Multi-tower series connection method and device for boron isotope separation

Abstract

The invention provides a multi-tower series connection method and device for boron isotope separation, and relates to the technical field of isotope separation. According to the multi-tower series connection method for boron isotope separation, four stages of low-temperature rectifying towers which are sequentially connected in series are adopted to achieve low-temperature rectifying separation of boron isotopes at the specific temperature and pressure, tower bottom materials of the previous stage of rectifying tower serve as feeding raw materials of the next stage of rectifying tower, and materials of all stages of rectifying towers are conveyed through pumps; after rectification of the four-stage rectifying tower, a 10BF3 product with abundance greater than 99% can be extracted from the tower bottom of the ultimate rectifying tower; and condensing the gas-phase material at the top of each stage of rectifying tower into liquid through a condenser, extracting the 11BF3 light component, and mixing and collecting the 11BF3 light component through a collecting tank. The method and the device are operated under the normal pressure condition, the boron isotope product can be continuously produced, the energy consumption is low, the production speed is high, the technological operation is simple, no side reaction exists, the product impurity is few, the purity of the boron isotope separated product can be ensured, the cost is low, and the method and the device have good industry prospects.

Description

Technical Field

[0001] The present application relates to the technical field of isotope separation, and in particular to a multi-tower series connection method and device for boron isotope separation. Background Art

[0002] Boron contains two stable isotopes in nature, boron 10 and boron 11, with natural abundances of 19.78% and 80.22%, respectively. The difference in the absorption cross-sections of boron isotopes for thermal neutrons has promoted the rapid development of research on the separation of boron isotopes. The absorption cross-section of boron 10 for thermal neutrons is more than 5 times that of naturally abundant boron, and more than 500 times that of traditional protective material concrete. Boron 10 has a wide range of applications in many technical fields due to its unique property of strong absorption of neutrons. High-abundance and high-purity boron 10 is one of the important materials in the nuclear industry (control rods, detectors and chemical control agents, etc.), military equipment (neutron protection) and the medical field (targeted treatment of cancer). And high-purity and high-abundance boron 10 is one of the important materials in the nuclear industry (control rods, detectors and chemical control agents, etc.), military equipment (neutron protection) and the medical field (targeted treatment of cancer). 11 BF3 products are widely used in chip production and can be used as raw materials for preparing optical fiber preforms in the production of semiconductor devices and integrated circuits.

[0003] At present, most of the enriched boron isotopes used in my country rely on imports, which limits the further development of my country's nuclear power, medicine and other high-tech industries, and also brings a huge economic burden. With the development and progress of modern science and technology, the demand for high-abundance boron isotope products is increasing worldwide, and the development of boron isotopes has extremely high economic value and social benefits.

[0004] At present, the most widely used boron isotope enrichment method is the boron trifluoride-complex chemical exchange method. The boron trifluoride chemical exchange distillation process using anisole as the complexing agent is currently the most widely used boron isotope enrichment method. 10 B is the most mainstream method. This process operates at normal pressure and temperature, has a high separation factor and good operating conditions. However, the production process requires strict control of the water content in the liquid phase in the tower, otherwise the generated strong acid will seriously corrode the tower equipment and the tower filler, making the entire system unable to operate. In addition, after the exchange distillation, impurities such as phenol, methyl anisole, cresol, and complexes with BF3 will be produced, which will not only cause the loss of raw material anisole, but also because these impurities are extremely difficult to crack, the viscosity of the raw material will increase as they gradually accumulate, seriously reducing the separation efficiency of the exchange reaction distillation.

[0005] Cryogenic distillation uses the slight difference in saturated vapor pressure between isotope atoms or molecules to separate isotope components. The separation of light isotope systems such as carbon is achieved through cryogenic separation technology. Research has found that 11 BF3 / 10The separation coefficient of BF3 is 1.0076. Therefore, BF3 as a separation material has the advantages of large separation factor, stable raw materials, fast separation speed, relatively short equilibrium time, etc., which is simpler to achieve large-scale industrial production. However, the existing low-temperature distillation process for separating BF3 has a too high separation tower, large engineering investment, high energy consumption, strict requirements on the purification of raw gas, automatic control instruments, equipment processing level, etc., and extremely high requirements on the insulation of the tower body, requiring strict control of temperature and pressure. Summary of the invention

[0006] The purpose of the present application is to provide a multi-tower series method and device for boron isotope separation, aiming to solve the problems of the existing chemical exchange distillation method having a simple production process, many side reactions, low production efficiency and high cost.

[0007] To achieve the above objectives, the present application provides a multi-tower series method for boron isotope separation, comprising:

[0008] Passing naturally abundant boron trifluoride into a first separation tower to perform a first cryogenic rectification enrichment to obtain a first tower top material and a first tower bottom material;

[0009] Passing the first tower bottom material into a second separation tower for second cryogenic rectification and enrichment to obtain a second tower top material and a second tower bottom material;

[0010] Passing the second tower bottom material into a third separation tower for third cryogenic rectification and enrichment to obtain a third tower top material and a third tower bottom material;

[0011] Passing the third tower bottom material into a fourth separation tower for fourth cryogenic distillation enrichment to obtain a fourth tower top material and a fourth tower bottom material, wherein the fourth tower bottom material is boron trifluoride with a boron-10 abundance greater than 99%, which is extracted as a product;

[0012] Among them, the top temperatures of the first separation tower, the second separation tower, the third separation tower and the fourth separation tower are all -97°C to -90°C, the top pressures are all 130kPa to 200kPa, the bottom temperatures are all -95°C to -83°C, and the bottom pressures are all 150kPa to 300kPa.

[0013] In some embodiments, the pressure drops of the first separation tower, the second separation tower, the third separation tower, and the fourth separation tower are 20 kPa to 100 kPa.

[0014] In some embodiments, the reflux ratio of the first cryogenic distillation is 100-1500, the reflux ratio of the second cryogenic distillation is 100-1300, the reflux ratio of the third cryogenic distillation is 200-25000, and the reflux ratio of the fourth cryogenic distillation is 400-75000.

[0015] In some embodiments, the inlet flow rate of the natural abundance boron trifluoride is 0.010kg~0.60kg, and the outlet flow rate of the first top material is 0.004kg~0.24kg; the inlet flow rate of the first bottom material is 0.006kg~0.36kg, and the outlet flow rate of the second top material is 0.004kg~0.24kg; the inlet flow rate of the second bottom material is 0.002kg~0.12kg, and the outlet flow rate of the third top material is 0.0002kg~0.012kg; the inlet flow rate of the third bottom material is 0.0018kg~0.108kg, and the outlet flow rate of the fourth top material is 0.0001kg~0.006kg; the withdrawal flow rate of the fourth bottom material is 0.0017kg~0.102kg.

[0016] In some embodiments, the purity of the natural abundance boron trifluoride is greater than 99.999%, and the boron-10 abundance is 19.78%; the first bottom material is boron trifluoride with a boron-10 abundance of about 40%; the second bottom material is boron trifluoride with a boron-10 abundance of about 60%; and the third bottom material is boron trifluoride with a boron-10 abundance of about 80%.

[0017] The present application also provides a multi-tower series device for boron isotope separation, which is used to perform the multi-tower series method for boron isotope separation, comprising a first separation tower, a second separation tower, a third separation tower and a fourth separation tower, wherein the tower bottom and the tower body are sequentially connected in series;

[0018] The first separation tower, the second separation tower, the third separation tower and the fourth separation tower are all cryogenic distillation towers, the tops of the towers are all connected to condensers, and the bottoms of the towers are all connected to reboilers;

[0019] The tops of the first separation tower, the second separation tower, the third separation tower and the fourth separation tower are respectively connected to collection tanks;

[0020] The first separation tower is provided with a raw material feed port; the bottom of the fourth separation tower is provided with a 10 BF3 products are exported.

[0021] In some embodiments, the bottom of the first separation tower is connected to the tower body of the second separation tower through a first pipeline; the bottom of the second separation tower is connected to the tower body of the third separation tower through a second pipeline; the bottom of the third separation tower is connected to the tower body of the fourth separation tower through a third pipeline; the bottom of the fourth separation tower is connected to the fourth pipeline as the 10 BF3 products are exported.

[0022] In some embodiments, the first pipeline is connected to the first reboiler, and the first reboiler is connected to the bottom of the first separation tower through a first reflux pipe; the second pipeline is connected to the second reboiler, and the second reboiler is connected to the bottom of the second separation tower through a second reflux pipe; the third pipeline is connected to the third reboiler, and the third reboiler is connected to the bottom of the third separation tower through a third reflux pipe; the fourth pipeline is connected to the fourth reboiler, and the fourth reboiler is connected to the bottom of the fourth separation tower through a fourth reflux pipe.

[0023] In some embodiments, the top of the first separation tower is connected to the collection tank via a first gas pipeline; the top of the second separation tower is connected to the collection tank via a second gas pipeline; the top of the third separation tower is connected to the collection tank via a third gas pipeline; the top of the fourth separation tower is connected to the collection tank via a fourth gas pipeline.

[0024] In some embodiments, the first gas pipeline is connected to the first condenser, and the first condenser is connected to the top of the first separation tower through a first liquid reflux pipe; the second gas pipeline is connected to the second condenser, and the second condenser is connected to the top of the second separation tower through a second liquid reflux pipe; the third gas pipeline is connected to the third condenser, and the third condenser is connected to the top of the third separation tower through a third liquid reflux pipe; the fourth gas pipeline is connected to the fourth condenser, and the fourth condenser is connected to the top of the fourth separation tower through a fourth liquid reflux pipe.

