Method for preparing electronic grade carbon dioxide and device for preparing electronic grade carbon dioxide

Abstract

The present invention relates to the field of gas purification and discloses a method for preparing electronic-grade carbon dioxide and an apparatus for preparing electronic-grade carbon dioxide. The preparation method comprises: compressing the gas phase obtained by gas-liquid separation of epoxy decarbonization regeneration gas, then dehydrogenating the obtained compressed gas, and then drying, liquefying, and purifying the dehydrogenated gas to obtain the electronic-grade carbon dioxide; wherein, the total hydrocarbon content in the epoxy decarbonization regeneration gas is less than or equal to 0.7 Vol%, and the content of epoxy alkanes is less than or equal to 10 ppm; the dehydrogenation method comprises: contacting the pressurized gas with modified activated carbon. Using epoxy decarbonization regeneration gas as raw gas, the method is used to prepare electronic-grade carbon dioxide, avoiding the use of catalytic oxidation for dehydrogenation. While obtaining high-quality electronic-grade carbon dioxide, energy consumption is also greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of gas purification, and in particular to a method for preparing electronic-grade carbon dioxide and a device for preparing electronic-grade carbon dioxide. Background Art

[0002] With the development of electronics industries such as integrated circuits, optical fibers, and semiconductors, the application of electronic-grade carbon dioxide is becoming increasingly widespread. It is commonly used in oxidation, diffusion, chemical vapor deposition, and supercritical cleaning. Currently, the main carbon dioxide products on the market are industrial and food-grade, with purities ranging from 99.0% to 99.9%. Electronic-grade carbon dioxide has a higher purity, reaching above 99.999%.

[0003] The process for producing carbon dioxide typically involves pressurization, drying, dehydration, and liquefaction. If the feed gas contains a high hydrocarbon content, a catalytic oxidation stage is added after pressurization to remove the hydrocarbons. The catalytic oxidation stage operates at a reaction temperature of 300-450°C and requires the introduction of oxygen, which consumes significant energy. Furthermore, the refrigerants used in the liquefaction stage's freezers are ammonia and chlorine-containing refrigerants, which are both hazardous and environmentally harmful.

[0004] CN109336113A discloses a method for producing ultrapure carbon dioxide. The process involves vaporizing liquid carbon dioxide, heating, desulfurizing, catalytic conversion, adsorption drying, refrigeration, and purification. This process can produce 99.9995% electronic-grade ultrapure carbon dioxide. The catalytic conversion stage operates at a temperature of 300-500°C, resulting in high energy consumption.

[0005] CN109721054A discloses a production method and apparatus, including a dehydrogenation unit, a dehydration unit, a liquefaction unit, and a purification unit. The dehydrogenation unit utilizes a catalytic oxidation process, while the liquefaction unit uses liquid ammonia as a refrigerant. This leads to issues such as high energy consumption and the dangers of liquid ammonia.

[0006] Therefore, there is an urgent need for a process for preparing electronic-grade carbon dioxide that avoids the use of a high-energy catalytic oxidation method for dehydrogenation when using a raw gas with a high hydrocarbon content to prepare electronic-grade carbon dioxide. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problem in the prior art that when using raw gas with a high hydrocarbon content to prepare electronic-grade carbon dioxide, a catalytic oxidation method with high energy consumption is required for dehydrogenation. A method for preparing electronic-grade carbon dioxide and an apparatus for preparing electronic-grade carbon dioxide are provided. The preparation method uses epoxy decarbonization regeneration gas as raw gas and modified activated carbon as an adsorbent for dehydrogenation, avoiding the use of catalytic oxidation for dehydrogenation. While obtaining high-quality electronic-grade carbon dioxide, energy consumption is greatly reduced.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing electronic-grade carbon dioxide, wherein the preparation method comprises: compressing the gas phase obtained by gas-liquid separation of epoxy decarburization regeneration gas, then dehydrogenating the obtained compressed gas, and then drying, liquefying and purifying the obtained dehydrogenated gas to obtain the electronic-grade carbon dioxide; wherein,

[0009] The content of total hydrocarbons in the epoxy decarbonization regeneration gas is less than or equal to 0.7 Vol%, and the content of epoxy alkylene is less than or equal to 10 ppm. The dehydrogenation method includes: contacting the compressed gas with modified activated carbon.

[0010] A second aspect of the present invention provides an apparatus for preparing electronic-grade carbon dioxide, wherein the apparatus comprises: a coalescing separator, a compressor, an adsorption tower, a drying tower, a refrigerator, and a distillation tower connected in sequence;

[0011] The coalescing separator is used to separate the epoxy decarbonization regeneration gas into gas and liquid; the compressor is used to compress the gas phase obtained by the gas-liquid separation; the adsorption tower is used to dehydrogenate the compressed gas; the drying tower is used to dry the dehydrogenated gas obtained by the dehydrogenation; the refrigerator is used to liquefy the dried gas; and the distillation tower is used to purify the liquefied product to obtain electronic grade carbon dioxide.

[0012] Through the above technical solution, the beneficial effects of the present invention are:

[0013] The present invention provides a method for producing electronic-grade carbon dioxide, comprising subjecting epoxy decarbonization regeneration gas to gas-liquid separation, compression, dehydrogenation, drying, liquefaction, and purification. The dehydrogenation is performed using modified activated carbon as an adsorbent. Using epoxy decarbonization regeneration gas with a total hydrocarbon content of less than or equal to 0.7% by volume and an alkylene oxide content of less than or equal to 10 ppm as feed gas, this method produces electronic-grade carbon dioxide, avoiding the need for catalytic oxidation for dehydrogenation. While producing high-quality electronic-grade carbon dioxide, it also significantly reduces energy consumption.

[0014] In a preferred embodiment of the present invention, by selecting suitable modified activated carbon, including selecting suitable specific surface area, average particle size, average pore size and porosity of the activated carbon, and suitable type, average particle size and content of loaded metal particles, the modified activated carbon has a good dehydrogenation effect for epoxy decarbonization regeneration gas with a total hydrocarbon content of less than or equal to 0.7 Vol% and an alkylene oxide content of less than or equal to 10 ppm. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart for preparing electronic-grade carbon dioxide in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0016] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0017] The first aspect of the present invention provides a method for preparing electronic-grade carbon dioxide, wherein the preparation method comprises: compressing the gas phase obtained by gas-liquid separation of epoxy decarburization regeneration gas, then dehydrogenating the obtained compressed gas, and then drying, liquefying and purifying the obtained dehydrogenated gas to obtain the electronic-grade carbon dioxide; wherein,

[0018] The content of total hydrocarbons in the epoxy decarbonization regeneration gas is less than or equal to 0.7 Vol%, and the content of epoxy alkylene is less than or equal to 10 ppm. The dehydrogenation method includes: contacting the compressed gas with modified activated carbon.

[0019] The regeneration gas of the decarbonization unit of the epoxy device mainly contains carbon dioxide, and also contains trace amounts of hydrocarbon gases such as methane, ethylene, ethylene oxide, and gases such as hydrogen and oxygen. This part of the gas needs to be removed to meet the requirements of electronic-grade carbon dioxide; in addition, impurities such as moisture in the raw gas must also be removed to meet product requirements. The preparation method of electronic-grade carbon dioxide provided by the present invention includes gas-liquid separation, compression, dehydrogenation, drying, liquefaction and purification of the epoxy decarbonization regeneration gas; wherein, modified activated carbon is used as an adsorbent for dehydrogenation. The epoxy decarbonization regeneration gas with a total hydrocarbon content of less than or equal to 0.7 Vol% and an alkylene oxide content of less than or equal to 10 ppm is used as the raw gas, and the method is used to prepare electronic-grade carbon dioxide, thereby avoiding the use of catalytic oxidation for dehydrogenation. While obtaining high-quality electronic-grade carbon dioxide, it also greatly reduces energy consumption.

[0020] According to the present invention, preferably, the modified activated carbon comprises activated carbon and metal particles supported in the pores of the activated carbon.

[0021] According to the present invention, preferably, the metal particles are selected from copper particles and / or magnesium particles, preferably copper particles and magnesium particles. Using activated carbon loaded with copper particles and magnesium particles as an adsorbent can effectively adsorb hydrocarbon gases.

