A purification apparatus and method for medical-grade sulfur hexafluoride

Abstract

This invention provides a purification device and method for medical-grade sulfur hexafluoride. The purification device includes a shell and, within the shell, a MOF adsorption layer, an alumina adsorption layer, and a particle filter layer arranged sequentially from top to bottom; the height ratio of the MOF adsorption layer to the alumina adsorption layer is 1:(2.5-3.5). The purification method includes: passing sulfur hexafluoride raw material into the purification device, subjecting it to primary adsorption in the MOF adsorption layer, secondary adsorption in the alumina layer, and filtration in the particle filter layer, to obtain medical-grade sulfur hexafluoride. Using the purification device and method of this invention, impurity gases in industrial-grade sulfur hexafluoride can be effectively adsorbed to obtain high-purity medical-grade sulfur hexafluoride gas.

Description

Technical Field

[0001] This invention belongs to the field of separation and purification technology, and particularly relates to a purification device and method for medical-grade sulfur hexafluoride. Background Technology

[0002] Sulfur hexafluoride (SF6) is a colorless, non-toxic, and non-flammable inert gas, approximately five times denser than air. Currently, SF6 is primarily used in the power industry, serving as an arc-extinguishing agent in high-voltage switches and as insulation material in large-capacity transformers. The application of SF6 in the medical field has also seen significant development in recent years, particularly as an intraocular gas filling material in retinal detachment and vitrectomy surgeries. SF6 gas is chemically stable and can absorb nitrogen and oxygen from the air and blood, expanding to reposition the detached retina.

[0003] Unpurified industrial-grade sulfur hexafluoride gas contains impurities such as nitrogen, water, carbon dioxide, and methane, and may also contain sulfur fluoride (S₂F₂), sulfur tetrafluoride (SF₄), and disulfide decafluoride (S₂F₂). 10 ), sulfuryl fluoride (SO₂F₂), thionyl fluoride (SOF₂), decafluorodisulfide (S₂F₂) 10 The gas contains toxic impurities such as oxygen (O) and hydrogen fluoride (HF), which cannot meet the requirements for medical use.

[0004] Currently, the preparation of sulfur hexafluoride (SF6) generally involves the reaction of fluorine gas with sulfur. The crude SF6 gas produced is then continuously purified to obtain a product that meets industrial production requirements. CN103848402A discloses a method for preparing SF6, including the following steps: reacting fluorine gas with gaseous sulfur to generate crude SF6 gas; subjecting the crude SF6 gas to pyrolysis, washing, dehydration, deacidification, and distillation to obtain the SF6 product; testing the product; treating any SF6 products that fail the test until a qualified product is obtained; and recovering the tail gas separated during distillation. This method only removes S2F-containing gases. 10 and S2F 10 O contains toxic gases, hydrolyzable impurities, and acidic impurities.

[0005] However, the sulfur hexafluoride product obtained by the above purification methods cannot meet the requirements for medical grade. Therefore, providing a simple-to-operate purification device and method for medical-grade sulfur hexafluoride gas with high adsorption efficiency is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a purification device and method for medical-grade sulfur hexafluoride, which can effectively adsorb impurity gases in industrial-grade sulfur hexafluoride to obtain high-purity medical-grade sulfur hexafluoride gas.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a purification device for medical-grade sulfur hexafluoride, the purification device comprising a shell and, from top to bottom, an MOF adsorption layer, an alumina adsorption layer and a filter particle filter layer disposed within the shell.

[0009] The height ratio of the MOF adsorption layer to the alumina adsorption layer is 1:(2.5-3.5), for example, it can be 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3 or 1:3.4, etc., but is not limited to the values ​​listed. Other unlisted values ​​within this range are also applicable.

[0010] The purification device provided by this invention uses a multi-stage series adsorption method that differs from ordinary adsorbents. The MOF adsorption layer, alumina adsorption layer and filter particle filter layer are arranged sequentially from top to bottom. The purification is carried out by adsorption and impurity removal in a progressive manner, which can quickly adsorb fluorine and sulfur impurity compounds and impurity gases in sulfur hexafluoride gas, so that the product gas meets the medical-grade sterility standard.

