Device and method for separating boron isotopes through direct refrigeration and low-temperature rectification

Abstract

The invention discloses a device and a method for separating boron isotopes through direct refrigeration and low-temperature rectification, and relates to the technical field of separation. The device comprises rectifying towers, a reboiler and a compressor, a liquid-phase material is discharged to the tower top of the next-stage rectifying tower through a tower kettle of each-stage rectifying tower, and a gas-phase material is discharged to the tower kettle of the previous-stage rectifying tower through the tower top of each-stage rectifying tower. Extra heat source heat supply and cold source cooling are not needed, a large amount of cooling capacity can be obtained with a small amount of power consumption, the power consumption is only about 1 / 10 of the cooling capacity required by rectification, a large amount of low-grade cooling capacity is recycled through a circulating working medium, energy is efficiently utilized, and the energy consumption of the device is reduced; and compared with other chemical exchange rectification methods, the design of a complexing process and a cracking process is omitted, further impurity removal treatment is not needed subsequently, and the technological process is simplified.

Description

Technical Field

[0001] This invention relates to the field of separation technology, and more specifically, to an apparatus and method for separating boron isotopes by direct refrigeration cryogenic distillation. Background Technology

[0002] Thirteen isotopes of boron have been discovered, while natural boron has two stable isotopes. 10 B and 11 B, with abundances of 19.8% and 80.2%, respectively. 10 B compared to 11 B has a very strong ability to absorb neutrons. 10 These excellent properties of B make it suitable for a wide range of applications in the nuclear industry. High abundance 11 Boron trifluoride gas, produced from boron (B), is used as a specialty electronic gas in the high-end semiconductor manufacturing industry. Additionally, both boron-10 and boron-11 have applications in nuclear magnetic resonance (NMR) research.

[0003] Currently, various methods for separating boron isotopes have been developed, such as the low-temperature distillation of boron trifluoride, the chemical exchange distillation of boron trifluoride, and the ion exchange method of boric acid solution. However, only the chemical exchange distillation of boron trifluoride-anisole and the chemical exchange distillation of boron trifluoride-methyl ether have truly realized the industrial production of boron isotopes.

[0004] Chemical exchange distillation is a method for separating boron isotopes based on the difference in complexing ability of gases within liquid-phase complexes. In the distillation column, a countercurrent, staged contact mass transfer between the gas and liquid phases is formed, resulting in higher affinity... 10 BF3 is enriched in liquid-phase complexes, exhibiting poor affinity. 11 BF3 accumulates in the gas phase. This method requires the complexation of raw materials, isotope exchange, and pyrolysis separation of liquid products to be carried out between different types of tower equipment, resulting in a large number of process equipment and complex process parameter control. The selection of complexes has gone through iterations from diethyl ether and methyl ether to anisole, but problems such as the need for depressurization operation in the separation process, low production capacity, and complex decomposition still exist.

[0005] Given the complexity of the above-mentioned equipment and processes, the high control requirements, the negative pressure process conditions, and the resulting decomposition losses, there is an urgent need to develop an energy-saving low-temperature distillation boron isotope purification device to reduce energy consumption, simplify the process, and control production costs.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide an apparatus and method for separating boron isotopes by direct refrigeration and cryogenic distillation.

[0008] This invention is implemented as follows: In a first aspect, the present invention provides an apparatus for direct refrigeration cryogenic distillation separation of boron isotopes, comprising a distillation column, a reboiler, and a compressor. The distillation column comprises an initial distillation column, an intermediate distillation column, and a final distillation column connected in series. The number of intermediate distillation columns is multiple and they are connected in series. One of the intermediate distillation columns is selected as the feed column. Each distillation column is provided with a bottom liquid phase pipe and a top gas phase pipe. The reboiler includes a material channel and a heating medium channel. The bottom liquid phase tube of the initial distillation column is connected to the top of the first intermediate distillation column, and so on until the bottom liquid phase tube of the last intermediate distillation column is connected to the top of the terminal distillation column. The top vapor tube of the terminal distillation column is connected to the bottom of the last intermediate distillation column, and so on until the top vapor tube of the first intermediate distillation column is connected to the bottom of the initial distillation column. The top vapor pipe of the initial distillation column is connected to the compressor, the compressor is connected to the inlet of the heating medium channel of the reboiler, and the outlet of the heating medium channel is provided with a reflux branch and a top collection branch, the reflux branch being connected to the top of the initial distillation column. The liquid phase tube at the bottom of the terminal distillation column is provided with a reboiler branch and a bottom outlet branch. The reboiler branch is connected to the material channel of the reboiler. The material channel and the heating medium channel exchange heat. The outlet of the material channel is connected to the bottom of the terminal distillation column.

