Method and device for removing carbon dioxide in boron trifluoride-11 and adsorbent regeneration method

Abstract

The invention belongs to the field of boron trifluoride purification, and discloses a method and device for removing carbon dioxide in boron trifluoride-11 and an adsorbent regeneration method.The removing method comprises the steps that 1, an absorbent is fed into an absorption device, and the adsorption device is filled with the adsorbent; (2) carrying out purging replacement and evacuation treatment on the device until the content of CO2 in the device is qualified; (3) introducing the boron trifluoride-11 raw material gas into an absorption device, absorbing carbon dioxide by an absorbent in the absorption device in a spraying manner, and after absorption, introducing the gas into an adsorption device filled with the absorbent to adsorb carbon dioxide; the absorbent is an imidazole tetrafluoroborate ionic liquid, an imidazole amino acid salt ionic liquid or a pyridine tetrafluoroborate ionic liquid; the adsorbent is prepared by using a 13X molecular sieve as a carrier and loading an ionic liquid by using an equivalent-volume impregnation method, the loading capacity of the ionic liquid is 10wt%-30wt%. The removal method is simple, the impurity removal efficiency is high, and the absorbent is regenerated in situ.

Description

Technical Field

[0001] The invention belongs to the field of boron trifluoride purification, and in particular relates to a method for removing carbon dioxide from boron trifluoride-11, a device thereof and an adsorbent regeneration method. Background Art

[0002] Boron trifluoride, as a boron reagent with high chemical reactivity, is widely used in boron fiber manufacturing and processing, organic boron compound preparation, organic synthesis catalyst, etc. Electronic grade boron trifluoride-11 is mainly used as a P-type doping source in silicon and germanium epitaxy, diffusion and ion implantation processes. It is an indispensable electronic special gas in the semiconductor industry. With the rapid development of the semiconductor industry, the demand for electronic special gases is also increasing. There are still technical barriers to the mass production of electronic grade boron trifluoride-11. Carbon dioxide is a key impurity in boron trifluoride-11 gas. How to effectively remove carbon dioxide from boron trifluoride-11 and reduce the distillation load is the focus of current research.

[0003] Whether it is physical absorption or chemical absorption, the absorption of carbon dioxide by absorption is subject to the limitations of the absorption equipment. The existence of dead zones in the equipment will lead to uneven mass transfer, and the carbon dioxide content after absorption is between 1.5 and 2.5 ppm, which limits its application. The adsorption method for removing carbon dioxide generally uses molecular sieve adsorbents to remove trace impurities, but the carbon dioxide content cannot be reduced to below 0.5 ppm. There are disadvantages such as poor removal effect, short adsorbent life, high regeneration and replacement frequency, adsorbent saturation within 3 to 4 days, need for regeneration operation, and difficulty in continuous operation. When using unmodified 13X molecular sieves for carbon dioxide adsorption, the adsorption effect is ultimately 1 to 2 ppm, which cannot meet the minimum standards required by national standards or enterprise standards. In addition, the traditional electric heating method has a long heating time, and there is uneven temperature distribution when heating the equipment, which will cause the regeneration effect of the absorbent and adsorbent at different positions inside the equipment to be too different, and the adsorption effect will deteriorate when used again, making it more difficult to achieve the desired adsorption effect. Electronic grade boron trifluoride-11 requires the final carbon dioxide content to be below 0.5 ppm. Therefore, it is necessary to develop new high-efficiency ionic liquid absorbents and molecular sieve adsorbents to remove carbon dioxide from boron trifluoride-11 and to improve the removal device and regeneration method. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a method for removing carbon dioxide from boron trifluoride-11, which can reduce the carbon dioxide content to below 0.5 ppm. The method is simple and has high impurity removal efficiency.

[0005] The second technical problem to be solved by the present invention is to provide a device for removing carbon dioxide from boron trifluoride-11, which can realize in-situ activation and regeneration of absorbent and adsorbent, and the time required for heating regeneration is short and the regeneration efficiency is high.

[0006] The third technical problem to be solved by the present invention is to provide a method for regenerating an absorbent and an adsorbent used in a method for removing carbon dioxide from boron trifluoride-11.

[0007] In order to solve the above-mentioned first technical problem, the technical solution of the present invention is a method for removing carbon dioxide from boron trifluoride-11, comprising the following steps: (1) The absorbent is sent into the absorption device, and the adsorbent is loaded into the adsorption device; (2) Use nitrogen to purge, replace and evacuate the device, repeating the operation until the carbon dioxide content in the device is less than 0.5ppm, the oxygen content is less than 0.5ppm, and the moisture content is less than 0.5ppm; (3) Boron trifluoride-11 raw gas is passed into an absorption device, and the absorbent absorbs carbon dioxide by spraying in the absorption device. After absorption, the gas enters an adsorption device filled with an adsorbent to adsorb carbon dioxide, thereby obtaining electronic grade boron trifluoride-11.

[0008] The absorbent is an imidazole tetrafluoroborate, an imidazole amino acid salt or a pyridine tetrafluoroborate ionic liquid synthesized from imidazole bromide, pyridine bromide, sodium amino acid and NaBF4. The imidazole bromide and pyridine bromide include one or more of 1-ethyl-3-methylimidazolium bromide ([Emim]Br), 1-butyl-3-methylimidazolium bromide ([Bmim]Br), 1-aminopropyl-3-butylimidazolium bromide ([NH2p-bim]Br), 1-aminopropyl-3-methylimidazolium bromide ([NH2p-mim]Br), N-butylpyridinium bromide ([BPy]Br), etc. The sodium amino acid includes one or more of sodium L-alaninate and sodium L-proline. The imidazole tetrafluoroborate, imidazole amino acid salt and pyridine tetrafluoroborate ionic liquids are 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-aminopropyl-3-butylimidazolium tetrafluoroborate ([NH2p-bim][BF4]), 1-aminopropyl-3-methylimidazolium tetrafluoroborate ([NH2p-mim][BF4]), 1-ethyl-3-methylimidazolium L-alaninate ([Emim][L-Ala]), 1-butyl-3-methylimidazolium L-alaninate ([Bmim][L-Ala]), 1-aminopropyl-3-butylimidazolium tetrafluoroborate ([NH2p-bim][BF4]), 1-aminopropyl-3-methylimidazolium tetrafluoroborate ([NH2p-mim][BF4]), -Butyl imidazole L-alaninate ([NH2p-bim][L-Ala]), 1-aminopropyl-3-methylimidazolium L-alaninate ([NH2p-mim][L-Ala]), 1-ethyl-3-methylimidazolium L-proline salt ([Emim][L-Pro]), 1-butyl-3-methylimidazolium L-proline salt ([Bmim][L-Pro]), 1-aminopropyl-3-butylimidazolium L-proline salt ([NH2p-bim][L-Pro]), 1-aminopropyl-3-methylimidazolium L-proline salt ([NH2p-mim][L-Pro]), N-butylpyridinium tetrafluoroborate ([BPy][BF4]).

[0009] The adsorbent is prepared by using 13X molecular sieve as a carrier, loading ionic liquid by equal volume impregnation method, and then drying and roasting. The ionic liquid is one or more of [Emim][BF4], [Bmim][BF4], [NH2p-bim][BF4], [NH2p-mim][BF4], [Emim][L-Ala], [Bmim][L-Ala], [NH2p-bim][L-Ala], [NH2p-mim][L-Ala], [Emim][L-Pro], [Bmim][L-Pro], [NH2p-bim][L-Pro], [NH2p-mim][L-Pro], [BPy][BF4], etc., wherein the loading amount of the ionic liquid is 10wt%~30wt%.

[0010] The 13X carrier particle size is preferably 2-5 mm.

[0011] Preferably, the carbon dioxide content in the boron trifluoride-11 feed gas is 30-50 ppm, the adsorption temperature is 20-50° C., and the adsorption pressure is 0.1-0.3 MPa.

[0012] Ionic liquids are used to pre-remove impurities from boron trifluoride-11, and modified molecular sieves are used to deeply remove carbon dioxide from boron trifluoride-11. Through absorption and adsorption, carbon dioxide in boron trifluoride-11 can be removed to below 0.5ppm, and the purity of boron trifluoride-11 reaches more than 99.995%. After subsequent distillation to remove light and heavy components, the purity of boron trifluoride-11 can reach more than 99.999%.

[0013] When boron trifluoride-11 is used for adsorption and impurity removal, the impurity removal efficiency is mainly affected by the pore size, adsorption temperature and pressure of different molecular sieve adsorbents. It is difficult to achieve the expected removal effect through a simple molecular sieve. The present invention modifies the molecular sieve through ionic liquid to increase the adsorption capacity of carbon dioxide by the molecular sieve. This is because the ionic liquid enhances the polarity of the molecular sieve surface and strengthens the interaction between the material and carbon dioxide. In addition, the ionic liquid itself has a certain absorption capacity for carbon dioxide. The molecular sieve adsorbent modified by imidazole and pyridine ionic liquids can provide more alkaline sites, thereby improving the adsorption capacity of the molecular sieve adsorbent.

[0014] To solve the above-mentioned second technical problem, the technical solution of the present invention is a device for removing carbon dioxide from boron trifluoride-11, comprising an absorption device 15 and an adsorption device 5, wherein the top of the absorption device 15 is connected to the bottom of the adsorption device 5; the outer walls of the absorption device 15 and the adsorption device 5 are both wrapped with an insulating layer 6, an electromagnetic induction coil 3 is wound around the insulating layer, and an insulating jacket 4 is arranged outside the electromagnetic induction coil; an absorbent delivery pump 13, an absorbent storage tank 12 and the absorption device 15 are connected to form a top-in and bottom-out loop, and an absorbent nozzle 16 is arranged in the absorption device 15; the bottoms of the absorption device 15 and the adsorption device 5 are both connected to a feed pipeline 10; the bottoms of the absorption device 15 and the adsorption device 5 are both connected to a vacuum pump 8.

[0015] Preferably, the thickness of the insulating layer is 1-2 mm.

[0016] Preferably, the electromagnetic induction heating frequency is 600-1200 kHz; the electromagnetic induction heating temperature is 100-550 °C.

[0017] The device of the present invention uses electromagnetic induction coils to perform electromagnetic induction heating on the metal shells of the absorption device and the adsorption device, and the absorption device and the adsorption device shells transfer heat to the ionic liquid and the adsorbent.

[0018] When the ionic liquid is saturated with absorption and the adsorbent is saturated with adsorption, the boron trifluoride-11 material in the absorption device and the adsorption device is emptied, and the ionic liquid and the adsorbent are activated and regenerated in situ by electromagnetic induction heating of the absorption device and the adsorption device, so as to realize the recycling of the ionic liquid and the adsorbent. The present invention provides a method for regenerating an absorbent and an adsorbent used in a method for removing carbon dioxide from boron trifluoride-11, comprising the following steps: (1) Empty the residual boron trifluoride-11 in the absorption device and the adsorption device, and purge and replace the absorption device and the adsorption device with nitrogen until the carbon dioxide content in the device is less than 0.5 ppm, the oxygen content is less than 0.5 ppm, and the moisture content is less than 0.5 ppm.

[0019] (2) The metal shells of the absorption device and the adsorption device are heated by induction heating, and the metal shells transfer heat to the ionic liquid absorbent and the molecular sieve adsorbent. The carbon dioxide absorbed by the ionic liquid and the carbon dioxide adsorbed in the molecular sieve adsorbent are taken away by nitrogen and high temperature, thereby achieving in-situ regeneration of the ionic liquid absorbent and the molecular sieve adsorbent.

[0020] The regeneration temperature of the absorbent and adsorbent is mainly controlled by the heating frequency. The heating frequency affects the heating rate. The higher the heating frequency, the faster the heating rate, and the molecular sieve adsorbent in the adsorption device is easier to reach the temperature required for regeneration in a short time. However, if the heating frequency is too high, the heat loss will increase and the thermal efficiency will decrease. In this application, the carrier of inductive heating is the material of the wall of the absorbent and adsorption device, not the filling in the device.

[0021] Compared with the prior art, the present invention has the following advantages: (1) The present invention changes the internal pore structure and specific surface area of ​​the adsorbent by using ionic liquid, and removes carbon dioxide by using a process combining ionic liquid and molecular sieve adsorbent modified by ionic liquid. The final carbon dioxide content is below 0.5 ppm. The method is simple, has high impurity removal efficiency, can quickly remove trace carbon dioxide, has a long adsorbent life, has high adsorption efficiency, and has a low regeneration frequency of the adsorbent, which is once every 12 to 15 days.

[0022] (2) The equipment described in the present invention has no dead zone, and the mass and heat transfer are uniform, and the regeneration effect of the absorbent and the adsorbent is uniform.

[0023] (3) Compared with ordinary electric heating methods, electromagnetic induction heating can achieve rapid heating of absorbents and adsorbents, with short heating time, high heat transfer efficiency, uniform heating temperature distribution, and can improve the regeneration efficiency of ionic liquids and adsorbents. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the adsorption regeneration device of the present invention.

[0025] Among them: 1-adsorption device venting pipeline; 2-flange head; 3-electromagnetic induction coil; 4-insulation jacket; 5-adsorption device; 6-insulation layer; 7-vacuum pipeline; 8-vacuum pump; 9-nitrogen pipeline; 10-feed pipeline; 11-absorbent return pipeline; 12-absorbent storage tank; 13-absorbent delivery pump; 14-absorbent liquid outlet pipeline; 15-absorption device; 16-absorbent nozzle; 17-absorption device venting pipeline; 18-absorption device discharge pipeline; 19-adsorption device discharge pipeline. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the background technology and technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings may only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] 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 present invention.

[0028] 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, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0029] In the embodiment of the present invention, gas chromatography is used to analyze the content of carbon dioxide in the adsorbed material. The gas chromatograph used is a GC9560 gas chromatograph, the chromatographic columns are CST column, 5A column and R column, and the detector is a PDD pulse discharge helium ionization detector; the determination method is an external standard method, the PDD detector temperature is 150°C, the column furnace temperature is 55°C, the carrier gas He pressure is 400 kPa, the driving gas pressure is 300 kPa, the sample gas pressure is 100 kPa, and the analysis time is 10 min.

[0030] like Figure 1 As shown, a device for removing carbon dioxide from boron trifluoride-11 includes an absorption device 15 and an adsorption device 5, wherein the top of the absorption device 15 is connected to the bottom of the adsorption device 5; the outer walls of the absorption device 15 and the adsorption device 5 are both wrapped with an insulating layer 6, an electromagnetic induction coil 3 is wound around the insulating layer, and a heat preservation jacket 4 is outside the electromagnetic induction coil; an absorbent delivery pump 13, an absorbent storage tank 12 and the absorption device 15 are connected to form a top-in and bottom-out loop, and an absorbent nozzle 16 is arranged in the absorption device 15; the bottoms of the absorption device 15 and the adsorption device 5 are both connected to a feed pipeline 10; the bottoms of the absorption device 15 and the adsorption device 5 are both connected to a vacuum pump 8. There is an ionic liquid in the absorption device, and there is a molecular sieve adsorbent modified by the ionic liquid in the adsorption device. The thickness of the insulating layer is 1~2mm. The electromagnetic induction heating frequency is 600~1200 kHz; and the electromagnetic induction heating temperature is 100~550 ℃.

[0031] Example 1

[0032] A method for removing carbon dioxide from boron trifluoride-11 comprises the following steps: (1) Preparation of absorbent, the absorbent is [Emim][BF4]. First, [Emim]Br and NaBF4 are used to synthesize ionic liquid [Emim][BF4] in a molar ratio of 1:1. After [Emim]Br and NaBF4 are reacted at 60°C for 8 hours, a turbid liquid is obtained. The NaBr is removed by vacuum filtration to obtain a clear solution of [Emim][BF4], that is, the [Emim][BF4] absorbent is obtained.

[0033] (2) Preparation of an adsorbent, which is a 13X molecular sieve loaded with [Emim][BF4], with a loading amount of 10 wt%. Using an equal volume impregnation method, 20.0 g of [Emim][BF4] was dissolved in 185 g of acetone, and then added dropwise to 200 g of 13X molecular sieve with a particle size of 2-3 mm using a dropper. After standing for 1 hour, the precursor was placed in a vacuum drying oven at 80°C for 5 hours, and then calcined in a muffle furnace at 350°C for 12 hours to obtain the adsorbent.

[0034] (3) After the preparation of the ionic liquid and molecular sieve adsorbents, they are loaded into the absorbent storage tank and the adsorption device respectively. After loading, the ionic liquid absorber and the adsorption device are purged and replaced. The absorber 15 and the adsorption device 5 are filled with nitrogen through the nitrogen pipeline 9. The absorber 15 and the adsorption device 5 are depressurized through the ionic liquid absorber vent pipeline 17 and the adsorption device vent pipeline 1. After the pressure is released to the normal pressure, the absorber 15 and the adsorption device 5 are evacuated through the vacuum pipeline 7 and the vacuum pump 8. The operation is continued until the replacement in the absorber 15 and the adsorption device 5 is qualified. Then, boron trifluoride-11 is introduced into the absorber 15 from the feed pipeline 10 at a gas flow rate of 0.3 L min -1 After being discharged from the absorption device discharge pipeline 18, the material enters the adsorption device 5. The gas pressure in the adsorption device is 0.3MPa. The gas is discharged from the adsorption device 5 through the adsorption device discharge pipeline 19. After ventilation for 1 hour, the carbon dioxide content is analyzed by gas chromatography. The chromatographic analysis results show that the carbon dioxide content is 0.23ppm.

[0035] (4) The saturated ionic liquid and molecular sieve catalyst are regenerated in situ in the absorption device and the adsorption device by induction heating, so as to realize the recycling of the ionic liquid and the adsorbent. During induction heating, the electromagnetic induction coil 3 in the insulation jacket 4 heats the absorption device 15 and the adsorption device 5. The induction heating frequency is 1000 kHz and the nitrogen purge flow rate is 1 L min. -1 , the ionic liquid regeneration temperature is 120℃, the adsorbent regeneration temperature is 300℃, and the regeneration time is 48h.

[0036] Example 2

[0037] The difference between this embodiment and embodiment 1 is that the loading amount of the adsorbent in step (2) is 20 wt%, and the required mass of [Emim][BF4] is 40.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.18 ppm.

[0038] Example 3

[0039] The difference between this embodiment and embodiment 1 is that the loading amount of the adsorbent in step (2) is 30 wt%, and the required mass of [Emim][BF4] is 60.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.15 ppm.

[0040] Example 4

[0041] The difference between this embodiment and embodiment 3 is that the pressure of the gas in the adsorption device in step (2) is 0.2 MPa. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.20 ppm.

[0042] Example 5

[0043] The difference between this embodiment and embodiment 3 is that the pressure of the gas in the adsorption device in step (2) is 0.1 MPa. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.25 ppm.

[0044] Example 6

[0045] Step (1) Preparation of [Bmim][BF4] absorbent. First, [Bmim]Br and NaBF4 are used to synthesize ionic liquid [Bmim][BF4] in a molar ratio of 1:1. After [Bmim]Br and NaBF4 are reacted at 80°C for 8 hours, a turbid liquid is obtained. After removing NaBr by vacuum filtration, a clear solution of [Bmim][BF4] is obtained, that is, the absorbent is obtained.

[0046] The difference between this embodiment and embodiment 3 is that in step (1), the absorbent is [Bmim][BF4], the adsorbent is 13X molecular sieve loaded with [Bmim][BF4], the loading amount is 30 wt%, and the required [Bmim][BF4] mass is 60.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.11 ppm.

[0047] Example 7

[0048] Step (1) Preparation of [BPy][BF4] absorbent. First, [BPy]Br and NaBF4 are used to synthesize ionic liquid [BPy][BF4] in a molar ratio of 1:1. After [BPy]Br and NaBF4 are reacted at 110°C for 8 hours, a turbid liquid is obtained. After removing NaBr by vacuum filtration, a clear solution of [BPy][BF4] is obtained, i.e., the absorbent is obtained.

[0049] The difference between this embodiment and embodiment 3 is that in step (1), the absorbent is [BPy][BF4], the adsorbent is 13X molecular sieve loaded with [BPy][BF4], the loading amount is 30 wt%, and the required mass of [BPy][BF4] is 60.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.12 ppm.

[0050] Example 8

[0051] Step (1) Preparation of [NH2p-bim][L-Ala] absorbent. First, [NH2p-bim]Br and sodium L-alanine are used to synthesize ionic liquid [NH2p-bim][L-Ala] in a molar ratio of 1:1. [NH2p-bim]Br and sodium L-alanine are reacted at 90°C for 8 hours to obtain a turbid liquid. After removing NaBr by vacuum filtration, a clear solution of [NH2p-bim][L-Ala] is obtained, thus preparing the absorbent.

[0052] The difference between this embodiment and embodiment 3 is that in step (1), the absorbent is [NH2p-bim][L-Ala], the adsorbent is 13X molecular sieve loaded with [NH2p-bim][L-Ala], the loading amount is 30 wt%, and the required mass of [NH2p-bim][L-Ala] is 60.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.09 ppm.

[0053] Example 9

[0054] Step (1) preparing [NH2p-mim][L-Pro] absorbent. First, [NH2p-mim]Br and sodium L-proline are used to synthesize ionic liquid [NH2p-mim][L-Pro] in a molar ratio of 1:1. [NH2p-mim]Br and sodium L-proline are reacted at 90°C for 8 hours to obtain a turbid liquid. After removing NaBr by vacuum filtration, a clear solution of [NH2p-mim][L-Pro] is obtained, thus preparing the absorbent. The difference between this embodiment and embodiment 3 is that in step (1), the absorbent is [NH2p-mim][L-Pro], the adsorbent is 13X molecular sieve loaded with [NH2p-mim][L-Pro], the loading amount is 30 wt%, and the required mass of [NH2p-mim][L-Pro] is 60.0 g. After ventilation for 1 hour, the carbon dioxide content was analyzed by gas chromatography, and the chromatographic analysis results showed that the carbon dioxide content was 0.10 ppm.

[0055] Comparative Example 1

[0056] The difference between this embodiment and embodiment 1 is that only the absorbent in step (1) is used to remove carbon dioxide, and no adsorption device and adsorbent are used for deep treatment. After ventilation for 1 hour, the carbon dioxide content is analyzed by gas chromatography, and the chromatographic analysis results show that the carbon dioxide content is 1.80 ppm.

[0057] Comparative Example 2

[0058] The difference between this embodiment and embodiment 1 is that only the adsorbent in step (2) is used to remove carbon dioxide, and the adsorbent is a 13X molecular sieve without ionic liquid. After ventilation for 1 hour, the carbon dioxide content is analyzed by gas chromatography, and the chromatographic analysis results show that the carbon dioxide content is 1.56 ppm.

[0059] Example 10

[0060] The difference between this embodiment and embodiment 1 is that after step (4), the adsorbent that has been regenerated in the adsorption device is re-evaluated, and the carbon dioxide content is analyzed by gas chromatography after ventilation for 1 hour. The chromatographic analysis results show that the carbon dioxide content is 0.24 ppm.

[0061] Embodiment 11

[0062] The difference between this embodiment and embodiment 1 is that in step (4), the induction heating frequency is 800 kHz, the required heating time is increased by 20 min, the adsorbent that has been regenerated in the adsorption device is re-evaluated, and the carbon dioxide content is analyzed by gas chromatography after ventilation for 1 hour. The chromatographic analysis results show that the carbon dioxide content is 0.27 ppm.

[0063] Example 12

[0064] The difference between this embodiment and embodiment 1 is that in step (4), the induction heating frequency is 1200 kHz, the required heating time is shortened by 10 min, the adsorbent that has been regenerated in the adsorption device is re-evaluated, and the carbon dioxide content is analyzed by gas chromatography after ventilation for 1 hour. The chromatographic analysis results show that the carbon dioxide content is 0.21 ppm.

[0065] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for removing carbon dioxide from boron trifluoride-11, comprising the following steps: (1) The absorbent is sent into the absorption device, and the adsorbent is loaded into the adsorption device; (2) Use nitrogen to purge, replace and evacuate the device, repeating the operation until the carbon dioxide content in the adsorption device is less than 0.5 ppm, the oxygen content is less than 0.5 ppm, and the moisture content is less than 0.5 ppm; (3) Boron trifluoride-11 raw gas is passed into an absorption device, and the absorbent absorbs carbon dioxide in the absorption device by spraying. After absorption, the gas enters an adsorption device filled with an adsorbent to adsorb carbon dioxide, thereby obtaining electronic grade boron trifluoride-11; The absorbent is an imidazole tetrafluoroborate, an imidazole amino acid salt or a pyridine tetrafluoroborate ionic liquid synthesized from imidazole bromide, pyridine bromide, sodium amino acid and NaBF4; the adsorbent is prepared by using 13X molecular sieve as a carrier, loading the ionic liquid by an equal volume impregnation method, and then drying and roasting; the loading amount of the ionic liquid is 10wt%~30wt%.