[0022] According to the present invention, preferably, the specific surface area of ​​the activated carbon is 1000-3000m 2 / g, preferably 1800-2500m 2 / g; the average particle size is 1-5mm, preferably 2-4mm.

[0023] According to the present invention, preferably, the activated carbon has an average pore diameter of 3-30 nm, preferably 25-30 nm; a porosity of 0.7-0.9 cm 3 / g, preferably 0.8-0.9cm 3 / g.

[0024] According to the present invention, preferably, in the modified activated carbon, the average particle size of the copper particles is 3-10 nm, and the average particle size of the magnesium particles is 5-20 nm.

[0025] Modified activated carbon made from activated carbon, copper particles and magnesium particles that meet the above conditions can effectively adsorb hydrocarbon gases.

[0026] According to the present invention, preferably, the copper particles and magnesium particles in the modified activated carbon comprise 0.8-1.5 wt% and 0.3-0.9 wt%, respectively, based on the total weight of the modified activated carbon. The copper and magnesium particles in the modified activated carbon within these ranges effectively adsorb total hydrocarbons in the feed gas, otherwise, adsorption of total hydrocarbons may be insufficient.

[0027] In order to achieve better results in dehydrogenation, drying, liquefaction and purification, the gas obtained by gas-liquid separation of epoxy decarbonization regeneration gas is compressed before dehydrogenation. According to the present invention, preferably, the compression method includes: pressurizing the gas phase obtained by gas-liquid separation to 2.3-3 MPa.

[0028] According to the present invention, preferably, in the dehydrogenation process, based on the total volume of the epoxy decarbonization regeneration gas being 1 L, the amount of the modified activated carbon used is 30-60 g.

[0029] According to the present invention, preferably, the dehydrogenation process comprises: contacting the compressed gas with the modified activated carbon at 35-45° C. for 10-30 minutes.

[0030] According to the present invention, preferably, the content of total hydrocarbons in the dehydrocarbonized gas is less than or equal to 2 ppm.

[0031] According to the present invention, preferably, the drying method comprises: contacting the dehydrocarbonized gas with a molecular sieve.

[0032] According to the present invention, preferably, the molecular sieve has pores with an average pore diameter of 0.3-0.5 nm; for example, it can be selected from at least one of 3A molecular sieve, 4A molecular sieve and 5A molecular sieve.

[0033] According to the present invention, preferably, based on the total volume of the epoxy decarbonization regeneration gas being 1 L, the amount of the molecular sieve used is 30-60 g.

[0034] According to the present invention, preferably, the drying conditions include: contacting the dehydrocarbon gas with the molecular sieve at 20-40° C. for 10-30 minutes.

[0035] According to the present invention, preferably, the water content in the dry gas obtained by drying is below 3 ppm.

[0036] In the present invention, ppm is based on volume.

[0037] According to the present invention, preferably, the liquefaction conditions include: the refrigerant is carbon dioxide, and the refrigeration temperature is -25°C to -10°C. Compared with conventional ammonia refrigerants and fluorine-containing refrigerants, using carbon dioxide as the refrigerant has better refrigeration effect and a safer preparation process.

[0038] According to the present invention, preferably, the purification method comprises: subjecting the liquefied product obtained by the liquefaction to distillation.

[0039] According to the present invention, preferably, the distillation conditions include: temperature of -22°C to -15°C, and pressure of 1.5-2.1 MPa.

[0040] A second aspect of the present invention provides an apparatus for preparing electronic-grade carbon dioxide, wherein the apparatus comprises: a coalescing separator, a compressor, an adsorption tower, a drying tower, a refrigerator, and a distillation tower connected in sequence;

[0041] The coalescing separator is used to separate the epoxy decarbonization regeneration gas into gas and liquid; the compressor is used to compress the gas phase obtained by the gas-liquid separation; the adsorption tower is used to dehydrogenate the compressed gas; the drying tower is used to dry the dehydrogenated gas obtained by the dehydrogenation; the refrigerator is used to liquefy the dried gas; and the distillation tower is used to purify the liquefied product to obtain electronic grade carbon dioxide.