[0025] In some embodiments, the theoretical plate numbers of the first separation tower, the second separation tower, the third separation tower, and the fourth separation tower are 700 to 1200, and the tower diameters are 30 mm to 120 mm.

[0026] Compared with the prior art, the beneficial effects of this application include:

[0027] The multi-tower series method for boron isotope separation provided by the present application realizes low-temperature distillation separation of boron isotopes at specific temperature and pressure, and solves the problems of the traditional chemical exchange distillation method that the production process is not simple enough, there are many side reactions, many impurities, low production efficiency, high raw material cost, equipment corrosion, and the existing low-temperature distillation device is too high and difficult to implement in engineering; the boron isotope separation method can realize continuous production through multi-tower series connection, has a simple process, reduced energy consumption, a small number of theoretical plates, a reduced tower height, and a reduced engineering investment. 10 The abundance of BF3 is greater than 99%, and it has the advantages of high finished product yield, high production efficiency, no side reactions, low cost, and good economic efficiency, making it suitable for long-term large-scale industrial production.

[0028] The boron isotope separation method can be implemented on a set of equipment to obtain products with different boron-10 abundances. The bottoms of the four separation towers respectively obtain boron-10 isotopes with abundances of 40%, 60%, 90%, and 99%. Compared with the boron trifluoride-complex method, the raw material is only boron trifluoride, and no ether compounds are involved. The materials are simple, the product has few impurities, and the obtained 10 BF3 gas has high purity; the process is simple, the equipment is few, and the operation is simple; 10 BF3 abundance is 99% and the recovery rate of boron-10 isotope is high, reaching more than 80%.

[0029] The multi-tower series device for boron isotope separation provided in the present application comprises a first separation tower, a second separation tower, a third separation tower and a fourth separation tower, the bottom material of the previous distillation tower is used as the feed raw material of the next distillation tower, and the materials of each distillation tower are transported by a cryogenic pump. After distillation in the fourth distillation tower, the bottom of the final distillation tower can be extracted with an abundance greater than 99%. 10 BF3 product; the gaseous materials at the top of each distillation tower are condensed into liquid by the condenser and then taken out 11 The light component of BF3 is mixed and collected by the product collection tank. The device operates under normal pressure conditions and can sustainably produce boron isotope products. It has low energy consumption and fast production rate. The process operation is simple, there is no side reaction, and the product has few impurities. It can ensure the purity of the boron isotope separation product, low cost, and has a high industry prospect.

[0030] The multi-tower series process for enriching boron isotopes by cryogenic distillation proposed in the present invention uses four towers in series to gradually increase the abundance of boron 10 isotopes, which not only reduces the theoretical plate number of the distillation tower, reduces engineering investment costs and operating costs, but also greatly reduces energy consumption. In addition, the present invention effectively solves the problems of corrosion and blockage caused by cracking in the chemical exchange distillation method of boron fluoride-methyl ether complex, and has a simple process, convenient operation, low cost and high safety. The present invention proposes an innovative separation process for enriching boron isotopes in cryogenic distillation towers, which fully meets the industrial production requirements of boron isotope separation and has great industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, 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 application and therefore should not be regarded as limiting the scope of the present application.

[0032] Figure 1 This is a schematic diagram of the structure of a multi-tower series device for boron isotope separation in the present application.

[0033] Reference numerals:

[0034] 100-multi-tower series device; 10-first separation tower; 11-first pipeline; 12-first reboiler; 13-first reflux pipe; 14-first gas pipeline; 15-first condenser; 16-first liquid reflux pipe; 17-first cryogenic pump; 20-second separation tower; 21-second pipeline; 22-second reboiler; 23-second reflux pipe; 24-second gas pipeline; 25-second condenser; 26-second liquid reflux pipe; 27-second cryogenic pump; 30-third separation tower; 31-third pipeline; 32-third reboiler; 33-third reflux pipe; 34-third gas pipeline; 35-third condenser; 36-third liquid reflux pipe; 37-third cryogenic pump; 40-fourth separation tower; 41-fourth pipeline; 42-fourth reboiler; 43-fourth reflux pipe; 44-fourth gas pipeline; 45-fourth condenser; 46-fourth liquid reflux pipe; 50-collecting tank. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the invention.

[0036] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of the template are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0040] The present application provides a multi-tower series method for boron isotope separation, comprising:

[0041] S100: introducing boron trifluoride of natural abundance into a first separation tower for first cryogenic distillation enrichment to obtain a first tower top material and a first tower bottom material.