2. The method according to claim 1, characterized in that: The imidazole bromide and pyridine bromide refer to one or more of 1-ethyl-3-methylimidazolium bromide ([Emim]Br), 1-butyl-3-methylimidazolium bromide ([Bmim]Br), 1-aminopropyl-3-butylimidazolium bromide ([NH2p-bim]Br), 1-aminopropyl-3-methylimidazolium bromide ([NH2p-mim]Br), and N-butylpyridinium bromide ([BPy]Br); the amino acid sodium refers to one or more of L-alanine sodium and L-proline sodium.

3. The method according to claim 1, characterized in that The imidazole tetrafluoroborate, imidazole amino acid salt and pyridine tetrafluoroborate ionic liquids refer to 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-aminopropyl-3-butylimidazolium tetrafluoroborate ([NH2p-bim][BF4]), 1-aminopropyl-3-methylimidazolium tetrafluoroborate ([NH2p-mim][BF4]), 1-ethyl-3-methylimidazolium L-alaninate ([Emim][L-Ala]), 1-butyl-3-methylimidazolium L-alaninate ([Bmim][L-Ala]), 1-aminopropyl- 3-Butylimidazole L-alaninate ([NH2p-bim][L-Ala]), 1-aminopropyl-3-methylimidazole L-alaninate ([NH2p-mim][L-Ala]), 1-ethyl-3-methylimidazole L-proline salt ([Emim][L-Pro]), 1-butyl-3-methylimidazole L-proline salt ([Bmim][L-Pro]), 1-aminopropyl-3-butylimidazole L-proline salt ([NH2p-bim][L-Pro]), 1-aminopropyl-3-methylimidazole L-proline salt ([NH2p-mim][L-Pro]), N-butylpyridinium tetrafluoroborate ([BPy][BF4]).

4. The method according to claim 1, characterized in that The particle size of the 13X molecular sieve is 2-5 mm.

5. The method according to claim 1, characterized in that The carbon dioxide content in the boron trifluoride-11 raw gas is 30-50 ppm.

6. The method according to claim 1, characterized in that The adsorption temperature is 20~50 ℃, and the adsorption pressure is 0.1~0.3 MPa.

7. A device for removing carbon dioxide from boron trifluoride-11, comprising an absorption device (15) and an adsorption device (5), wherein the top of the absorption device (15) is connected to the bottom of the adsorption device (5); the outer walls of the absorption device (15) and the adsorption device (5) are both wrapped with an insulating layer (6), an electromagnetic induction coil (3) is wound outside the insulating layer, and an insulating jacket (4) is outside the electromagnetic induction coil; an absorbent delivery pump (13), an absorbent storage tank (12) and the absorption device (15) are connected to form a top-in and bottom-out loop, and an absorbent nozzle (16) is arranged in the absorption device (15); the bottoms of the absorption device (15) and the adsorption device (5) are both connected to a feed pipeline (10); and the bottoms of the absorption device (15) and the adsorption device (5) are both connected to a vacuum pump (8).

8. The device according to claim 7, characterized in that The thickness of the insulation layer is 1~2 mm.

9. The device according to claim 7, characterized in that The electromagnetic induction heating frequency is 600~1200 kHz; the electromagnetic induction heating temperature is 100~550 ℃.

10. A method for regenerating an absorbent and an adsorbent used in a method for removing carbon dioxide from boron trifluoride-11, comprising the following steps: (1) Empty the residual boron trifluoride-11 in the absorption device and the adsorption device, and purge and replace the absorption device and the adsorption device with nitrogen until the carbon dioxide content in the device is less than 0.5 ppm, the oxygen content is less than 0.5 ppm, and the moisture content is less than 0.5 ppm; (2) The metal shells of the absorption device and the adsorption device are heated by induction heating, and the metal shells transfer heat to the ionic liquid absorbent and the molecular sieve adsorbent. The carbon dioxide absorbed by the ionic liquid and the carbon dioxide adsorbed in the molecular sieve adsorbent are taken away by nitrogen and high temperature, thereby achieving in-situ regeneration of the ionic liquid absorbent and the molecular sieve adsorbent.

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