Preparation method of electronic-grade carbon dioxide

Abstract

The present invention provides an electronic grade carbon dioxide preparation method, which comprises: a conversion process: mixing crude carbon dioxide, an alkali solution and a catalyst, and carrying out a reaction to obtain a bicarbonate solution, the catalyst being used for catalyzing the conversion of carbon dioxide into bicarbonate radicals; a mixing step in which the bicarbonate solution and a solution containing a reducing substance are mixed to obtain an electrolyte solution; an electrolysis step in which the electrolyte solution is electrolyzed to obtain an anode gas containing carbon dioxide; and a separation step of separating the anode gas to obtain the electronic-grade carbon dioxide. The preparation method not only has lower energy consumption, but also has higher carbon dioxide recovery rate.

Description

Technical Field

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

[0002] Electronic grade carbon dioxide usually refers to carbon dioxide gas with a purity of more than 99.999%, which is used in the fields of semiconductors, electronics, optoelectronics and chemical processing. At present, the preparation of electronic grade carbon dioxide usually uses carbon dioxide-rich gas as raw material, which also contains impurity gases such as oxygen and nitrogen. In the relevant technology, the preparation of electronic grade carbon dioxide has high energy consumption and low recovery rate. Therefore, it is urgent to develop a method for preparing electronic grade carbon dioxide with low energy consumption and high recovery rate. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for preparing electronic grade carbon dioxide, which has not only lower energy consumption but also higher carbon dioxide recovery rate.

[0004] An embodiment of the present invention provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0005] a conversion step, mixing crude carbon dioxide, an alkaline solution and a catalyst and reacting them to obtain a bicarbonate solution, wherein the catalyst is used to catalyze the conversion of carbon dioxide into bicarbonate;

[0006] A mixing step of mixing the bicarbonate solution and a solution containing a reducing substance to obtain an electrolyte solution;

[0007] An electrolysis step of electrolyzing the electrolyte solution to obtain anode gas containing carbon dioxide;

[0008] The separation step is to separate the anode gas to obtain electronic grade carbon dioxide.

[0009] According to any of the aforementioned embodiments of the present invention, the conversion step comprises:

[0010] a capture step of mixing the first portion of crude carbon dioxide with an alkaline solution to obtain a carbonate solution;

[0011] The conversion step comprises mixing the carbonate solution, the second portion of crude carbon dioxide and a catalyst and reacting them to obtain a bicarbonate solution, wherein the catalyst is used to catalyze the conversion of carbon dioxide into bicarbonate.

[0012] According to any of the foregoing embodiments of the present invention, the catalyst comprises carbonic anhydrase.

[0013] According to any of the aforementioned embodiments of the present invention, the gas-to-solid ratio of the crude carbon dioxide to the carbonic anhydrase is 1L:(0.02-0.1)g.

[0014] According to any of the aforementioned embodiments of the present invention, in the conversion step, the reaction temperature is 40° C. to 60° C.; and / or the reaction pH is 7 to 9.

[0015] According to any of the aforementioned embodiments of the present invention, in the mixing step, the reducing substance includes ferrous ions and / or vitamins.

[0016] According to any of the aforementioned embodiments of the present invention, the mass ratio of the reducing substance to the bicarbonate solution is 1:(0.5-0.8).

[0017] According to any of the aforementioned embodiments of the present invention, in the electrolysis step, the temperature of the electrolysis treatment is 50°C to 70°C, the voltage is 1.5V to 3V, and the current density is 1000A / m 2 ~6000A / m 2 .

[0018] According to any of the aforementioned embodiments of the present invention, in the electrolysis step, an electrode made of graphite is used as the anode electrode.

[0019] According to any of the foregoing embodiments of the present invention, the separation step comprises:

[0020] a cooling step of cooling the anode gas to obtain a mixture;

[0021] a gas-liquid separation step, performing a gas-liquid separation process on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0022] a drying step of drying the mixed gas to obtain carbon dioxide gas;

[0023] a liquefaction step, liquefying the carbon dioxide gas to obtain liquid carbon dioxide;

[0024] The distillation step is to distill the liquid carbon dioxide to obtain electronic grade carbon dioxide.

[0025] According to any of the aforementioned embodiments of the present invention, the alkaline solution contains at least one of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0026] According to any of the aforementioned embodiments of the present invention, the purity of carbon dioxide in the crude carbon dioxide is 70% to 99.99%.

[0027] The present invention provides a method for preparing electronic-grade carbon dioxide. By adding a catalyst for catalyzing the conversion of carbon dioxide into bicarbonate in the conversion process, it can help improve the conversion efficiency of carbon dioxide into bicarbonate, thereby helping to reduce the energy consumption of electrolysis and improve the recovery rate of carbon dioxide. In addition, by mixing the bicarbonate solution obtained in the conversion process with a solution containing a reducing substance to form an electrolyte solution, while reducing the energy consumption of electrolysis, the oxidizing and reducing substances generated at the anode can react to reduce the impurity gas in the anode gas to obtain high-purity electronic-grade carbon dioxide. Therefore, the present invention provides a method for preparing electronic-grade carbon dioxide with lower energy consumption and higher carbon dioxide recovery rate.