[0042] Wherein, the first separation tower is a cryogenic distillation tower, the top temperature of the first separation tower is -97°C to -90°C, for example, it can be -97°C, -96°C, -95°C, -94°C, -93°C, -92°C, -91°C or -90°C, the top pressure of the first separation tower is 130kPa to 200kPa, for example, it can be 130kPa, 140kPa, 150kPa, 160kPa, 170kPa, 180kPa, 190kPa or 200kPa, the bottom temperature of the first separation tower is -95°C to -83°C, for example, it can be -95°C, - The bottom pressure of the first separation tower is 150 kPa to 300 kPa, for example, 150 kPa, 160 kPa, 170 kPa, 180 kPa, 190 kPa, 200 kPa, 210 kPa, 220 kPa, 230 kPa, 240 kPa, 250 kPa, 260 kPa, 270 kPa, 280 kPa, 290 kPa or 300 kPa.

[0043] In some embodiments, the pressure drop of the first separation tower can be 20 kPa to 100 kPa, for example, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0044] In some embodiments, the reflux ratio of the first cryogenic distillation is 100-1500, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500 or any value between 100 and 1500.

[0045] Among them, the purity of natural abundance boron trifluoride is greater than 99.999%, the boron-10 abundance is 19.78%, the inlet flow rate of natural abundance boron trifluoride can be 0.010kg~0.60kg, the discharge flow rate of the first tower top material can be 0.004kg~0.24kg, and the first tower bottom material is boron trifluoride with a boron-10 abundance of about 40%.

[0046] S200: passing the first tower bottom material into a second separation tower for second low-temperature distillation enrichment to obtain a second tower top material and a second tower bottom material.

[0047] Wherein, the second separation tower is a cryogenic distillation tower, the top temperature of the second separation tower is -97°C to -90°C, for example, it can be -97°C, -96°C, -95°C, -94°C, -93°C, -92°C, -91°C or -90°C, the top pressure of the second separation tower is 130kPa to 200kPa, for example, it can be 130kPa, 140kPa, 150kPa, 160kPa, 170kPa, 180kPa, 190kPa or 200kPa, the bottom temperature of the second separation tower is -95°C to -83°C, for example, it can be -95°C, - The bottom pressure of the second separation tower is 150 kPa to 300 kPa, for example, it can be 150 kPa, 160 kPa, 170 kPa, 180 kPa, 190 kPa, 200 kPa, 210 kPa, 220 kPa, 230 kPa, 240 kPa, 250 kPa, 260 kPa, 270 kPa, 280 kPa, 290 kPa or 300 kPa.

[0048] In some embodiments, the pressure drop of the second separation tower can be 20 kPa to 100 kPa, for example, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0049] In some embodiments, the reflux ratio of the second cryogenic distillation is 100-1300, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300 or any value between 100 and 1300.

[0050] The inlet flow rate of the first tower bottom material is 0.006kg-0.36kg, the outlet flow rate of the second tower top material is 0.004kg-0.24kg, and the second tower bottom material is boron trifluoride with a boron-10 abundance of about 60%.

[0051] S300: The second tower bottom material is passed into a third separation tower for third low-temperature distillation enrichment to obtain a third tower top material and a third tower bottom material.

[0052] Wherein, the third separation tower is a cryogenic distillation tower, the top temperature of the third separation tower is -97°C to -90°C, for example, it can be -97°C, -96°C, -95°C, -94°C, -93°C, -92°C, -91°C or -90°C, the top pressure of the third separation tower is 130kPa to 200kPa, for example, it can be 130kPa, 140kPa, 150kPa, 160kPa, 170kPa, 180kPa, 190kPa or 200kPa, the bottom temperature of the third separation tower is -95°C to -83°C, for example, it can be -95°C, - The bottom pressure of the third separation tower is 150 kPa to 300 kPa, for example, it can be 150 kPa, 160 kPa, 170 kPa, 180 kPa, 190 kPa, 200 kPa, 210 kPa, 220 kPa, 230 kPa, 240 kPa, 250 kPa, 260 kPa, 270 kPa, 280 kPa, 290 kPa or 300 kPa.

[0053] In some embodiments, the pressure drop of the third separation tower can be 20 kPa to 100 kPa, for example, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0054] In some embodiments, the reflux ratio of the third cryogenic distillation is 200-25000, for example, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 2000, 3000, 4000, 5000, 10000, 20000, 25000 or any value between 200 and 25000.

[0055] The inlet flow rate of the second tower bottom material can be 0.002kg-0.12kg, the outlet flow rate of the third tower top material can be 0.0002kg-0.012kg, and the third tower bottom material is boron trifluoride with a boron-10 abundance of about 80%.

[0056] S400: passing the third tower bottom material into a fourth separation tower for fourth cryogenic distillation enrichment to obtain a fourth tower top material and a fourth tower bottom material, wherein the fourth tower bottom material is boron trifluoride with a boron-10 abundance greater than 99%, which is extracted as a product.

