Method for decomposing fluorinated gas using metal mixture

Abstract

The present invention relates to a method for decomposing fluorinated gas using a metal mixture. The present invention does not generate harmful by-products, and thus requires no separate post-treatment process, and can decompose fluorinated gas at a higher decomposition rate under a milder condition than existing decomposition methods.

Description

Method for decomposing fluorinated gases using metal mixtures

[0001] The present invention relates to a method for decomposing fluorinated gases using a metal mixture. This invention claims the benefit of Korean Patent Application No. 10-2024-0026929, filed with the Korean Intellectual Property Office on February 26, 2024, the entire contents of which are incorporated herein by reference.

[0002] The United Nations Framework Convention on Climate Change, which aims to regulate and prevent global warming, proposed reductions in CO2, CH4, N2O, PFC (Perfluorocarbon), HFC (Hydrofluorocarbon), and SF6 through the adoption of the Kyoto Protocol in 1997. NF3 was added at the 2012 Doha Conference, and the 2015 Paris Agreement expanded the scope of greenhouse gas reduction obligations from existing developed countries to 195 countries.

[0003] Previously, plasma combustion or catalytic combustion was used to decompose greenhouse gases such as PFC, HFC, SF6, and NF3. Specifically, in order to decompose CF4 among greenhouse gases, plasma combustion is used at a temperature of 1300℃ or higher, and catalytic combustion is used at a temperature of 700℃ to 800℃, and CF4 is thermally decomposed, and CO, CO2, NO x , SO x , and generates by-products such as HF. Therefore, an additional post-treatment process is required to treat the by-products, and in particular, when post-treating toxic HF using a wet treatment method, there is a problem that a large amount of chemicals and water are used.

[0004] The problem to be solved by the present invention is to provide a method for decomposing fluorinated gases with a high decomposition rate under milder conditions than existing decomposition methods of fluorinated gases, without the need for a separate post-treatment process because no harmful by-products are generated.

[0005] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0006] According to one aspect of the present invention, a method for decomposing a fluorinated gas is provided, comprising: a step of filling a metal mixture including a first metal and a second metal into a reaction rod; and a step of performing a heat treatment while passing a fluorinated gas through the reaction rod; wherein the first metal and the second metal are different from each other and are each independently at least one selected from Cu, Ni, Sn, Co, Fe, Zn, Cr, Ti, Mn, Si, Zr, Al, K, Na, Mg, Li, Ca, Sr, Ba, Sc, and Y.

[0007] A method for decomposing fluorinated gas according to one embodiment of the present invention can decompose fluorinated gas at a higher decomposition rate under milder conditions than existing decomposition methods.

[0008] Since the method for decomposing fluorinated gas according to one embodiment of the present invention does not produce harmful byproducts after decomposition of fluorinated gas, a separate post-treatment process may not be performed.

[0009] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from the specification herein.

[0010] Figure 1 is a diagram illustrating a method for decomposing fluorinated gas according to the present invention.

[0011] Figure 2 shows the decomposition rate of fluorinated gas at 625°C according to the titanium mole fraction of the filled metal mixture.

[0012] Figure 3 shows the decomposition rates of fluorinated gases of Example 1, Example 2-1, Example 3-1, and Comparative Example 1 according to the heat treatment temperature.

[0013] Figure 4 shows the decomposition rates of fluorinated gases of Examples 3-1, 4, 5, and Comparative Example 2 according to heat treatment temperature.

[0014] Figure 5 shows the decomposition rates of fluorinated gases of Examples 2-2 and 3-2 according to the heat treatment temperature.

[0015] Figure 6 shows the decomposition rate of fluorinated gas of Example 6 according to the heat treatment temperature.

[0016] When a part in this specification is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0017] Throughout this specification, the unit "mol%" may mean the mole ratio of each component relative to the whole (100 mol%). For example, in a metal mixture, 75 mol% Mg means that Mg accounts for 75 mol% of the total metal mixture (100 mol%).

[0018] Throughout this specification, “A and / or B” means “A, B, or A and B.”

[0019] Throughout the present specification, “filling ratio” may mean the volume of filled particles or metals per unit volume of 1. For example, “filling ratio of the first metal and the second metal” of the present invention means the volume of the filled first metal and the second metal per unit volume of the reaction rod.

[0020]

[0021] Hereinafter, the present invention will be described in more detail.

[0022]

[0023] One embodiment of the present invention provides a method for decomposing (removing) a fluorinated gas, comprising the steps of: filling a metal mixture including a first metal and a second metal into a reaction rod; and performing a heat treatment while passing a fluorinated gas through the reaction rod; wherein the first metal and the second metal are different from each other and are each independently at least one selected from Cu, