Embodiments

[0077] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0078] Embodiment 1

[0079] This embodiment provides a separation device system for boron-10 and boron-11 isotopes, and the schematic structural diagram is as shown in Figure 1As shown, the separation device system includes a boron trifluoride purification unit, a boron-10 isotope negative-pressure low-temperature rectification unit, and a boron-10 isotope filling unit that are connected in sequence along the material flow direction; the boron-10 isotope negative-pressure low-temperature rectification unit is connected to an air separation nitrogen supply unit.

[0080] The structural schematic diagram of the boron trifluoride purification unit is as Figure 2 shown. The boron trifluoride purification unit includes a boron trifluoride cold trap 1, a boron trifluoride adsorption membrane 2, a boron trifluoride mass flow controller 3, and a boron trifluoride pressure gauge 4 that are arranged in sequence along the material flow direction; a heat-insulating cotton 5 is arranged inside the boron trifluoride cold trap 1; a boron trifluoride stop valve 6 is arranged on the pipeline before the boron trifluoride cold trap 1, and the boron trifluoride cold trap is connected to a slag discharge stop valve 7.

[0081] The structural schematic diagram of the boron-10 isotope negative-pressure low-temperature rectification unit is as Figure 3 shown. The boron-10 isotope negative-pressure low-temperature rectification unit includes a 2-stage structured packing tower 8 and a 6-stage dumped packing tower 9 arranged in series. Structured packing is arranged in the structured packing tower 8, and dumped Heli-pak packing is arranged in the dumped packing tower; electric heaters 10 are independently arranged at the bottoms of the structured packing tower 8 and the dumped packing tower 9 respectively, and condensers 11 are independently arranged at the tops respectively; a top pressure gauge 12 is independently arranged at the top of each stage of the structured packing tower 8 and the dumped packing tower 9; an exhaust regulating valve 13 is arranged at the top of each stage of the structured packing tower 8; a boron trifluoride purification tower 14 is connected before the first-stage dumped packing tower 9 in the dumped packing tower 9, and a boron-10 isotope liquefaction collector 15 is connected after the last-stage dumped packing tower 9; the bottom of the structured packing tower 8 is connected to an ultra-high purity boron trifluoride filling unit, and the bottom of the dumped packing tower 9 is connected to a boron-11 isotope filling unit.

[0082] The structural schematic diagram of the air separation nitrogen supply unit is as Figure 4 shown. The air separation nitrogen supply unit includes an air-bath vaporizer 16, a cold-source nitrogen regulating valve 17, and a cold-source nitrogen pressure gauge 18 that are connected in sequence along the material flow direction; the inlet of the air-bath vaporizer 16 is connected to an air separation liquid nitrogen pipeline and an air separation nitrogen pipeline. An air separation liquid nitrogen stop valve 19 is arranged on the air separation liquid nitrogen pipeline, and an air separation nitrogen stop valve 20 is arranged on the air separation nitrogen pipeline.

[0083] The structural schematic diagram of the boron-10 isotope filling unit is as Figure 5 shown. The boron-10 isotope filling unit includes a boron-10 isotope liquefaction collector 15, a first-stage double-temperature flexible coiled tube 21, a boron-10 filling mass flow controller 22, and a boron-10 filling milligram-level electronic balance 23 that are connected in sequence along the material flow direction; a heater is arranged at the bottom of the boron-10 isotope liquefaction collector 15, and the heater is used for vaporizing and pressurizing the boron-10 isotope liquid.

[0084] The structural schematic diagram of the boron-11 isotope filling unit is as follows Figure 6 shown. The boron-11 isotope filling unit includes a boron-11 isotope liquid collector 24, a second flexible warming coil 25, a boron-11 filling mass flow controller 26, and a boron-11 filling gram-level electronic balance 27, which are connected in sequence along the material flow direction; the inlet of the boron-11 isotope liquid collector 24 is connected to a boron-11 isotope liquid pipeline and a first heated nitrogen pipeline, and the heated nitrogen introduced into the first heated nitrogen pipeline serves as the heat source for vaporization and pressurization; a boron-11 isotope liquid stop valve 28 is provided on the boron-11 isotope liquid pipeline, and a first heated nitrogen stop valve 29 is provided on the first heated nitrogen pipeline; the boron-11 isotope liquid collector 24 is provided with a first vaporization pressure gauge 30 and a boron-11 isotope gas breather valve 31.

[0085] The structural schematic diagram of the ultra-high purity boron trifluoride filling unit is as follows Figure 7 shown. The ultra-high purity boron trifluoride filling unit includes a boron trifluoride liquefaction collector 32 and a third flexible warming coil 33, which are connected in sequence along the material flow direction; the inlet of the boron trifluoride liquefaction collector 32 is connected to an ultra-high purity boron trifluoride liquid pipeline and a second heated nitrogen pipeline, and the heated nitrogen introduced into the second heated nitrogen pipeline serves as the heat source for vaporization and pressurization; an ultra-high purity boron trifluoride liquid stop valve 34 is provided on the ultra-high purity boron trifluoride liquid pipeline, and a second heated nitrogen stop valve 35 is provided on the second heated nitrogen pipeline; the boron trifluoride liquefaction collector 32 is provided with a second vaporization pressure gauge 36 and an ultra-high purity boron trifluoride gas breather valve 37.

[0086] The separation device system is provided with a vacuum pumping system and a PLC control system; the structural schematic diagram of the vacuum pumping system is as follows Figure 8As shown, the vacuum system includes a system vacuum panel 38, which is successively connected with a vacuum resistance gauge 39, a vacuum diaphragm valve 40, a rotary vane vacuum pump 41, a muffler 42, and a check valve 43; the PLC control system controls the delivery volume of purified boron trifluoride raw material gas, and accumulates the actual usage amount of boron trifluoride raw material gas through a boron trifluoride mass flow controller 3; the PLC control system controls the power of the electric heater 10 of the boron-10 isotope negative-pressure low-temperature rectification unit, so as to control the actual evaporation amount in the structured packing tower 8 and the random packing tower 9; the PLC control system controls the cold source nitrogen flow rate, adjusts the system cold energy input, and controls the boron trifluoride condensation amount in the condenser 11; the PLC control system controls the boron-10 filling mass flow controller 22, so as to adjust the gas flow rate of the boron-10 isotope product gas and accumulate the actual filling amount of the product; the PLC control system controls the boron-11 filling mass flow controller 26, so as to adjust the gas flow rate of the boron-11 isotope product gas and accumulate the actual filling amount of the product; the PLC control system controls the exhaust regulating valves of the first-stage and last-stage structured packing towers 8 to adjust the boron-10 isotope gas outlet amount at the top of the tower; the trigger signal of the vacuum resistance gauge 39 is fed back to the PLC control system, and the control system controls the opening and closing of the vacuum diaphragm valve 40.

[0087] The separation of boron-10 and boron-11 isotopes is carried out through the separation device system, and the separation method includes the following steps:

[0088] Industrial boron trifluoride gas is successively subjected to purification treatment and negative-pressure low-temperature rectification treatment at 70 KPaA and -105.8 °C to obtain boron-10 isotope product gas, boron-11 isotope liquid, and ultra-high-purity boron trifluoride liquid; the obtained boron-10 isotope product gas is liquefied and accumulated and then subjected to the first vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then metered and filled; the obtained boron-11 isotope liquid is introduced into heated nitrogen for the second vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then metered and filled; the obtained ultra-high-purity boron trifluoride liquid is introduced into heated nitrogen for the third vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then subjected to partial pressure filling.

[0089] The purification treatment includes successively removing impurities by normal-pressure liquid nitrogen bath to make the content of high-boiling-point impurities 200 ppm, removing impurities by membrane adsorption at -70 °C to make the content of low-boiling-point impurities 2 ppm, and deep purification at -185 °C; the temperature of the first vaporization and pressurization treatment is -50 °C, and the pressure is 240 KPa; the temperature of the second vaporization and pressurization treatment is -55 °C, and the pressure is 240 KPa; the temperature of the third vaporization and pressurization treatment is -50 °C, and the pressure is 240 KPa.

[0090] After testing, the obtained products include boron-11 isotope with an atomic abundance of 99.5% and boron-10 isotope with 85%, indicating that the separation device system provided by the present invention can effectively separate boron-11 isotope and boron-10 isotope, and at the same time effectively reduce energy consumption and equipment investment.

[0091] Example 2

[0092] This embodiment provides a separation device system for boron-10 and boron-11 isotopes. The difference from Example 1 is that except that the number of stages of the structured packing column 8 is adjusted to 1 and the number of stages of the dumped packing column 9 is adjusted to 4, the rest are the same as in Example 1.

[0093] After testing, the obtained products include boron-11 isotope with an atomic abundance of 89.7% and boron-10 isotope with 69.6%. This is because the too low number of stages of the structured packing column 8 and the dumped packing column 9 will result in the separation not reaching the design effect.

[0094] Example 3

[0095] This embodiment provides a separation device system for boron-10 and boron-11 isotopes. The difference from Example 1 is that a boron trifluoride purification tower 14 is not provided before the first-stage dumped packing column 9 in the dumped packing column 9, and the rest are the same as in Example 1.

[0096] After testing, the obtained products include boron-11 isotope with an atomic abundance of 90.6% and boron-10 isotope with 73.5%. This is because the absence of the boron trifluoride purification tower will increase the impurity content in the boron trifluoride gas, which will in turn have an adverse effect on the separation of boron-11 isotope and boron-10 isotope.

[0097] Example 4

[0098] This embodiment provides a separation device system for boron-10 and boron-11 isotopes. By using the separation device system to separate boron-10 and boron-11 isotopes, the difference in the separation method from Example 1 is that except that the temperature of the vacuum low-temperature rectification treatment is adjusted to -100°C and the pressure is adjusted to 99.8 KPaA, the rest are the same as in Example 1.

[0099] After testing, the obtained products include boron-11 isotope with an atomic abundance of 84.9% and boron-10 isotope with 63.7%. This is because the too high temperature and pressure of the vacuum low-temperature rectification treatment will result in a poor rectification effect.

[0100] Comparative Example 1

[0101] This comparative example provides a separation device system for boron-10 and boron-11 isotopes. The difference from Example 1 is that the boron-10 isotope negative-pressure low-temperature rectification unit only sets a single random packing tower 9, and the rest are the same as in Example 1.

[0102] After testing, the obtained products include boron-11 isotope with an atomic abundance of 87.4% and boron-10 isotope with an atomic abundance of 69.1%. This is because setting only a single random packing tower will lead to a deterioration in the rectification effect.

[0103] In summary, the separation device system for boron-10 and boron-11 isotopes provided by the present invention removes high-boiling and low-boiling impurities in industrial boron trifluoride gas through the boron trifluoride purification unit. The production of boron-10 and boron-11 isotope products adopts a series cascade tower form. The front cascade is a series connection of structured packing towers, which can process a large amount of boron trifluoride raw material gas and provide a stable and reliable primary boron-10 raw material gas for subsequent enrichment and concentration. The back cascade is a series connection of random packing towers. Using the ultra-high separation efficiency of random packing, boron-10 and boron-11 isotopes are quickly concentrated at the top and bottom of the tower. The finally obtained products include boron-11 isotope with an atomic abundance of 99.5% and boron-10 isotope with an atomic abundance of more than 85%. The present invention uses cold nitrogen gas obtained by air separation liquid nitrogen vaporization or directly air separation cold nitrogen gas as the system cold source, effectively utilizes the cold energy of the air separation system, greatly reduces the energy consumption level of the device system of the present invention, and at the same time removes dynamic equipment such as expanders, saving equipment investment.

[0104] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of within the technical scope disclosed by the present invention fall within the protection scope and public scope of the present invention.

Claims

1. A boron 10 and boron 11 isotope separation device system, characterized in that: The separation device system comprises a boron trifluoride purification unit, a boron 10 isotope negative pressure cryogenic distillation unit and a boron 10 isotope filling unit which are sequentially connected along the material flow direction; the boron 10 isotope negative pressure cryogenic distillation unit is connected to an air separation nitrogen supply unit; The boron 10 isotope negative pressure low-temperature distillation unit comprises a structured packing tower and a random packing tower arranged in series, the bottom of the structured packing tower is connected to an ultra-high purity boron trifluoride filling unit, and the bottom of the random packing tower is connected to a boron 11 isotope filling unit; the separation device system is provided with a vacuum system and a PLC control system.

2. The separation device system according to claim 1, characterized in that: The boron trifluoride purification unit comprises a boron trifluoride cold well, a boron trifluoride adsorption membrane, a boron trifluoride mass flow controller and a boron trifluoride pressure gauge which are sequentially arranged along the material flow direction; Preferably, thermal insulation cotton is provided inside the boron trifluoride cold well.

3. The separation device system according to claim 1 or 2, characterized in that: The number of stages of the structured packing tower is ≥2, and the number of stages of the random packing tower is ≥6; Preferably, the structured packing tower is provided with structured packing, and the random packing tower is provided with random Heli-pak packing; Preferably, the structured packing tower and the random packing tower are each independently provided with an electric heater at the bottom and a condenser at the top; Preferably, a boron trifluoride purification tower is connected before the first-stage random packed tower in the random packed tower, and a boron 10 isotope liquefaction collector is connected after the last-stage random packed tower.