[0009] In an optional embodiment, the apparatus for direct refrigeration cryogenic distillation to separate boron isotopes further includes a separator, which is connected to the outlet of the heating medium channel, and the outlet of the separator is connected to the reflux branch and the top sampling branch of the tower, respectively.

[0010] In an optional embodiment, a reflux pump is provided at the outlet of the separator, and the outlet of the reflux pump is connected to the reflux branch and the top extraction branch of the tower, respectively.

[0011] In an optional embodiment, each of the column bottom liquid phase pipes is equipped with a delivery pump.

[0012] In an optional embodiment, the intermediate distillation column has 4-6 stages.

[0013] In an optional embodiment, a heat exchanger is provided on the reflux branch for maintaining the temperature of the device for direct refrigeration cryogenic distillation to separate boron isotopes.

[0014] In an optional embodiment, the apparatus for direct cooling cryogenic distillation to separate boron isotopes is further provided with a feed pipe, on which a concentration detection module and a flow regulating valve are provided. The feed pipe is connected to multiple intermediate distillation columns through a multi-way valve. The concentration detection module is signal-connected to the multi-way valve to control the connection state of the multi-way valve, thereby adjusting the feed position. And / or, the compressor is equipped with a frequency converter module for adjusting the compressor frequency, and a purity detection mechanism is provided on the bottom outlet branch of the tower, the purity detection mechanism being signal-connected to the frequency converter module.

[0015] Secondly, the present invention provides a method for separating boron isotopes by direct refrigeration cryogenic distillation, which employs the apparatus for separating boron isotopes by direct refrigeration cryogenic distillation as described in any of the foregoing embodiments, and includes: The raw material is fed into the feed tower and, after low-temperature distillation, forms liquid and gaseous materials. The liquid material is transported through the bottom liquid phase pipe of the feed column to the top of the next intermediate distillation column for low-temperature distillation, and so on until the bottom liquid phase of the last intermediate distillation column is transported to the top of the terminal distillation column. The liquid material in the initial distillation column is transported to the top of the first intermediate distillation column, and so on until it is transported to the feed column to form a cycle. The gaseous material is transported through the gas phase pipe at the top of the feed column to the bottom of the previous intermediate distillation column for low-temperature distillation, and so on until the liquid phase of the bottom of the first intermediate distillation column is transported to the bottom of the initial distillation column; the gaseous material of the terminal distillation column is transported to the bottom of the last intermediate distillation column, and so on until it is transported to the feed column to form a cycle; The liquid material in the terminal distillation column is divided into two paths: one path is introduced into the material channel through the reboiler branch, heated by the reboiler, and then returned to the terminal distillation column; the other path is output from the reboiler through the reboiler outlet branch. The gaseous material in the initial distillation column is compressed by the compressor, heated and pressurized, and then transported to the heating medium channel of the reboiler as the heat source for the liquid material in the final distillation column input into the reboiler. The material output from the heating medium channel is divided into two paths: one path returns to the top of the initial distillation column via the reflux branch, and the other path outputs the top product via the top product branch.

[0016] In an optional embodiment, the material output from the heating medium channel is further subjected to gas-liquid separation by a separator, wherein the condensate is divided into two streams.

[0017] In an optional embodiment, the operating pressure of the initial distillation column, the intermediate distillation column, and the terminal distillation column are all controlled at 101~150 kPaA, and the operating temperature is all controlled at -101~-92℃.

[0018] In an optional implementation, the reflux ratio of the reflux branch and the tower top extraction branch is 150~2000.

[0019] In an optional embodiment, the raw material includes naturally abundant boron trifluoride or boron trifluoride that has been separated and enriched. And / or, the feed state of the raw material includes gas phase, liquid phase or gas-liquid mixture.

[0020] The present invention has the following beneficial effects: The apparatus for direct-refrigeration cryogenic distillation separation of boron isotopes provided by this invention utilizes multi-stage distillation columns 110 to separate isotopes from the raw material, establishing a continuous and stable concentration gradient. Simultaneously, the liquid phase material is discharged from the bottom of each stage of distillation column 110 to the top of the next stage, while the gaseous phase material is discharged from the top of each stage of distillation column 110 to the bottom of the previous stage, thus achieving downward flow of the liquid phase and upward flow of the gas phase, forming counter-current convection. The gas and liquid phases are in full contact within the column, and the target isotope repeatedly transfers between the two phases, improving separation accuracy. Each stage of distillation column 110 undertakes the separation task within a specific concentration range. The liquid phase carries heavy components (or target isotopes) to the lower-level column for further purification, while the gas phase carries light components to the upper-level column for enrichment. This gradually increases the concentration difference between the components and impurities, thereby achieving the gradual enrichment of the target components and ultimately separating boron isotopes. Simultaneously, this invention utilizes the heat released from the pressurized and heated gas phase at the top of the column to heat the reboiler 120, eliminating the need for additional heat sources and cooling sources. A large amount of cooling capacity is obtained with minimal electricity consumption, requiring only about 1 / 10 of the cooling capacity required for distillation. A significant amount of low-grade cooling capacity is recovered and reused through a circulating working fluid, maximizing energy efficiency and reducing equipment energy consumption. Compared to other chemical exchange distillation methods, this method eliminates the need for complexation and cracking processes, and subsequent impurity removal is also unnecessary, simplifying the process flow. Furthermore, high abundance is obtained at the top of the column during distillation separation. 11 BF3, high abundance at the base of the tower. 10 BF3. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the structure of the apparatus for direct refrigeration cryogenic distillation separation of boron isotopes provided by the present invention; Figure 2 This is a schematic diagram of the structure of the direct refrigeration cryogenic distillation apparatus for separating boron isotopes provided by the present invention, with a multi-port valve for adjusting the feed position.

[0023] Icons: 100 - Device for direct refrigeration cryogenic distillation separation of boron isotopes; 110 - Distillation column; 111 - Initial distillation column; 112 - Intermediate distillation column; 1121 - Feed column; 113 - Terminal distillation column; 114 - Bottom liquid phase pipe; 115 - Top vapor phase pipe; 116 - Transfer pump; 120 - Reboiler; 121 - Material channel; 122 - Heating medium channel; 130 - Compressor; 140 - Separator; 141 - Reflux pump; 150 - Reflux branch; 151 - Heat exchanger; 160 - Top outlet branch; 170 - Reboiler branch; 180 - Bottom outlet branch; 190 - Feed pipe; 191 - Concentration detection module; 192 - Flow regulating valve; 193 - Multi-port valve. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] Please see Figure 1This invention provides an apparatus 100 for direct refrigeration cryogenic distillation separation of boron isotopes, comprising a distillation column 110, a reboiler 120, and a compressor 130. The distillation column 110 includes an initial distillation column 111, intermediate distillation columns 112, and a final distillation column 113 connected in series. Multiple intermediate distillation columns 112 are connected in series, and one of the intermediate distillation columns 112 is selected as the feed column 1121. Each distillation column 110 is equipped with a bottom liquid phase pipe 114 and a top vapor phase pipe 115. The reboiler 120 includes a material channel 121 and a heating medium channel. The bottom liquid phase pipe 114 of the initial distillation column 111 is connected to the top of the first intermediate distillation column 112, and so on until the bottom liquid phase pipe 114 of the last intermediate distillation column 112 is connected to the top of the final distillation column 113. The top vapor phase of the final distillation column 113... Pipe 115 is connected to the bottom of the last intermediate distillation column 112, and so on until the top vapor pipe 115 of the first intermediate distillation column 112 is connected to the bottom of the initial distillation column 111; the top vapor pipe 115 of the initial distillation column 111 is connected to the compressor 130, the compressor 130 is connected to the inlet of the heating medium channel of the reboiler 120, the outlet of the heating medium channel is provided with a reflux branch 150 and a top outlet branch 160, the reflux branch 150 is connected to the top of the initial distillation column 111; the bottom liquid pipe 114 of the final distillation column 113 is provided with a reboiler branch 170 and a bottom outlet branch 180, the reboiler branch 170 is connected to the material channel 121 of the reboiler 120, the material channel 121 and the heating medium channel exchange heat, and the outlet of the material channel 121 is connected to the bottom of the final distillation column 113.

[0026] In this invention, a multi-stage distillation column 110 is used to separate the isotopes of the raw material. The raw material enters from the feed column 1121, which is located in one of the intermediate distillation columns 112. By using a mid-stage feed, the separation efficiency can be maximized, energy consumption reduced, and product purity optimized. This is because when multiple columns are connected in series, each column has already formed a target isotope concentration distribution from low to high. The concentration of the mid-stage column is closer to the target isotope concentration in the raw material, and the feed will not disrupt the existing gradient equilibrium. If the feed is from the first column (low concentration end), a large amount of raw material needs to be gradually enriched from the initial low concentration, which will significantly increase the separation pressure and energy consumption of the preceding columns. Mid-stage feed can directly connect to the corresponding concentration level, shortening the separation path. In addition, the distillate or bottom liquid concentration of the first column is extremely low, and direct feed may dilute the intermediate product. Mid-stage feed can reduce the ineffective mixing of materials of different concentrations and ensure the stability of the product purity of each column.

[0027] Due to the inherent difficulty of isotope separation (isotopes have very similar physicochemical properties), the core of multi-tower series connection is to construct a continuous and stable concentration gradient. The central feed is essentially an optimized design of "cross-flow feed," which utilizes the established separation foundation and balances the gas-liquid load of each tower, allowing the entire system to operate efficiently and collaboratively.

[0028] In this invention, raw materials are distilled at low temperature to form liquid and gaseous phases. The liquid phase is discharged from the bottom of each distillation column 110 to the top of the next distillation column 110, while the gaseous phase is discharged from the top of each distillation column 110 to the bottom of the previous distillation column 110. This achieves downward flow of the liquid phase and upward flow of the gas phase, forming countercurrent convection. The gas and liquid phases are in full contact within the columns, and the target isotope is repeatedly transferred between the two phases, improving separation accuracy. Each distillation column 110 is responsible for separating a specific concentration range. The liquid phase carries heavier components (or target isotopes) to the next column for further purification, while the gas phase carries lighter components to the next column for enrichment, gradually increasing the concentration difference between components and impurities, thereby gradually enriching the target component. Furthermore, the countercurrent flow keeps the gas-liquid load and concentration distribution of each column balanced. This avoids localized concentration fluctuations caused by unidirectional flow, ensuring continuous and stable separation in the multi-column series system and reducing energy consumption.

[0029] Furthermore, the apparatus 100 for direct refrigeration cryogenic distillation to separate boron isotopes also includes a separator 140, which is connected to the outlet of the heating medium channel. The outlet of the separator 140 is connected to a reflux branch 150 and a top product branch 160, respectively. A reflux pump 141 is installed at the outlet of the separator 140, and the outlet of the reflux pump 141 is connected to both the reflux branch 150 and the top product branch 160, respectively.

[0030] In this invention, the material discharged from the heating medium channel is further separated by the separator 140. At the same time, the separator 140 can also be used as a buffer tank to prevent the material discharged from the heating medium channel from directly contacting the return pump 141, which would cause large fluctuations and affect the return pump 141.

[0031] In this invention, each column bottom liquid phase pipe 114 is equipped with a transfer pump 116, which is used only to overcome the liquid column pressure at the column height.

[0032] The number of stages in the intermediate distillation column 112 can be determined according to the separation requirements. The present invention provides a typical but non-limiting example: the intermediate distillation column 112 has 4-6 stages, that is, the distillation column 110 has 6-8 stages in total, and the feed column 1121 can be selected from the distillation column 110 located in the 4-6 stage as the feed site.

[0033] Furthermore, the reflux branch 150 of the present invention is provided with a heat exchanger 151 for maintaining the temperature (-101~-92°C) of the device 100 for direct refrigeration low-temperature distillation separation of boron isotopes. At least one of nitrogen, methane and ethylene refrigerant can be used in the heat exchanger 151 to maintain the low temperature state of the system.

[0034] In addition, please see Figure 2 The apparatus 100 for direct refrigeration cryogenic distillation separation of boron isotopes of the present invention is further provided with a feed pipe 190. The feed pipe 190 is provided with a concentration detection module 191 and a flow regulating valve 192. The feed pipe 190 is connected to multiple intermediate distillation columns 112 through a multi-way valve 193. The concentration detection module 191 is signal-connected to the multi-way valve 193 to control the connection state of the multi-way valve 193, thereby adjusting the feed position. In the present invention, the concentration detection module 191 is used to realize the target isotope concentration in the raw material and automatically adjust the feed position (which can be switched between multiple intermediate distillation columns 112), thereby achieving matching of the concentration gradient of multiple columns and solving the problem of decreased separation efficiency of the fixed feed column 1121 when facing raw material fluctuations.

[0035] Furthermore, the compressor 130 is equipped with a frequency converter (not shown) for adjusting the frequency of the compressor 130, and a purity detection mechanism (not shown) is installed on the reboiler outlet branch 180. The purity detection mechanism is connected to the frequency converter module. This invention can dynamically adjust the pressure and temperature parameters of the compressor 130 based on the purity feedback of the product from the reboiler of the terminal distillation column 113, so that the heating load of the reboiler 120 matches the separation requirements in real time, avoiding excessive energy consumption or insufficient heating, and improving the system's adaptability and energy-saving stability.

[0036] Furthermore, the present invention provides a method for separating boron isotopes by direct refrigeration cryogenic distillation, which employs the aforementioned apparatus 100 for separating boron isotopes by direct refrigeration cryogenic distillation, and includes: The raw material is fed into the feed tower 1121 and, after low-temperature distillation, forms liquid and gaseous materials. The liquid material is transported through the bottom liquid phase pipe 114 of the feed column 1121 to the top of the next intermediate distillation column 112 for low-temperature distillation, and so on until the bottom liquid phase of the last intermediate distillation column 112 is transported to the top of the terminal distillation column 113. The liquid material in the initial distillation column 111 is transported to the top of the first intermediate distillation column 112, and so on until it is transported to the feed column 1121 to form a cycle. The gaseous material is conveyed through the gas phase pipe 115 at the top of the feed column 1121 to the bottom of the previous intermediate distillation column 112 for low-temperature distillation, and so on until the liquid phase of the bottom of the first intermediate distillation column 112 is conveyed to the bottom of the initial distillation column 111; the gaseous material of the final distillation column 113 is conveyed to the bottom of the last intermediate distillation column 112, and so on until it is conveyed into the feed column 1121 to form a cycle; The liquid material in the terminal distillation column 113 is divided into two paths. One path is passed through the reboiler branch 170 into the material channel 121, heated by the reboiler 120, and then returned to the terminal distillation column 113. The other path is output through the column bottom outlet branch 180. The gaseous material in the initial distillation column 111 is compressed by the compressor 130, heated and pressurized, and then transported to the heating medium channel of the reboiler 120 as the heat source for the liquid material in the final distillation column 113 input into the reboiler 120. The material output from the heating medium channel is divided into two paths: one path returns to the top of the initial distillation column 111 via the reflux branch 150, and the other path outputs the top product via the top product branch 160.

[0037] The material output from the heating medium channel is further separated into gas and liquid by separator 140, with the condensate being divided into two streams.

[0038] In this invention, the operating pressure of the initial distillation column 111, the intermediate distillation column 112, and the terminal distillation column 113 are all controlled at 101~150 kPaA, and the operating temperature is controlled at -101~-92℃.

[0039] The reflux ratio of reflux branch 150 and top product branch 160 is 150~2000. Here, "reflux ratio" refers to the ratio of the amount of material returned to the tower to the amount of product produced. The reflux liquid is the liquid phase material condensed at the top of the tower, which is returned to the tower to participate in gas-liquid contact.