[0011] It is worth noting that the purification device first passes through the MOF adsorption layer and then through the alumina adsorption layer, and the height ratio of the MOF adsorption layer and the alumina adsorption layer is controlled within a specific range, which helps to save costs and ensures the purification effect.

[0012] As a preferred technical solution of the present invention, the height of the MOF adsorption layer is 55-65mm, for example, it can be 56mm, 57mm, 58mm, 59mm, 60mm, 61mm, 62mm, 63mm or 64mm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] Preferably, the particle size of the MOF in the MOF adsorption layer is 100-800nm, for example, it can be 200nm, 300nm, 400nm, 500nm, 600nm or 700nm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] Preferably, the specific surface area of ​​the MOF in the MOF adsorption layer is 2000-5000 m². 2 / g, for example, could be 2500m 2 / g、3000m 2 / g、3500m 2 / g、4000m 2 / g or 4500m 2 / g, etc., but not limited to the listed values, other unlisted values ​​within this range also apply.

[0015] It is worth noting that this invention controls the particle size and specific surface area of ​​MOF materials within a specific range, which enables the rapid removal of impurity gases such as methane and carbon dioxide.

[0016] As a preferred embodiment of the present invention, the alumina adsorption layer is an active alumina adsorption layer.

[0017] Preferably, the height of the alumina adsorption layer is 170-190 mm, for example, it can be 172 mm, 174 mm, 175 mm, 176 mm, 178 mm, 180 mm, 182 mm, 184 mm, 186 mm or 188 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, the diameter of the active alumina in the alumina adsorption layer is 1-8 mm, for example, it can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm or 7 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the specific surface area of ​​the active alumina in the alumina adsorption layer is 280-360 m². 2 / g, for example, could be 290m 2 / g、300m 2 / g、310m 2 / g、320m 2 / g、330m 2 / g、340m 2 / g or 350m 2 / g, etc., but not limited to the listed values, other unlisted values ​​within this range also apply.

[0020] It is worth noting that the present invention controls the particle size and specific surface area of ​​activated alumina within a specific range, which can quickly remove impurity gases such as hydrofluoric acid, sulfur fluoride, sulfur tetrafluoride, decafluoride disulfide, sulfuryl fluoride, thionyl fluoride, and decafluoride disulfide.

[0021] As a preferred embodiment of the present invention, the filter particle filter layer comprises at least three filter membranes.

[0022] Preferably, the pore size of the filter membrane in the filter particle filter layer is 0.18-0.22 μm, for example, it can be 0.185 μm, 0.19 μm, 0.195 μm, 0.20 μm, 0.205 μm, 0.21 μm or 0.215 μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, the filter particle filter layer comprises a cellulose acetate filter membrane, a polytetrafluoroethylene filter membrane, and a polypropylene filter membrane stacked sequentially.

[0024] In this invention, the particulate filter layer in the purification device can effectively filter out particles, bacteria and other microorganisms present in the sulfur hexafluoride gas raw material.

[0025] In this invention, the filter particle filter layer is made of the above-mentioned three-layer membrane stack. The first layer is a cellulose acetate filter membrane, which is a hydrophilic filter membrane; the second layer is a hydrophobic polytetrafluoroethylene filter membrane, which can complement the hydrophilic cellulose acetate filter membrane; and the third layer is a polypropylene filter membrane, which can intercept larger particulate impurities, has a large dirt holding capacity, and has strong adsorption performance.

[0026] As a preferred embodiment of the present invention, the shell is made of stainless steel.

[0027] Preferably, the outer diameter of the housing is 55-65mm, for example, it can be 56mm, 57mm, 58mm, 59mm, 60mm, 61mm, 62mm, 63mm or 64mm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the surface roughness Ra of the inner wall of the housing is 0.25-0.5μm, for example, it can be 0.185μm, 0.19μm, 0.195μm, 0.20μm, 0.205μm, 0.21μm or 0.215μm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Secondly, the present invention provides a purification method for medical-grade sulfur hexafluoride, wherein the purification method is performed using the purification apparatus for medical-grade sulfur hexafluoride described in the first aspect.

[0030] The purification method provided by the present invention uses the purification device described in the first aspect, which can purify sulfur hexafluoride by adsorption filtration, and has low cost and excellent purification effect.

[0031] As a preferred technical solution of the present invention, the purification method includes: passing sulfur hexafluoride raw material into a purification device, and sequentially passing it through a MOF adsorption layer for primary adsorption, an alumina layer for secondary adsorption, and a filtration particle layer for filtration to obtain medical-grade sulfur hexafluoride.

[0032] As a preferred technical solution of the present invention, the temperature of the sulfur hexafluoride raw material during the purification process is 20-30℃, for example, it can be 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃ or 29℃, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] Preferably, the pressure of the sulfur hexafluoride raw material during purification is 0.58-0.62 MPa, for example, it can be 0.585 MPa, 0.59 MPa, 0.595 MPa, 0.60 MPa, 0.605 MPa, 0.61 MPa, 0.615 MPa or 0.62 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the flow rate of the sulfur hexafluoride feedstock during the purification process is 0.5-3 L / min, for example, it can be 0.7 L / min, 1 L / min, 1.5 L / min, 2 L / min or 2.5 L / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] This invention introduces sulfur hexafluoride raw material into the purification device at specific temperature, pressure and flow rate, ensuring that the output gas is high-purity medical-grade sulfur hexafluoride gas.

[0036] As a preferred technical solution of the present invention, the impurity content in the sulfur hexafluoride raw material is 10-1000ppm, for example, it can be 50ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm or 900ppm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 500-1000ppm.

[0037] Preferably, the impurities in the sulfur hexafluoride raw material include any one or a combination of at least two of the following: carbon monoxide, carbon dioxide, methane, water, carbon tetrafluoride, sulfur fluoride, sulfur tetrafluoride, decafluoride, sulfuryl fluoride, thionyl fluoride, decafluoride, or hydrogen fluoride. Typical but not limited combinations include: a combination of sulfur fluoride and sulfur tetrafluoride, a combination of decafluoride and sulfuryl fluoride, a combination of thionyl fluoride and decafluoride, and a combination of decafluoride and hydrogen fluoride.

[0038] Preferably, the purity of the medical-grade sulfur hexafluoride is ≥99.999%, for example, it can be 99.9991%, 99.9992%, 99.9993%, 99.9994%, 99.9995%, 99.9996%, 99.9997%, 99.9998%, or 99.9999%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 99.9995%.

[0039] The standard for pharmaceutical grade sulfur hexafluoride in this field is as follows: sulfur hexafluoride gas content not less than 99.999%, methane content not more than 0.1 ppm, carbon tetrafluoride content not more than 0.1 ppm, hydrogen fluoride content not more than 0.1 ppm, and the content of 0~0.3μm particles in the gas not more than 10 particles / m³. 3 The content of particles with a size of 0.3~10μm is no more than 3 particles / m³. 3 .

[0040] As a preferred technical solution of the present invention, the purification method includes: passing sulfur hexafluoride raw material with an impurity content of 10-1000ppm into a purification device, and subjecting it to primary adsorption in an MOF adsorption layer, secondary adsorption in an alumina layer, and filtration in a particle filter layer at a flow rate of 0.5-3L / min at 20-30℃ and 0.58-0.62MPa to obtain medical-grade sulfur hexafluoride with a purity ≥99.999%.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The purification device provided by the present invention has an MOF adsorption layer, an alumina adsorption layer and a filter particle filter layer arranged sequentially from top to bottom in the shell. It purifies the gas by adsorbing and removing impurities layer by layer, and can quickly adsorb fluorine and sulfur impurity compounds and other impurity gases in sulfur hexafluoride gas, so that the product gas meets the medical grade sterility standard.