[0057] Wherein, the fourth separation tower is a cryogenic distillation tower, the top temperature of the fourth separation tower is -97°C to -90°C, for example, it can be -97°C, -96°C, -95°C, -94°C, -93°C, -92°C, -91°C or -90°C, the top pressure of the fourth separation tower is 130kPa to 200kPa, for example, it can be 130kPa, 140kPa, 150kPa, 160kPa, 170kPa, 180kPa, 190kPa or 200kPa, the bottom temperature of the fourth separation tower is -95°C to -83°C, for example, it can be -95°C, - The fourth separation tower has a bottom pressure of 150 kPa to 300 kPa, for example, 150 kPa, 160 kPa, 170 kPa, 180 kPa, 190 kPa, 200 kPa, 210 kPa, 220 kPa, 230 kPa, 240 kPa, 250 kPa, 260 kPa, 270 kPa, 280 kPa, 290 kPa or 300 kPa.

[0058] In some embodiments, the pressure drop of the fourth separation tower can be 20 kPa to 100 kPa, for example, 20 kPa, 30 kPa, 40 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa.

[0059] In some embodiments, the reflux ratio of the fourth cryogenic distillation is 400-75000, for example, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 2000, 3000, 4000, 5000, 10000, 20000, 25000, 30000, 40000, 50000, 60000, 70000, 75000 or any value between 400 and 75000.

[0060] Among them, the inlet flow rate of the third tower bottom material can be 0.0018kg~0.108kg, the discharge flow rate of the fourth tower top material can be 0.0001kg~0.006kg; the withdrawal flow rate of the fourth tower bottom material can be 0.0017kg~0.102kg.

[0061] The boron isotope separation method provided by the present application realizes low-temperature distillation separation of boron isotopes at a specific temperature and pressure, and solves the problems of the traditional chemical exchange distillation method having a simple production process, many side reactions, many impurities, low production efficiency, high raw material cost, equipment corrosion, and the existing low-temperature distillation device being too high and difficult to implement in engineering; the boron isotope separation method can realize continuous production through multiple towers in series, has a simple process, reduced energy consumption, a small number of theoretical plates, a reduced tower height, and a reduced engineering investment, and the obtained 10 The abundance of BF3 is greater than 99%, and it has the advantages of high finished product yield, high production efficiency, no side reactions, low cost, and good economic efficiency, making it suitable for long-term large-scale industrial production.

[0062] The boron isotope separation method can be implemented on a set of equipment to obtain products with different boron-10 abundances. The bottoms of the four separation towers respectively obtain boron-10 isotopes with abundances of 40%, 60%, 90%, and 99%. Compared with the boron trifluoride-complex method, the raw material is only boron trifluoride, and no ether compounds are involved. The materials are simple, the product has few impurities, and the obtained 10 BF3 gas has high purity; the process is simple, the equipment is few, and the operation is simple; 10 BF3 abundance is 99% and the recovery rate of boron-10 isotope is high, reaching more than 80%.

[0063] The present application also provides a multi-tower series device 100 for boron isotope separation, which is used to perform the above-mentioned boron isotope separation method. Figure 1 , including a first separation tower 10, a second separation tower 20, a third separation tower 30 and a fourth separation tower 40, which are connected in series in sequence; the first separation tower 10, the second separation tower 20, the third separation tower 30 and the fourth separation tower 40 are all low-temperature distillation towers.

[0064] Cryogenic distillation uses the slight difference in saturated vapor pressure between isotope atoms or molecules to separate isotope components. 11 BF3 / 10 The separation factor of BF3 is 1.0076. Therefore, BF3 as a separation material has the advantages of large separation factor, stable raw materials, fast separation speed, relatively short equilibrium time, etc., which is easier to achieve large-scale industrial production. Since the separation factor is only 1.0076, the separation of boron isotopes is difficult to complete through a single-stage distillation tower, and must rely on multi-tower cascade technology.

[0065] The tops of the first separation tower 10, the second separation tower 20, the third separation tower 30 and the fourth separation tower 40 are all connected to a condenser, and the bottoms are all connected to a reboiler; the tops of the first separation tower 10, the second separation tower 20, the third separation tower 30 and the fourth separation tower 40 are respectively connected to a collecting tank 50; the first separation tower 10 is provided with a raw material feed port; the bottom of the fourth separation tower 40 is provided with a 10 BF3 products are exported.

[0066] The multi-tower series device 100 for boron isotope separation provided in the present application uses the bottom material of the previous distillation tower as the feed material of the next distillation tower. The materials of each distillation tower are transported by a cryogenic pump, which is arranged in the middle of the pipeline connecting two adjacent distillation towers. After distillation in the fourth distillation tower, the bottom of the final distillation tower can be extracted with qualified quality. 10 Product B: The gaseous materials at the top of each distillation tower are condensed into liquid by the condenser and then taken out 11 B light components are mixed and collected by the product collection tank. The device operates under normal pressure conditions and can sustainably produce boron isotope products. It has low energy consumption and fast production rate. The process operation is simple, there is no side reaction, and the product has few impurities. It can ensure the purity of the raw gas for boron isotope separation, low cost, and has a high industry prospect.

[0067] The structure of a distillation tower generally includes a tower top at the top, a tower body in the middle, and a tower kettle at the bottom; the reboiler heats the kettle liquid to boiling, providing a certain flow of rising steam, and at the same time part of the kettle liquid is produced as the tower kettle product; the condenser condenses the rising steam entering the tower top, and part of the condensate flows into the tower as reflux liquid, and part is produced as the tower top product.

[0068] The refrigeration cycle system of the condenser uses liquid nitrogen as a refrigerant to provide the cooling capacity required for condensing BF3 gas. 11 BF3 and 10 The molar purities of BF3 were 19.78% and 80.22%, respectively.

[0069] In some embodiments, please refer to Figure 1 The bottom of the first separation tower 10 is connected to the tower body of the second separation tower 20 through a first pipeline 11; the bottom of the second separation tower 20 is connected to the tower body of the third separation tower 30 through a second pipeline 21; the bottom of the third separation tower 30 is connected to the tower body of the fourth separation tower 40 through a third pipeline 31; the bottom of the fourth separation tower 40 is connected to the fourth pipeline 41 as the 10 BF3 products are exported.

[0070] The bottom material of the first separation tower 10 is transported to the second separation tower 20 as raw material through the first pipeline 11, the bottom material of the second separation tower 20 is transported to the third separation tower 30 as raw material through the second pipeline 21, and the bottom material of the third separation tower 30 is transported to the fourth separation tower 40 as raw material through the third pipeline 31. After distillation in the four-stage distillation tower, the boron 10 product of qualified quality can be extracted from the bottom of the final distillation tower.

[0071] In some embodiments, please refer to Figure 1 The bottom material of the first separation tower 10 can be extracted as 40% abundance 10 The BF3 product can also be transported to the second separation tower 20 through the first pipeline 11 by the first cryogenic pump 17 as a separation raw material; the bottom material of the second separation tower 20 can be extracted as 60% abundance 10 The BF3 product can also be transported to the third separation tower 30 through the second pipeline 21 by the second cryogenic pump 27 as a separation raw material; the bottom material of the third separation tower 30 can be extracted as 90% abundance 10 The BF3 product can also be transported to the fourth separation tower 40 through the third pipeline 31 by the third cryogenic pump 37 as a separation raw material. Finally, the fourth separation tower 40 extracts 99% abundance of 10 BF3 products.

[0072] In some embodiments, please refer to Figure 1 The first pipeline 11 is connected to the first reboiler 12, and the first reboiler 12 is connected to the bottom of the first separation tower 10 through a first reflux pipe 13; the second pipeline 21 is connected to the second reboiler 22, and the second reboiler 22 is connected to the bottom of the second separation tower 20 through a second reflux pipe 23; the third pipeline 31 is connected to the third reboiler 32, and the third reboiler 32 is connected to the bottom of the third separation tower 30 through a third reflux pipe 33; the fourth pipeline 41 is connected to the fourth reboiler 42, and the fourth reboiler 42 is connected to the bottom of the fourth separation tower 40 through a fourth reflux pipe 43.

[0073] The reboiler heats the kettle liquid to boiling and provides a certain flow of rising steam. The rising steam returns to the kettle of the distillation tower through the reflux pipe. At the same time, part of the kettle liquid is extracted from the liquid pipeline as the kettle product.

[0074] In some embodiments, please refer to Figure 1 The top of the first separation tower 10 is connected to the collection tank 50 through a first gas pipeline 14; the top of the second separation tower 20 is connected to the collection tank 50 through a second gas pipeline 24; the top of the third separation tower 30 is connected to the collection tank 50 through a third gas pipeline 34; the top of the fourth separation tower 40 is connected to the collection tank 50 through a fourth gas pipeline 44.

[0075] In some embodiments, please refer to Figure 1 The first gas pipeline 14 is connected to the first condenser 15, and the first condenser 15 is connected to the top of the first separation tower 10 through the first liquid reflux pipe 16; the second gas pipeline 24 is connected to the second condenser 25, and the second condenser 25 is connected to the top of the second separation tower 20 through the second liquid reflux pipe 26; the third gas pipeline 34 is connected to the third condenser 35, and the third condenser 35 is connected to the top of the third separation tower 30 through the third liquid reflux pipe 36; the fourth gas pipeline 44 is connected to the fourth condenser 45, and the fourth condenser 45 is connected to the top of the fourth separation tower 40 through the fourth liquid reflux pipe 46.