[0042] According to the present invention, preferably, the adsorption tower is filled with modified activated carbon.

[0043] According to the present invention, preferably, the drying tower is filled with molecular sieves.

[0044] In the device for preparing electronic-grade carbon dioxide in the second aspect of the present invention, the modified activated carbon and molecular sieve are exactly the same as those in the method for preparing electronic-grade carbon dioxide described in the first aspect of the present invention. In order to avoid repetition, the present invention will not be further described in this second aspect, and those skilled in the art should not understand it as a limitation of the present invention.

[0045] According to the present invention, preferably, the device includes two sets of adsorption towers and two sets of drying towers. The two adsorption towers are provided, with one set performing adsorption while the modified activated carbon in the other set undergoes regeneration and cold blowing after use. The two sets of adsorption towers are used alternately, with nitrogen being the regeneration and cold blowing medium. Two drying towers are provided, with one drying tower performing drying while the molecular sieve in the other undergoes regeneration and cold blowing after use. The two towers are operated alternately, with air being the regeneration and cold blowing medium.

[0046] According to the present invention, preferably, the filtration accuracy of the filter element in the coalescing separator is 0.1-1 μm.

[0047] According to the present invention, preferably, the distillation tower is connected to the adsorption tower and the drying tower respectively, and the gas phase flowing out of the distillation tower is mixed with the dehydrocarbonized gas flowing out of the adsorption tower and then enters the drying tower, so that the gas phase flowing out of the top of the distillation tower is heat exchanged with the dehydrocarbonized gas entering the drying tower, thereby reducing the moisture entering the drying tower.

[0048] According to a preferred embodiment of the present invention, Figure 1 The method for preparing electronic grade carbon dioxide in the device provided by the present invention is described, comprising the following steps:

[0049] The epoxy decarbonization regeneration gas first passes through a coalescing separator for gas-liquid separation to remove tiny impurities contained therein, and then the gas phase flowing out of the coalescing separator enters a compressor for pressurization to 2.3-3MPa. The obtained compressed gas is cooled to 35-45°C and then enters an adsorption tower (two groups of adsorption towers are set up, one group of adsorption towers is used for adsorption, and the modified activated carbon in the other group of adsorption towers is regenerated and cold-blown after use. The two groups of adsorption towers are used alternately, and nitrogen is used as the regeneration and cold-blowing medium), with a residence time of 10-30 minutes; the adsorption tower is filled with modified activated carbon (based on the total volume of the epoxy decarbonization regeneration gas being 1L, the amount of the modified activated carbon is 30-60g), and the hydrocarbon substances contained therein are removed to less than or equal to 2ppm. The obtained dehydrocarbon gas then enters the dehydration and drying section, and is dehydrated in a drying tower (two drying towers are set up, one drying tower is used for drying, and the molecular sieve in the other drying tower is regenerated and cold-blown after use. The two towers are operated alternately, and the regeneration and cold-blowing medium is air) at 20-40 ° C for dehydration, with a residence time of 10-30 min; the drying tower is filled with molecular sieves (based on the total volume of the epoxy decarbonization regeneration gas being 1L, the amount of the molecular sieve is 30-60g) to reduce the water content to below 3ppm. The drying gas enters a carbon dioxide refrigerator and is liquefied at a refrigeration temperature of -25 ° C to -10 ° C. The liquefied product is introduced into a distillation tower and purified at a temperature of -22 ° C to -15 ° C and a pressure of 1.5-2.1 MPa. The liquid coming out of the bottom of the distillation tower is an electronic-grade carbon dioxide product. The gas phase flowing out of the top of the distillation tower exchanges heat with the dehydrocarbon gas entering the drying tower.

[0050] The present invention will be described in detail below through examples and comparative examples. In the following examples and comparative examples, unless otherwise specified, all methods are conventional; and all reagents and materials used, unless otherwise specified, can be obtained from commercial sources.

[0051] The composition and purity of the carbon dioxide product are determined in accordance with the determination method in GB / T23938-2021 High-purity Carbon Dioxide.