4. The separation device system according to any one of claims 1 to 3, characterized in that: The air separation nitrogen supply unit comprises an air bath type vaporizer, a cold source nitrogen regulating valve and a cold source nitrogen pressure gauge which are sequentially connected along the material flow direction; Preferably, the inlet of the air bath vaporizer is connected to an air separation liquid nitrogen pipeline and an air separation nitrogen gas pipeline, the air separation liquid nitrogen pipeline is provided with an air separation liquid nitrogen stop valve, and the air separation nitrogen gas pipeline is provided with an air separation nitrogen stop valve.

5. The separation device system according to any one of claims 1 to 4, characterized in that: The boron 10 isotope filling unit comprises a boron 10 isotope liquefaction collector, a first complex flexible coil, a boron 10 filling mass flow controller and a boron 10 filling electronic balance which are sequentially connected along the material flow direction; a heater is provided at the bottom of the boron 10 isotope liquefaction collector, and the heater is used for vaporization and pressurization of the boron 10 isotope liquid; Preferably, the boron 11 isotope filling unit comprises a boron 11 isotope liquid collector, a second complex flexible coil, a boron 11 filling mass flow controller and a boron 11 filling electronic balance which are sequentially connected along the material flow direction; the inlet of the boron 11 isotope liquid collector is connected to a boron 11 isotope liquid pipeline and a first heated nitrogen pipeline, and the heated nitrogen introduced into the first heated nitrogen pipeline is used as a heat source for vaporization and pressurization; Preferably, the ultra-high purity boron trifluoride filling unit comprises a boron trifluoride liquefaction collector and a third complex flexible coil connected in sequence along the material flow direction; the inlet of the boron trifluoride liquefaction collector is connected to an ultra-high purity boron trifluoride liquid pipeline and a second heated nitrogen pipeline, and the heated nitrogen introduced into the second heated nitrogen pipeline serves as a heat source for vaporization and pressurization.

6. The separation device system according to any one of claims 1 to 5, characterized in that: The vacuum pumping system comprises a system vacuum pumping panel, and the system vacuum pumping panel is sequentially connected with a vacuum resistance gauge, a vacuum pumping diaphragm valve, a rotary vane vacuum pump, a muffler and a one-way valve.

7. A method for separating boron 10 and boron 11 isotopes, characterized in that: The separation method is carried out by the boron 10 and boron 11 isotope separation device system according to any one of claims 1 to 6, and the separation method comprises the following steps: Industrial boron trifluoride gas is successively purified and subjected to negative pressure cryogenic distillation to obtain boron 10 isotope product gas, boron 11 isotope liquid and ultra-high purity boron trifluoride liquid; The obtained boron 10 isotope product gas is liquefied and accumulated, and then subjected to the first vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then metered filling; the obtained boron 11 isotope liquid is introduced into heated nitrogen for the second vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then metered filling; the obtained ultra-high purity boron trifluoride liquid is introduced into heated nitrogen for the third vaporization and pressurization treatment, and the obtained gas is reheated to room temperature and then partially pressure filled.

8. The separation method according to claim 7, characterized in that The purification treatment includes the following steps: removing impurities by atmospheric pressure liquid nitrogen bath, removing impurities by membrane adsorption and deep purification; Preferably, the end point of the atmospheric pressure liquid nitrogen bath impurity removal is to make the content of high boiling point impurities ≤500ppm; Preferably, the temperature of the membrane adsorption impurity removal is -80°C to -65°C; Preferably, the end point of the membrane adsorption impurity removal is to make the content of low boiling point impurities ≤ 6 ppm; Preferably, the temperature of the deep purification is -190°C to -180°C.

9. The separation method according to claim 7 or 8, characterized in that The pressure of the negative pressure cryogenic distillation treatment is ≤70KPaA; Preferably, the temperature of the negative pressure cryogenic distillation treatment is -106.8°C to -104.8°C.

10. The separation method according to any one of claims 7 to 9, characterized in that: The temperature of the first vaporization and pressurization treatment is -60°C to -45°C, and the pressure is 220-260KPa; Preferably, the temperature of the second vaporization and pressurization treatment is -60°C to -45°C, and the pressure is 220-260KPa; Preferably, the temperature of the third vaporization and pressurization treatment is -60°C to -45°C, and the pressure is 220-260 KPa.

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