[0044] (2) The purification device provided by the present invention adopts a multi-stage series adsorption method to purify sulfur hexafluoride gas, which overcomes the problems of poor separation effect, limited types of separated impurities, and low purity of other purification methods such as distillation, impurity conversion and membrane separation. At the same time, it has the advantage of being reusable and reduces costs.

[0045] (3) The purification method provided by this invention produces a product with high purity, meeting medical-grade standards. The content of all impurities is less than 0.01 ppm, and the content of 0-0.3 μm particles is less than 3 per m³. 3 . Attached Figure Description

[0046] Figure 1 A schematic diagram of a purification device for medical-grade sulfur hexafluoride provided in Example 1;

[0047] Wherein: 1-MOF adsorption layer, 2-alumina adsorption layer, 3-filter particle filter layer, 4-air inlet, 5-air outlet, 6-shell. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0049] It should be understood that in the description of this invention, terms such as "primary" and "secondary" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0050] Example 1

[0051] This embodiment provides a purification device for medical-grade sulfur hexafluoride, such as... Figure 1 As shown, the purification device includes a housing 6 and, within the housing 6, a MOF adsorption layer 1, an alumina adsorption layer 2, and a filter particle filter layer 3 arranged sequentially from top to bottom; the height ratio of the MOF adsorption layer 1 to the alumina adsorption layer 2 is 1:3.

[0052] The MOF adsorption layer 1 has a height of 60 mm, and the MOF material in the MOF adsorption layer 1 is ZIF-8, which has a particle size of 500 nm and a specific surface area of ​​3000 m². 2 / g;

[0053] The alumina adsorption layer 2 has a height of 180 mm, and the alumina adsorption layer 2 contains activated alumina with a particle size of 5 mm and a specific surface area of ​​320 m². 2 / g;

[0054] The filter particle filter layer 3 includes three filter membranes, namely a cellulose acetate filter membrane with a pore size of 0.22 μm, a polytetrafluoroethylene filter membrane with a pore size of 0.18 μm, and a polypropylene filter membrane with a pore size of 0.18 μm, which are stacked sequentially.

[0055] The housing 6 is made of stainless steel and has a cylindrical structure. The outer diameter of the housing 6 is 60 mm, and the surface roughness Ra of the inner wall of the housing 6 is 0.4 μm. An air inlet 4 is provided at the top of the housing 6, and an air outlet 5 is provided at the bottom of the housing 6.

[0056] Example 2

[0057] This embodiment provides a purification device for medical-grade sulfur hexafluoride. The purification device includes a shell and, from top to bottom, a MOF adsorption layer, an alumina adsorption layer, and a filter particle layer arranged sequentially within the shell. The height ratio of the MOF adsorption layer to the alumina adsorption layer is 1:2.5.

[0058] The MOF adsorption layer has a height of 60 mm, and the MOF material in the MOF adsorption layer is UIO-66, which has a particle size of 100 nm and a specific surface area of ​​4000 m². 2 / g;

[0059] The alumina adsorption layer has a height of 150 mm, and the alumina adsorption layer contains activated alumina with a particle size of 1 mm and a specific surface area of ​​350 m². 2 / g;

[0060] The filter particle filter layer includes three filter membranes, which are sequentially stacked as follows: a cellulose acetate filter membrane with a pore size of 0.20 μm, a polytetrafluoroethylene filter membrane with a pore size of 0.20 μm, and a polypropylene filter membrane with a pore size of 0.18 μm.

[0061] The housing is made of stainless steel and has a cylindrical structure. The outer diameter of the housing is 65 mm, the surface roughness Ra of the inner wall of the housing is 0.3 μm, the top of the housing is provided with an air inlet, and the bottom of the housing is provided with an air outlet.

[0062] Example 3

[0063] This embodiment provides a purification device for medical-grade sulfur hexafluoride. The purification device includes a shell and, from top to bottom, a MOF adsorption layer, an alumina adsorption layer, and a filter particle layer arranged sequentially within the shell. The height ratio of the MOF adsorption layer to the alumina adsorption layer is 1:3.5.