[0076] The multi-tower series device 100 for boron isotope separation of the present application has a product obtained at the top of the tower, boron 11, which is separated and purified in sequence by four distillation towers. 11 Product B is in product collection tank 50 and further tested 11 The purity and yield of product B, obtained by this process 11 The purity of B is above 96%. In the first step of distillation, the bottom of the first separation tower 10 can obtain a 40% abundance 10 B; After the second distillation, the second separation tower 20 bottom can obtain an abundance of 60% 10 B; The third separation tower 30 bottom can obtain an abundance of 90% 10 B, after further separation and purification, the fourth separation tower 40 bottom can obtain an abundance of not less than 99% 10 B finished product. The multi-tower series continuous production process is simple, and the final collected tower bottom 10 The purity of product B is not less than 99% and the yield is 85%.

[0077] In some embodiments, the theoretical plate numbers of the first separation tower 10, the second separation tower 20, the third separation tower 30, and the fourth separation tower 40 are 700 to 1200, for example, 700, 800, 900, 1000, 1100, 1200 or any value between 700 and 1200.

[0078] In some embodiments, the reflux ratios of the first separation tower 10, the second separation tower 20, the third separation tower 30, and the fourth separation tower 40 are 224.84, 254, 470, and 1910, respectively.

[0079] The reflux ratio is the ratio of the reflux volume at the top of the tower to the product volume at the top of the tower. The reflux ratio is determined based on the separation requirements for the raw materials. If the reflux ratio is too large or too small, it will affect the economic efficiency of the distillation operation and the quality of the product. Increasing the reflux ratio can increase the concentration of light components in the tower top product, but it reduces the production capacity of the tower and increases the consumption of cooling capacity at the top of the tower. In normal operation, an appropriate reflux ratio should be maintained to strive for the best economic effect while ensuring product quality. The reflux ratio can only be adjusted when the normal production conditions of the tower are damaged or the product quality is unqualified.

[0080] In some embodiments, the tower diameters of the first separation tower 10, the second separation tower 20, the third separation tower 30, and the fourth separation tower 40 are 30 mm to 120 mm, for example, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm or any value between 30 mm and 120 mm.

[0081] Preferably, the tower diameter of the first separation tower 10 is greater than the tower diameter of the second separation tower 20 , the tower diameter of the third separation tower 30 , and the tower diameter of the fourth separation tower 40 .

[0082] Among the multi-stage distillation towers, the material in the front-stage distillation tower is higher than that in the rear-stage distillation tower, and the material amount is positively correlated with the tower diameter. Therefore, the tower diameter of the rear-stage distillation tower can be smaller than that of the front-stage distillation tower, thereby saving costs.

[0083] The present invention can obtain 40% of the abundance of 10 BF3, the bottom stream is transported to the second distillation tower, and after further separation and purification, the bottom of the second distillation tower can obtain 60% abundance 10 BF3; The bottom stream of the second distillation tower is transported to the third distillation tower, and after further separation and purification, the bottom of the third distillation tower can obtain 90% abundance 10 BF3; further transport the bottom stream to the fourth cryogenic distillation tower, and finally the bottom stream can obtain a product with an abundance of more than 99% and a product yield of more than 85%. 10 BF3 product. The top products of each level of distillation tower are collected by mixing tanks, and the abundance of more than 96% can be obtained. 11 BF3 products.

[0084] The existing research on the enrichment of boron isotopes by cryogenic distillation is still at the laboratory stage. Due to the technical problems of the cryogenic distillation tower being too high and the large engineering investment, large-scale industrial production has not yet been truly realized. The multi-tower series process for enriching boron isotopes by cryogenic distillation proposed in the present invention uses four towers in series to gradually increase the abundance of boron 10 isotopes, which not only reduces the theoretical plate number of the distillation tower, reduces the engineering investment cost and operating cost, but also greatly reduces energy consumption. In addition, the present invention effectively solves the problems of corrosion and blockage caused by cracking in the chemical exchange distillation of boron fluoride methyl ether complex, and the process is simple, easy to operate, low cost and high safety. The present invention proposes an innovative separation process for realizing the enrichment of boron isotopes in a cryogenic distillation tower, which fully meets the industrial production requirements of boron isotope separation and has great industrial application prospects.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0086] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A multi-tower series method for boron isotope separation, characterized in that: include: Passing naturally abundant boron trifluoride into a first separation tower to perform a first cryogenic rectification enrichment to obtain a first tower top material and a first tower bottom material; Passing the first tower bottom material into a second separation tower for second cryogenic rectification and enrichment to obtain a second tower top material and a second tower bottom material; Passing the second tower bottom material into a third separation tower for third cryogenic rectification and enrichment to obtain a third tower top material and a third tower bottom material; Passing the third tower bottom material into a fourth separation tower for fourth cryogenic distillation enrichment to obtain a fourth tower top material and a fourth tower bottom material, wherein the fourth tower bottom material is boron trifluoride with a boron-10 abundance greater than 99%, which is extracted as a product; Among them, the top temperatures of the first separation tower, the second separation tower, the third separation tower and the fourth separation tower are all -97°C to -90°C, the top pressures are all 130kPa to 200kPa, the bottom temperatures are all -95°C to -83°C, and the bottom pressures are all 150kPa to 300kPa.