[0028] The above description is only an overview of the technical solution of this specification. In order to more clearly understand the technical means of this specification, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of this specification more obvious and easy to understand, the specific implementation methods of this specification are listed below. DETAILED DESCRIPTION

[0029] The following embodiments describe the disclosure of the present invention in more detail, and these embodiments are only used for illustrative description, because it is obvious to those skilled in the art that various modifications and changes are made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods, and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0030] Example 1

[0031] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0032] (1) 11.95 L of crude carbon dioxide with a purity of 75%, 22 g of an aqueous sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted at a pH of 13 to obtain a sodium bicarbonate solution;

[0033] (2) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0034] (3) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0035] (4) cooling the anode gas at 10° C. to obtain a mixture;

[0036] (5) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0037] (6) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0038] (7) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0039] (8) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0040] Example 2

[0041] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0042] (1) 11.95 L of crude carbon dioxide with a purity of 75%, 22 g of a sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) and 0.3 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted at a pH of 13 to obtain a sodium bicarbonate solution;

[0043] (2) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0044] (3) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0045] (4) cooling the anode gas at 10° C. to obtain a mixture;

[0046] (5) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0047] (6) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0048] (7) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0049] (8) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0050] Example 3

[0051] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0052] (1) 11.95 L of crude carbon dioxide with a purity of 75%, 22 g of an aqueous ammonia solution (0.65 mol / L) and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted at a pH of 11 to obtain a sodium bicarbonate solution;

[0053] (2) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0054] (3) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0055] (4) cooling the anode gas at 10° C. to obtain a mixture;

[0056] (5) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0057] (6) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0058] (7) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0059] (8) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0060] Example 4

[0061] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0062] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0063] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0064] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0065] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0066] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0067] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0068] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0069] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0070] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0071] Example 5

[0072] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0073] (1) 7 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 8;

[0074] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0075] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0076] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0077] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0078] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0079] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0080] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0081] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0082] Example 6

[0083] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0084] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0085] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0086] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 15.4 g of vitamin C (the concentration of vitamin C is 0.0875 mol / L) to obtain an electrolyte solution;

[0087] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0088] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0089] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0090] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0091] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0092] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0093] Example 7

[0094] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0095] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0096] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0097] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 19.5 g of vitamin C (the concentration of vitamin C is 0.11 mol / L) to obtain an electrolyte solution;

[0098] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0099] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0100] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0101] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0102] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0103] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0104] Example 8

[0105] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0106] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0107] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.08 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0108] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0109] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0110] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0111] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0112] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0113] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0114] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0115] Example 9

[0116] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0117] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0118] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.68 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0119] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0120] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0121] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0122] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0123] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0124] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0125] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0126] Example 10

[0127] This embodiment provides a method for preparing electronic grade carbon dioxide, the preparation method comprising:

[0128] (1) 6 L of crude carbon dioxide with a purity of 75% and 22 g of sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed to obtain a sodium carbonate solution with a pH of 9;

[0129] (2) the sodium carbonate solution, 6 L of crude carbon dioxide having a purity of 75%, and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted to obtain a sodium bicarbonate solution;

[0130] (3) mixing the sodium bicarbonate solution and an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0131] (4) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 60° C., the electrolysis voltage is 3 V, and the current density is 3000 A / m 2 ;

[0132] (5) cooling the anode gas at 10° C. to obtain a mixture;

[0133] (6) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0134] (7) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0135] (8) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0136] (9) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0137] Comparative Example 1

[0138] This comparative example provides a method for preparing electronic grade carbon dioxide, which comprises:

[0139] (1) 11.95 L of crude carbon dioxide having a purity of 75% and 22 g of a sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed and reacted at a pH of 13 to obtain a mixed solution;

[0140] (2) mixing the mixed solution with an aqueous solution containing 16.8 g of vitamin C (the concentration of vitamin C is 0.095 mol / L) to obtain an electrolyte solution;

[0141] (3) The electrolyte solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0142] (4) cooling the anode gas at 10° C. to obtain a mixture;

[0143] (5) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0144] (6) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0145] (7) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0146] (8) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0147] Comparative Example 2

[0148] This comparative example provides a method for preparing electronic grade carbon dioxide, which comprises:

[0149] (1) 11.95 L of crude carbon dioxide with a purity of 75%, 22 g of a sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) and 0.18 g of carbonic anhydrase (brand name: Amresco) were mixed and reacted at a pH of 13 to obtain a sodium bicarbonate solution;

[0150] (2) The sodium bicarbonate solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45° C., the electrolysis voltage is 2 V, and the current density is 2000 A / m 2 ;

[0151] (3) cooling the anode gas at 10° C. to obtain a mixture;

[0152] (4) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water, wherein the purity of carbon dioxide in the mixed gas is measured to be 99.99%;

[0153] (5) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0154] (6) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0155] (7) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0156] Comparative Example 3

[0157] This comparative example provides a method for preparing electronic grade carbon dioxide, which comprises:

[0158] (1) 11.95 L of crude carbon dioxide having a purity of 75% and 22 g of a sodium hydroxide solution (the concentration of sodium hydroxide is 0.55 mol / L) are mixed and reacted at a pH of 13 to obtain a mixed solution;

[0159] (2) The mixed solution is electrolyzed to obtain anode gas containing carbon dioxide, wherein the electrolysis temperature is 45°C, the electrolysis voltage is 2V, and the current density is 2000A / m 2 ;

[0160] (3) cooling the anode gas at 10° C. to obtain a mixture;

[0161] (4) performing gas-liquid separation on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water;

[0162] (5) drying the mixed gas at 80° C. to obtain carbon dioxide gas;

[0163] (6) liquefying the carbon dioxide gas at -10°C to obtain liquid carbon dioxide;

[0164] (7) The liquid carbon dioxide is sequentially passed through a reboiler, a condenser and a distillation tower to obtain electronic grade carbon dioxide.

[0165] Test Section

[0166] (1) Oxygen concentration test

[0167] The detection method is in accordance with the method specified in "Gas Carbon Dioxide for Electronic Industry" (GB / T23938-2009). The test results are shown in Table 1.

[0168] (2) Measurement of bicarbonate concentration

[0169] The concentration of bicarbonate in the sodium bicarbonate solution or mixed solution in the embodiments and comparative examples was measured using an XS-HCO3 type bicarbonate ion concentration meter.

[0170] Table 1 lists the test results of Examples 1-10 and Comparative Examples 1-3 respectively.

[0171] Table 1 Test results of Examples 1-10 and Comparative Examples 1-3

[0172]

[0173]

[0174] According to Table 1, by comparing the test results of Examples 1-10 and Comparative Examples 1-3, it can be seen that the method for preparing an electronic-grade carbon dioxide provided by the present invention can help improve the conversion efficiency of carbon dioxide to bicarbonate by adding a catalyst for catalyzing the conversion of carbon dioxide to bicarbonate in the conversion process, thereby helping to reduce the energy consumption of electrolysis and improve the recovery rate of carbon dioxide. In addition, by mixing the bicarbonate solution obtained in the conversion process with a solution containing a reducing substance to form an electrolyte solution, while being able to reduce the energy consumption of electrolysis, the oxidizing property generated by the anode can also be reacted with the reducing substance to reduce the impurity gas in the anode gas, so as to obtain high-purity electronic-grade carbon dioxide. Therefore, the method for preparing an electronic-grade carbon dioxide provided by the present invention has lower energy consumption and higher recovery rate of carbon dioxide.

[0175] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned experimental examples, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned experimental examples, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the experimental examples of the present invention.

Claims

1. A method for preparing electronic grade carbon dioxide, characterized in that: The preparation method comprises: a conversion step, mixing crude carbon dioxide, an alkaline solution and a catalyst and reacting them to obtain a bicarbonate solution, wherein the catalyst is used to catalyze the conversion of carbon dioxide into bicarbonate; A mixing step of mixing the bicarbonate solution and a solution containing a reducing substance to obtain an electrolyte solution; An electrolysis step of electrolyzing the electrolyte solution to obtain anode gas containing carbon dioxide; The separation step is to separate the anode gas to obtain electronic grade carbon dioxide.

2. The preparation method according to claim 1, characterized in that: The conversion process comprises: a capture step of mixing the first portion of crude carbon dioxide with an alkaline solution to obtain a carbonate solution; The conversion step comprises mixing the carbonate solution, the second portion of crude carbon dioxide and a catalyst and reacting them to obtain a bicarbonate solution, wherein the catalyst is used to catalyze the conversion of carbon dioxide into bicarbonate.

3. The preparation method according to claim 1, characterized in that: The catalyst includes carbonic anhydrase.

4. The preparation method according to claim 3, characterized in that: The gas-to-solid ratio of the crude carbon dioxide to the carbonic anhydrase is 1L:(0.02-0.1)g.

5. The preparation method according to claim 3, characterized in that: In the conversion step, the reaction temperature is 40°C to 60°C; and / or the reaction pH is 7 to 9.

6. The preparation method according to claim 1, characterized in that: In the mixing step, the reducing substance includes ferrous ions and / or vitamins.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the reducing substance to the bicarbonate solution is 1:(0.5-0.8).

8. The preparation method according to claim 1, characterized in that: In the electrolysis process, the temperature of the electrolysis treatment is 50°C to 70°C, the voltage is 1.5V to 3V, and the current density is 1000A / m 2 ~6000A / m 2 .

9. The preparation method according to claim 1, characterized in that: In the electrolysis step, a graphite electrode is used as the anode electrode.

10. The preparation method according to claim 1, characterized in that: The separation process comprises: a cooling step of cooling the anode gas to obtain a mixture; a gas-liquid separation step, performing a gas-liquid separation process on the mixture to obtain a mixed gas containing carbon dioxide and water vapor and condensed water; a drying step of drying the mixed gas to obtain carbon dioxide gas; a liquefaction step, liquefying the carbon dioxide gas to obtain liquid carbon dioxide; The distillation step is to distill the liquid carbon dioxide to obtain electronic grade carbon dioxide.

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