[0064] The MOF adsorption layer has a height of 60 mm, and the MOF material in the MOF adsorption layer is PCN with a particle size of 800 nm and a specific surface area of ​​2200 m². 2 / g;

[0065] The alumina adsorption layer has a height of 210 mm, and the alumina adsorption layer contains activated alumina with a particle size of 8 mm and a specific surface area of ​​290 m². 2 / g;

[0066] The filter particle filter layer comprises three filter membranes, which are sequentially stacked as follows: a cellulose acetate filter membrane with a pore size of 0.18 μm, a polytetrafluoroethylene filter membrane with a pore size of 0.20 μm, and a polypropylene filter membrane with a pore size of 0.22 μm.

[0067] The housing is made of stainless steel and has a cylindrical structure. The outer diameter of the housing is 55 mm, and the surface roughness Ra of the inner wall of the housing is 0.45 μm. An air inlet is provided at the top of the housing, and an air outlet is provided at the bottom of the housing.

[0068] Example 4

[0069] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the heights of the MOF adsorption layer and the alumina adsorption layer are 45 mm and 135 mm respectively, all other conditions are the same as in Embodiment 1.

[0070] Example 5

[0071] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the heights of the MOF adsorption layer and the alumina adsorption layer are 75 mm and 225 mm respectively, all other conditions are the same as in Embodiment 1.

[0072] Example 6

[0073] This embodiment provides a purification device for medical-grade sulfur hexafluoride, except that the ZIF-8 particles in the MOF adsorption layer have a particle size of 1000 nm and a specific surface area of ​​1500 m². 2 Except for / g, all other conditions were the same as in Example 1.

[0074] Example 7

[0075] This embodiment provides a purification device for medical-grade sulfur hexafluoride, except that the active alumina in the alumina adsorption layer has a particle size of 10 mm and a specific surface area of ​​200 m². 2 Except for / g, all other conditions were the same as in Example 1.

[0076] Example 8

[0077] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the filter particles filter layer consists of a polytetrafluoroethylene filter membrane with a pore size of 0.18 μm, a cellulose acetate filter membrane with a pore size of 0.22 μm, and a polypropylene filter membrane with a pore size of 0.18 μm stacked sequentially, all other conditions are the same as in Example 1.

[0078] Example 9

[0079] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the filter particle filter layer consists of a cellulose acetate filter membrane with a pore size of 0.12 μm, a polypropylene filter membrane with a pore size of 0.12 μm, and a polytetrafluoroethylene filter membrane with a pore size of 0.12 μm stacked in sequence, all other conditions are the same as in Example 1.

[0080] Example 10

[0081] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the filter particle filter layer does not contain a cellulose acetate filter membrane with a pore size of 0.22 μm, all other conditions are the same as in Example 1.

[0082] Example 11

[0083] This embodiment provides a purification device for medical-grade sulfur hexafluoride. Except that the filter particle filter layer does not contain a polytetrafluoroethylene filter membrane with a pore size of 0.18 μm, all other conditions are the same as in Example 1.

[0084] Comparative Example 1

[0085] This comparative example provides a purification device for medical-grade sulfur hexafluoride. Except that the purification device does not contain an MOF adsorption layer, all other conditions are the same as in Example 1.

[0086] Comparative Example 2

[0087] This comparative example provides a purification device for medical-grade sulfur hexafluoride. Except that the purification device does not contain an alumina adsorption layer, all other conditions are the same as in Example 1.

[0088] Comparative Example 3

[0089] This comparative example provides a purification device for medical-grade sulfur hexafluoride. Except for the alumina adsorption layer, MOF adsorption layer and filter particle filter layer arranged sequentially from top to bottom inside the shell, all other conditions are the same as in Example 1.

[0090] Comparative Example 4

[0091] This comparative example provides a purification device for medical-grade sulfur hexafluoride, except that the height of the alumina adsorption layer is 120 mm, and all other conditions are the same as in Example 1.