[0052] The following examples are used to illustrate the preparation of electronic grade carbon dioxide

[0053] Examples 1-8

[0054] The composition of the epoxy decarburization regeneration gas in Examples 1-8 is shown in Table 1.

[0055] Follow these steps to prepare electronic grade carbon dioxide:

[0056] The epoxy decarbonization regeneration gas first passes through a coalescing separator for gas-liquid separation (the filtration accuracy of the filter element is 1μm) to separate the tiny impurities contained therein. Then the gas phase flowing out of the coalescing separator enters the compressor for pressurization to 2.8MPa. The compressed gas obtained is cooled to 40°C and then enters the adsorption tower (two groups of adsorption towers are set up, one group of adsorption towers is used for adsorption, and the modified activated carbon in the other group of adsorption towers is regenerated and cold-blown after use. The two groups of adsorption towers are used alternately, and nitrogen is used as the regeneration and cold-blowing medium). The residence time is 30min; the adsorption tower is filled with modified activated carbon (based on the total volume of epoxy decarbonization regeneration gas being 1L, the amount of modified activated carbon is 60g) to remove the hydrocarbon substances contained therein to 2ppm. The dehydrocarbonized gas then enters the dehydration and drying section and is dehydrated in a drying tower at a temperature of 35°C (two drying towers are set up, one drying tower is used for drying, and the molecular sieve in the other drying tower is regenerated and cold-blown after use. The two towers are operated alternately, and air is used as the regeneration and cold-blowing medium).

[0057] The residence time is 30 minutes. The drying tower is filled with 3A molecular sieve (50g per 1L of epoxy decarbonization regeneration gas) to reduce the water content to below 3ppm. The drying gas enters a CO2 refrigerator for liquefaction at a refrigeration temperature of -25°C. The liquefied product is introduced into a distillation tower for purification at a pressure of 1.9 MPa and a temperature of -15°C. The liquid exiting the distillation tower is the electronic-grade CO2 product. The gaseous phase flowing out of the distillation tower exchanges heat with the dehydrogenated gas entering the drying tower.

[0058] The modified activated carbon is activated carbon loaded with copper particles and magnesium particles; based on the total weight of the modified activated carbon, the contents of the copper particles and the magnesium particles in the modified activated carbon are 1 wt% and 0.7 wt%, respectively;

[0059] The specific surface area of ​​activated carbon is 2000m 2 / g, average particle size is 3mm, average pore size is 30nm, and porosity is 0.8cm 3 / g; the average particle size of the copper particles is 6nm, and the average particle size of the magnesium particles is 15nm.

[0060] Example 9

[0061] Electronic grade carbon dioxide was prepared according to the method of Example 1, except that the specific surface area and average particle size of the modified activated carbon were different. The specific surface area of ​​the activated carbon was 1500 m 2 / g, with an average particle size of 5mm. Electronic grade carbon dioxide product was obtained.

[0062] Example 10

[0063] Electronic grade carbon dioxide was prepared according to the method of Example 1, except that the average pore size and porosity of the modified activated carbon were different. The average pore size of the activated carbon was 20 nm and the porosity was 0.7 cm 3 / g. Electronic grade carbon dioxide product is obtained.

[0064] Example 11

[0065] Electronic-grade carbon dioxide was prepared according to the method of Example 1, except that the modified activated carbon was loaded with iron particles. Specifically, the modified activated carbon was loaded with copper, magnesium, and iron particles; the average particle size of the iron particles was 30 nm; and the copper, magnesium, and iron particles were present in an amount of 1 wt%, 0.7 wt%, and 0.3 wt%, respectively, based on the total weight of the modified activated carbon. This resulted in an electronic-grade carbon dioxide product.

[0066] Example 12

[0067] Electronic-grade carbon dioxide was prepared according to the method of Example 1, except that the modified activated carbon was loaded with only copper particles. Specifically, the modified activated carbon was loaded with copper particles; the copper content in the modified activated carbon was 1.7 wt % based on the total weight of the modified activated carbon. This resulted in an electronic-grade carbon dioxide product.