[0040] In this invention, by adjusting the reflux ratio to 150~2000, it is beneficial to adjust the separation accuracy. The larger the reflux ratio, the more sufficient the gas-liquid contact in the column, the more thorough the component separation, and the higher the product purity. A suitable reflux ratio can maintain the stability of the gas-liquid load in the column, avoid abnormal operating conditions such as flooding and leakage, and ensure the continuous and stable operation of the distillation column 110.

[0041] Since increasing the reflux ratio requires more condensation and reboiling energy consumption, this application uses compressor 130 to heat and pressurize the gaseous material in the initial distillation column 111, and uses the material discharged from compressor 130 as the heat source of reboiler 120 to exchange heat with the liquid material in the final distillation column 113 introduced into reboiler 120. No additional heat source is required for heating and cold source for cooling, which significantly reduces energy consumption. Therefore, the reflux ratio can be increased with low energy consumption.

[0042] Furthermore, the raw materials provided by this invention include naturally abundant boron trifluoride or boron trifluoride after separation and enrichment; and / or, the feed state of the raw materials includes gas phase, liquid phase or gas-liquid mixture.

[0043] The apparatus 100 and method for direct refrigeration cryogenic distillation separation of boron isotopes provided by this invention can achieve the separation of boron isotopes, wherein a high abundance is obtained at the top of the distillation column during the distillation separation. 11 BF3, high abundance at the base of the tower. 10 BF3. Due to the use of 11 BF3 and 10 BF3 has a very small boiling point difference, resulting in a minimal temperature difference between the top and bottom of distillation column 110. Simultaneously, the heat of condensation at the top and the heat source required at the bottom are comparable. This invention utilizes the heat released from the condensation of the pressurized and heated vapor phase at the top of the column to heat the reboiler 120. No additional heat source or cooling source is needed; a large amount of cooling capacity can be obtained with minimal electricity consumption, requiring only about 1 / 10 of the cooling capacity required for distillation. A significant amount of low-grade cooling capacity is recovered and reused through a circulating working fluid, efficiently utilizing energy and reducing equipment energy consumption. Compared to other chemical exchange distillation methods, it eliminates the need for complexation and cracking processes, and subsequent impurity removal is also unnecessary, simplifying the process flow.

[0044] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0045] Example 1 This embodiment provides an apparatus 100 for direct refrigeration cryogenic distillation to separate boron isotopes, which includes a distillation column 110, a reboiler 120, a compressor 130, and a separator 140.

[0046] The distillation column 110 consists of seven stages, including an initial distillation column 111, five intermediate distillation columns 112, and a final distillation column 113 connected in series. The fourth stage column is selected as the feed column 1121. Each distillation column 110 is equipped with a bottom liquid phase pipe 114 and a top vapor phase pipe 115. Each bottom liquid phase pipe 114 is equipped with a transfer pump 116. The reboiler 120 includes a material channel 121 and a heating medium channel. The bottom liquid phase pipe 114 of the initial distillation column 111 is connected to the top of the first intermediate distillation column 112, and so on until the bottom liquid phase pipe 114 of the last intermediate distillation column 112 is connected to the top of the final distillation column 113. The top vapor phase pipe 115 of the final distillation column 113 is connected to the bottom of the last intermediate distillation column 112, and so on until the top vapor phase pipe of the first intermediate distillation column 112 is connected. 115 is connected to the bottom of the initial distillation column 111; the top vapor pipe 115 of the initial distillation column 111 is connected to the compressor 130, the compressor 130 is connected to the inlet of the heating medium channel of the reboiler 120, the outlet of the heating medium channel is connected to the separator 140, a reflux pump 141 is installed at the outlet of the separator 140, the outlet of the reflux pump 141 is connected to the reflux branch 150 and the top outlet branch 160 respectively, the reflux branch 150 is connected to the top of the initial distillation column 111; the bottom liquid pipe 114 of the terminal distillation column 113 is provided with a reboiler branch 170 and a bottom outlet branch 180, the reboiler branch 170 is connected to the material channel 121 of the reboiler 120, the material channel 121 and the heating medium channel exchange heat, and the outlet of the material channel 121 is connected to the bottom of the terminal distillation column 113.