[0092] Comparative Example 5

[0093] This comparative example provides a purification device for medical-grade sulfur hexafluoride, except that the height of the alumina adsorption layer is 240 mm, and all other conditions are the same as in Example 1.

[0094] Application Example 1

[0095] This application example provides a purification method for medical-grade sulfur hexafluoride. The purification method uses the purification device provided in Example 1. The purification method includes: feeding the sulfur hexafluoride raw material into the purification device through the inlet, and sequentially passing it through the MOF adsorption layer for primary adsorption, the alumina layer for secondary adsorption, and the filter layer for filtration at a flow rate of 1 L / min at 25°C and 0.60 MPa, and then outputting it through the outlet to obtain medical-grade sulfur hexafluoride.

[0096] Application Example 2

[0097] This application example provides a purification method for medical-grade sulfur hexafluoride. The purification method uses the purification device provided in Example 2. The purification method includes: feeding the sulfur hexafluoride raw material into the purification device through the inlet, and sequentially passing it through the MOF adsorption layer for primary adsorption, the alumina layer for secondary adsorption, and the filter layer for filtration at a flow rate of 0.5 L / min at 20°C and 0.62 MPa, and then outputting it through the outlet to obtain medical-grade sulfur hexafluoride.

[0098] Application Example 3

[0099] This application example provides a purification method for medical-grade sulfur hexafluoride. The purification method uses the purification device provided in Example 3. The purification method includes: feeding the sulfur hexafluoride raw material into the purification device through the inlet, and sequentially passing it through the MOF adsorption layer for primary adsorption, the alumina layer for secondary adsorption, and the filter layer for filtration at a flow rate of 2.5 L / min at 30°C and 0.58 MPa, and then outputting it through the outlet to obtain medical-grade sulfur hexafluoride.

[0100] Application Example 4-11

[0101] Application Example 4-11 provides a purification method for medical-grade sulfur hexafluoride. Except for using the purification apparatus described in Examples 4-11, the other conditions are the same as in Application Example 1.

[0102] Compare and contrast examples 1-5

[0103] Comparative Application Examples 1-5 provide a purification method for medical-grade sulfur hexafluoride. Except for using the purification apparatus described in Comparative Examples 1-5, the other conditions are the same as in Application Example 1.

[0104] The impurity content of purified sulfur hexafluoride gas was analyzed by gas chromatography. The particle content in the purified sulfur hexafluoride gas was detected according to GB / T26570.1-2011 "Determination of Particle Content in Gases". The test results of the above application examples and comparative examples are shown in Table 1.

[0105] Table 1

[0106]

[0107] The following points can be drawn from Table 1:

[0108] (1) The purification apparatus provided in Examples 1-3 of the present invention has a sulfur hexafluoride purity ≥99.9995% and the impurity content also meets the medical grade standard;

[0109] (2) Based on the comprehensive application of Example 1 and the comparative application of Examples 4-5, it can be seen that if the height ratio of the MOF adsorption layer and the alumina adsorption layer is not set properly, it will lead to a decrease in the purity of sulfur hexafluoride gas and an increase in the impurity content.

[0110] (3) Combining Application Example 1 and Application Example 6, it can be seen that when the particle size of ZIF-8 material in the MOF adsorption layer is too large and the specific surface area is too low, it will lead to a decrease in the purity of sulfur hexafluoride gas and an increase in the impurity content; Combining Application Example 1 and Application Example 7, it can be seen that when the particle size of active alumina in the alumina adsorption layer is too large and the specific surface area is too low, it will lead to a decrease in the purity of sulfur hexafluoride gas and an increase in the impurity content.

[0111] (4) Based on the combined application examples 1 and 10-11, it can be seen that when the filter membrane of the filter layer is missing, it has little effect on the particle content in the sulfur hexafluoride gas, but has a significant impact on the purification life.

[0112] (5) Based on the comprehensive application of Example 1 and the comparative application of Example 1-2, it can be seen that if there is no MOF adsorption layer or alumina adsorption layer, the purity of sulfur hexafluoride gas will decrease and the impurity content will increase, which does not meet the medical grade sulfur hexafluoride standard.