2. The multi-tower series method for boron isotope separation according to claim 1, characterized in that: The pressure drops of the first separation tower, the second separation tower, the third separation tower, and the fourth separation tower are 20 kPa to 100 kPa.

3. The multi-tower series method for boron isotope separation according to claim 1, characterized in that: The reflux ratio of the first cryogenic distillation is 100-1500, the reflux ratio of the second cryogenic distillation is 100-1300, the reflux ratio of the third cryogenic distillation is 200-25000, and the reflux ratio of the fourth cryogenic distillation is 400-75000.

4. The multi-tower series method for boron isotope separation according to claim 1, characterized in that: The inlet flow rate of the natural abundance boron trifluoride is 0.010kg-0.60kg, and the outlet flow rate of the first tower top material is 0.004kg-0.24kg; the inlet flow rate of the first tower bottom material is 0.006kg-0.36kg, and the outlet flow rate of the second tower top material is 0.004kg-0.24kg; the inlet flow rate of the second tower bottom material is 0.002kg-0.12kg, and the outlet flow rate of the third tower top material is 0.0002kg-0.012kg; the inlet flow rate of the third tower bottom material is 0.0018kg-0.108kg, and the outlet flow rate of the fourth tower top material is 0.0001kg-0.006kg; the withdrawal flow rate of the fourth tower bottom material is 0.0017kg-0.102kg.

5. A multi-tower series device for boron isotope separation, used to perform the multi-tower series method for boron isotope separation according to any one of claims 1 to 4, characterized in that: It comprises a first separation tower, a second separation tower, a third separation tower and a fourth separation tower which are connected in series in sequence with a tower kettle and a tower body; The first separation tower, the second separation tower, the third separation tower and the fourth separation tower are all cryogenic distillation towers, the tops of the towers are all connected to condensers, and the bottoms of the towers are all connected to reboilers; The tops of the first separation tower, the second separation tower, the third separation tower and the fourth separation tower are respectively connected to collection tanks; The first separation tower is provided with a raw material feed port; the bottom of the fourth separation tower is provided with a 10 BF3 products are exported.

6. The multi-tower series device for boron isotope separation according to claim 5, characterized in that: The tower bottom of the first separation tower is connected to the tower body of the second separation tower through a first pipeline; the tower bottom of the second separation tower is connected to the tower body of the third separation tower through a second pipeline; the tower bottom of the third separation tower is connected to the tower body of the fourth separation tower through a third pipeline; the tower bottom of the fourth separation tower is connected to a fourth pipeline as the 10 BF3 products are exported.

7. The multi-tower series device for boron isotope separation according to claim 6, characterized in that: The first pipeline is connected to the first reboiler, and the first reboiler is connected to the kettle of the first separation tower through a first reflux pipe; the second pipeline is connected to the second reboiler, and the second reboiler is connected to the kettle of the second separation tower through a second reflux pipe; the third pipeline is connected to the third reboiler, and the third reboiler is connected to the kettle of the third separation tower through a third reflux pipe; the fourth pipeline is connected to the fourth reboiler, and the fourth reboiler is connected to the kettle of the fourth separation tower through a fourth reflux pipe.

8. The multi-tower series device for boron isotope separation according to claim 5, characterized in that: The top of the first separation tower is connected to the collection tank via a first gas pipeline; the top of the second separation tower is connected to the collection tank via a second gas pipeline; the top of the third separation tower is connected to the collection tank via a third gas pipeline; the top of the fourth separation tower is connected to the collection tank via a fourth gas pipeline.

9. The multi-tower series device for boron isotope separation according to claim 8, characterized in that: The first gas pipeline is connected to the first condenser, and the first condenser is connected to the top of the first separation tower through the first liquid reflux pipe; the second gas pipeline is connected to the second condenser, and the second condenser is connected to the top of the second separation tower through the second liquid reflux pipe; the third gas pipeline is connected to the third condenser, and the third condenser is connected to the top of the third separation tower through the third liquid reflux pipe; the fourth gas pipeline is connected to the fourth condenser, and the fourth condenser is connected to the top of the fourth separation tower through the fourth liquid reflux pipe.

10. The multi-tower series device for boron isotope separation according to any one of claims 5 to 9, characterized in that: The theoretical plate numbers of the first separation tower, the second separation tower, the third separation tower and the fourth separation tower are 700 to 1200, and the tower diameters are 30 mm to 120 mm.

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