[0047] According to the separation requirements of this embodiment, the number of separation stages is adjusted to 7, and the reflux ratio is adjusted to 355, with the raw material feed rate being 12.75 kg / h. 10 BF3 production rate 11 Please refer to Table 1 for BF3 production rate, heat load, and compression power consumption.

[0048] Examples 2-4 Examples 2-4 are basically the same as Example 1, except that the separation requirements are different, and the number of separation stages, reflux ratio, and feed tower 1121 are adjusted. Please refer to Table 1 for specific adjustment parameters. 10 BF3 production rate 11 Please refer to Table 1 for BF3 production rate, heat load, and compression power consumption.

[0049] Table 1. Statistical table of operating conditions and test results for different examples

[0050] In summary, the direct-refrigeration cryogenic distillation apparatus 100 for separating boron isotopes provided by this invention utilizes multi-stage distillation columns 110 to separate the isotopes of the raw material, constructing a continuous and stable concentration gradient. Simultaneously, the liquid phase material is discharged from the bottom of each distillation column 110 to the top of the next distillation column 110, while the gaseous phase material is discharged from the top of each distillation column 110 to the bottom of the previous distillation column 110, thereby achieving downward flow of the liquid phase and upward flow of the gas phase, forming counter-current convection. The gas and liquid phases are in full contact within the column, and the target isotope repeatedly transfers between the two phases, improving separation accuracy. Each distillation column 110 undertakes the separation task within a specific concentration range. The liquid phase carries heavy components (or target isotopes) to the lower-level column for further purification, while the gas phase carries light components to the upper-level column for enrichment. This gradually increases the concentration difference between the components and impurities, thereby achieving the gradual enrichment of the target components and ultimately separating boron isotopes. Simultaneously, this invention utilizes the heat released from the pressurized and heated gas phase at the top of the column to heat the reboiler 120, eliminating the need for additional heat sources and cooling sources. A large amount of cooling capacity is obtained with minimal electricity consumption, requiring only about 1 / 10 of the cooling capacity required for distillation. A significant amount of low-grade cooling capacity is recovered and reused through a circulating working fluid, maximizing energy efficiency and reducing equipment energy consumption. Compared to other chemical exchange distillation methods, this method eliminates the need for complexation and cracking processes, and subsequent impurity removal is also unnecessary, simplifying the process flow. Furthermore, high abundance is obtained at the top of the column during distillation separation. 11 BF3, high abundance at the base of the tower. 10 BF3.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An apparatus for the direct refrigeration cryogenic rectification separation of boron isotopes, characterized in that, It comprises a rectifying tower, a reboiler and a compressor, the rectifying tower comprises an initial rectifying tower, intermediate rectifying towers and a terminal rectifying tower which are connected in series, the number of intermediate rectifying towers is multiple and they are connected in series, one of the intermediate rectifying towers is selected as a feed tower, the rectifying towers are provided with a tower kettle liquid phase pipe and a tower top gas phase pipe, the reboiler comprises a material channel and a heating medium channel; The tower kettle liquid phase pipe of the initial rectifying tower is communicated with the tower top of the first intermediate rectifying tower, and so on until the tower kettle liquid phase pipe of the last intermediate rectifying tower is communicated with the tower top of the terminal rectifying tower; The tower top gas phase pipe of the terminal rectifying tower is communicated with the tower kettle of the last intermediate rectifying tower, and so on until the tower top gas phase pipe of the first intermediate rectifying tower is communicated with the tower kettle of the initial rectifying tower; The tower top gas phase pipe of the initial rectifying tower is communicated with the compressor, the compressor is communicated with the inlet of the heating medium channel of the reboiler, the outlet of the heating medium channel is provided with a reflux branch and a tower top extraction branch, the reflux branch is communicated with the tower top of the initial rectifying tower; The tower kettle liquid phase pipe of the terminal rectifying tower is provided with a reboiling branch and a tower kettle extraction branch, the reboiling branch is communicated with the material channel of the reboiler, the material channel and the heating medium channel are heat-exchanged, and the outlet of the material channel is communicated with the tower kettle of the terminal rectifying tower.