[0068] Example 13

[0069] Electronic-grade carbon dioxide was prepared according to the method of Example 1, except that the modified activated carbon was different and copper particles of equal weight and average particle size were replaced with iron particles, thereby obtaining an electronic-grade carbon dioxide product.

[0070] Example 14

[0071] Electronic-grade carbon dioxide was prepared according to the method of Example 1, except that the contents of copper and magnesium particles in the modified activated carbon were varied. Specifically, the contents of copper and magnesium particles were 0.5 wt% and 0.2 wt%, respectively, based on the total weight of the modified activated carbon. This resulted in an electronic-grade carbon dioxide product.

[0072] Example 15

[0073] Electronic-grade carbon dioxide was prepared according to the method of Example 1, except that the average particle sizes of the copper particles and the magnesium particles in the modified activated carbon were different: the average particle size of the copper particles was 12 nm, and the average particle size of the magnesium particles was 26 nm. Thus, an electronic-grade carbon dioxide product was obtained.

[0074] Comparative Example 1

[0075] The carbon dioxide product was prepared according to the method of Example 1, except that a carbon dioxide having a specific surface area of ​​2000 m 2 / g, average particle size is 3mm, average pore size is 30nm, and porosity is 0.8cm 3 / g of activated carbon can replace the same weight of modified activated carbon to obtain carbon dioxide product.

[0076] Comparative Example 2

[0077] The carbon dioxide product was prepared according to the method of Example 1, except that the composition of the epoxy decarburization regeneration gas was different. The composition of the epoxy decarburization regeneration gas is shown in Table 1. A carbon dioxide product was obtained.

[0078] Test Case

[0079] The composition of the epoxy decarburization regeneration gas used in each embodiment and comparative example and the composition and purity parameters of the obtained carbon dioxide product are shown in Table 1.

[0080] Table 1

[0081]

[0082] The results in Table 1 show that the carbon dioxide products prepared using the method of the present invention in Examples 1-15 all meet the standards for electronic-grade carbon dioxide. Comparative Example 1, however, uses activated carbon without metal particles in its pores for dehydrogenation, and Comparative Example 2 uses epoxy decarbonization regeneration gas feedstock with excessive total hydrocarbon and alkylene oxide contents. Although the carbon dioxide purity of the obtained carbon dioxide product reaches 99.999% or more, the total hydrocarbon content in the product exceeds the standard, and an electronic-grade carbon dioxide product cannot be obtained. This indicates that the method of the present invention, using modified activated carbon for dehydrogenation, has a good dehydrogenation effect on epoxy decarbonization regeneration gas with a total hydrocarbon content of less than or equal to 0.7 Vol% and an alkylene oxide content of less than or equal to 10 ppm, thereby obtaining high-quality electronic-grade carbon dioxide.

[0083] In addition, Example 9 changed the specific surface area and average particle size of the activated carbon in the modified activated carbon, Example 10 changed the average pore size and porosity of the activated carbon in the modified activated carbon, Examples 11-13 all changed the type of metal particles loaded on the modified activated carbon, Example 14 changed the content of copper and magnesium particles in the modified activated carbon, and Example 15 changed the average particle size of copper and magnesium particles in the modified activated carbon. Although the resulting carbon dioxide products all met electronic grade standards, the total hydrocarbon content increased compared to Example 1. This indicates that the properties of the activated carbon in the modified activated carbon, the type, content, and average particle size of the loaded metal particles all affect the dehydrogenation effect.

[0084] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing electronic grade carbon dioxide, characterized in that: The preparation method comprises: compressing the gas phase obtained by gas-liquid separation of epoxy decarbonization regeneration gas, then dehydrogenating the obtained compressed gas, and then drying, liquefying and purifying the obtained dehydrogenated gas to obtain the electronic grade carbon dioxide; The content of total hydrocarbons in the epoxy decarbonization regeneration gas is less than or equal to 0.7 Vol%, and the content of epoxy alkylene is less than or equal to 10 ppm. The decarbonization method comprises: contacting the compressed gas with modified activated carbon; The modified activated carbon comprises activated carbon and metal particles loaded in the pores of the activated carbon; the metal particles are selected from copper particles and / or magnesium particles; the specific surface area of ​​the activated carbon is 1000-3000m 2 / g, with an average particle size of 1-5 mm, an average pore size of 3-30 nm, and a porosity of 0.7-0.9 cm 3 / g; in the modified activated carbon, the average particle size of the copper particles is 3-10nm, and the average particle size of the magnesium particles is 5-20nm; based on the total weight of the modified activated carbon, the contents of the copper particles and the magnesium particles in the modified activated carbon are 0.8-1.5wt% and 0.3-0.9wt%, respectively.