[0113] (6) Based on the combined application example 1 and the comparative application example 3, it can be seen that if the order of the MOF adsorption layer and the alumina adsorption layer is changed, there is no significant effect on the purity of sulfur hexafluoride gas, but it has a negative impact on the service life of the purification device.

[0114] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A purification apparatus for medical grade sulfur hexafluoride, characterized by, The purification device comprises a shell and, sequentially from top to bottom in the shell, a MOF adsorption layer, an alumina adsorption layer and a filter particle filter layer. The height ratio of the MOF adsorption layer and the alumina adsorption layer is 1:2.5-3.

5.

2. The apparatus for purifying medical grade sulfur hexafluoride of claim 1, wherein, The height of the MOF adsorption layer is 55-65 mm.

3. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The particle size of the MOF in the MOF adsorption layer is 100-800 nm.

4. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The specific surface area of the MOF in the MOF adsorption layer is 2000-5000 m 2 / g.

5. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The height of the alumina adsorption layer is 170-190 mm.

6. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The diameter of the active alumina in the alumina adsorption layer is 1-8 mm.

7. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The specific surface area of the active alumina in the alumina adsorption layer is 280-360 m 2 / g.

8. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The filter particle filter layer comprises at least three filter membranes.

9. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The pore size of the filter membranes in the filter particle filter layer is 0.18-0.22 μm.

10. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The filter particle filter layer comprises, sequentially from top to bottom, an acetic acid fiber filter membrane, a polytetrafluoroethylene filter membrane and a polypropylene filter membrane.

11. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The shell is made of stainless steel.

12. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The outer diameter of the shell is 55-65 mm.

13. The medical grade sulfur hexafluoride purification apparatus of claim 1, wherein, The surface roughness Ra of the inner wall of the shell is 0.25-0.5 μm.

14. A method of purifying medical grade sulfur hexafluoride, characterized by, The purification method is performed using the medical sulfur hexafluoride purification device of any one of claims 1-13.

15. The method of purifying medical grade sulfur hexafluoride of claim 14, wherein, The purification method comprises: passing the sulfur hexafluoride raw material into the purification device, sequentially performing first-stage adsorption by the MOF adsorption layer, second-stage adsorption by the alumina layer and filtration by the filter particle filter layer, to obtain medical-grade sulfur hexafluoride.

16. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The temperature of the sulfur hexafluoride raw material during the purification process is 20-30℃.

17. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The pressure of the sulfur hexafluoride raw material during the purification process is 0.58-0.62 MPa.

18. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The flow rate of the sulfur hexafluoride raw material during the purification process is 0.5-3 L / min.

19. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The content of impurities in the sulfur hexafluoride raw material is 10-1000 ppm.

20. The method of purifying medical grade sulfur hexafluoride of claim 19, wherein, The content of impurities in the sulfur hexafluoride raw material is 500-1000 ppm.

21. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The impurities in the sulfur hexafluoride raw material include any one or a combination of at least two of carbon monoxide, carbon dioxide, methane, water, carbon tetrafluoride, sulfur fluoride, sulfur tetrafluoride, sulfur disulfide, sulfur oxyfluoride, sulfur thiofluoride, sulfur dioxyfluoride or hydrogen fluoride.

22. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The purity of the medical-grade sulfur hexafluoride is ≥99.999%.

23. The method of purifying medical grade sulfur hexafluoride of claim 22, wherein, The purity of the medical-grade sulfur hexafluoride is 99.9995%.

24. The method of purifying medical grade sulfur hexafluoride of claim 15, wherein, The purification method comprises: passing the sulfur hexafluoride raw material into the purification device, sequentially performing first-stage adsorption by the MOF adsorption layer, second-stage adsorption by the alumina layer and filtration by the filter particle filter layer at a temperature of 20-30℃, a pressure of 0.58-0.62 MPa and a flow rate of 0.5-3 L / min, to obtain medical-grade sulfur hexafluoride with a purity of ≥99.999%.

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