2. The apparatus for the direct refrigeration cryogenic rectification separation of boron isotopes according to claim 1, characterized in that, The device for directly refrigerating and low-temperature rectifying and separating boron isotopes further comprises a separator, the separator is communicated with the outlet of the heating medium channel, and the outlet of the separator is respectively communicated with the reflux branch and the tower top extraction branch.

3. The apparatus for the direct refrigeration cryogenic rectification separation of boron isotopes according to claim 2, characterized in that, A reflux pump is arranged at the outlet of the separator, and the outlet of the reflux pump is respectively communicated with the reflux branch and the tower top extraction branch.

4. The apparatus for the direct refrigeration cryogenic rectification separation of boron isotopes according to claim 1, characterized in that, A heat exchanger for maintaining the temperature of the device for directly refrigerating and low-temperature rectifying and separating boron isotopes is arranged on the reflux branch.

5. The apparatus for the direct refrigeration cryogenic rectification separation of boron isotopes according to claim 1, characterized in that, The device for directly refrigerating and low-temperature rectifying and separating boron isotopes is further provided with a feed pipe, a concentration detection module and a flow regulating valve are arranged on the feed pipe, the feed pipe is communicated with multiple intermediate rectifying towers through a multi-way valve, the concentration detection module is signal-connected with the multi-way valve to control the communication state of the multi-way valve, so as to adjust the feed position; And / or, the compressor is provided with a frequency regulation module for regulating the frequency of the compressor, and a purity detection mechanism is arranged on the tower kettle extraction branch, and the purity detection mechanism is signal-connected with the frequency regulation module.

6. A method of cryogenic rectification separation of boron isotopes by direct refrigeration, characterized in that, The device for directly refrigerating and low-temperature rectifying and separating boron isotopes is used in the device for directly refrigerating and low-temperature rectifying and separating boron isotopes according to any one of claims 1-5, and the device comprises: The raw material is fed into the feed tower, and after low-temperature rectification, liquid phase material and gas phase material are formed; The liquid phase material is transported to the tower top of the next intermediate rectifying tower through the tower kettle liquid phase pipe of the feed tower for low-temperature rectification, and so on until the tower kettle liquid phase of the last intermediate rectifying tower is transported to the tower top of the terminal rectifying tower, and the liquid phase material in the initial rectifying tower is transported to the tower top of the first intermediate rectifying tower, and so on until it is transported into the feed tower to form a cycle; The gas phase material is transported to the bottom of the last intermediate rectifying tower through the overhead gas phase pipe of the feed tower, and is subjected to low-temperature rectification, and so on until the liquid phase of the first intermediate rectifying tower is transported to the bottom of the initial rectifying tower; the gas phase material of the end rectifying tower is transported to the bottom of the last intermediate rectifying tower, and so on until it is transported into the feed tower to form a circulation; The liquid phase material of the end rectifying tower is divided into two paths, one of which is introduced into the material passage through the reboiler branch after being heated by the reboiler and then returned to the end rectifying tower, and the other of which is output as the tower bottom product through the tower bottom product branch; The gas phase material of the initial rectifying tower is compressed by the compressor, is heated and pressurized, and is transported to the heating medium passage of the reboiler as the heat source of the liquid phase material of the end rectifying tower input into the reboiler; the material output from the heating medium passage is divided into two paths, one of which is returned to the top of the initial rectifying tower through the reflux branch, and the other of which is output as the tower top product through the tower top product branch.

7. The method of claim 6, wherein the method is a direct refrigeration cryogenic rectification separation of boron isotopes. The material output from the heating medium passage is also subjected to gas-liquid separation through a separator, wherein the condensed liquid is divided into two paths.

8. The method of claim 6 wherein, The operating pressure of the initial rectifying tower, the intermediate rectifying tower and the end rectifying tower is controlled to be 101-150 kpaA, and the operating temperature is controlled to be -101--92℃.

9. The method of claim 6 wherein, The reflux ratio of the reflux branch and the tower top product branch is 150-2000.

10. The method of claim 6 wherein, The raw material includes natural abundance boron trifluoride or separated and enriched boron trifluoride. And / or, the feeding state of the raw material includes gas phase, liquid phase or gas-liquid mixture. And / or, the feeding state of the raw material includes gas phase, liquid phase or gas-liquid mixture.

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