2. The preparation method according to claim 1, wherein The metal particles are copper particles and magnesium particles.

3. The preparation method according to claim 1, wherein The specific surface area of ​​the activated carbon is 1800-2500m 2 / g; the average particle size is 2-4mm.

4. The preparation method according to claim 1, wherein The activated carbon has an average pore diameter of 25-30 nm and a porosity of 0.8-0.9 cm 3 / g.

5. The preparation method according to any one of claims 1 to 4, wherein The compression method includes: pressurizing the gas phase obtained by gas-liquid separation to 2.3-3 MPa.

6. The preparation method according to any one of claims 1 to 4, wherein During the dehydrogenation process, based on the total volume of the epoxy decarbonization regeneration gas being 1 L, the amount of the modified activated carbon used is 30-60 g.

7. The preparation method according to any one of claims 1 to 4, wherein The dehydrogenation process includes: contacting the compressed gas with the modified activated carbon at 35-45° C. for 10-30 minutes.

8. The preparation method according to any one of claims 1 to 4, wherein The drying method includes: contacting the dehydrocarbon gas with a molecular sieve.

9. The preparation method according to claim 8, wherein The molecular sieve has pores with an average pore diameter of 0.3-0.5 nm.

10. The preparation method according to any one of claims 1 to 4, wherein The liquefaction conditions include: the refrigeration medium is carbon dioxide, and the refrigeration temperature is -25°C to -10°C.

11. The preparation method according to any one of claims 1 to 4, wherein The purification method includes: distilling the liquefied product obtained by liquefaction.

12. The preparation method according to claim 11, wherein The distillation conditions include: temperature of -22°C to -15°C and pressure of 1.5-2.1 MPa.

13. A device for preparing electronic grade carbon dioxide, characterized in that: The device comprises: a coalescing separator, a compressor, an adsorption tower, a drying tower, a refrigerator and a distillation tower which are connected in sequence; The coalescing separator is used to separate the epoxy decarbonization regeneration gas into gas and liquid; the compressor is used to compress the gas phase obtained by the gas-liquid separation; the adsorption tower is used to dehydrogenate the compressed gas; the drying tower is used to dry the dehydrogenated gas obtained by the dehydrogenation; the refrigerator is used to liquefy the dried gas; and the distillation tower is used to purify the liquefied product to obtain electronic grade carbon dioxide. The adsorption tower is filled with modified activated carbon; the modified activated carbon comprises activated carbon and metal particles loaded in the pores of the activated carbon; the metal particles are selected from copper particles and / or magnesium particles; the specific surface area of ​​the activated carbon is 1000-3000m 2 / g, with an average particle size of 1-5 mm, an average pore size of 3-30 nm, and a porosity of 0.7-0.9 cm 3 / g; in the modified activated carbon, the average particle size of the copper particles is 3-10nm, and the average particle size of the magnesium particles is 5-20nm; based on the total weight of the modified activated carbon, the contents of the copper particles and the magnesium particles in the modified activated carbon are 0.8-1.5wt% and 0.3-0.9wt%, respectively.

14. The device according to claim 13, wherein The drying tower is filled with molecular sieves.

15. The device according to claim 13, wherein The device comprises two groups of adsorption towers and two groups of drying towers.

16. The device according to any one of claims 13 to 15, wherein: The filtration accuracy of the filter element in the coalescing separator is 0.1-1µm.

17. The device according to any one of claims 13 to 15, wherein: The distillation tower is connected to the adsorption tower and the drying tower respectively. The gas phase flowing out of the distillation tower is mixed with the dehydrogenated gas flowing out of the adsorption tower and then enters the drying tower.

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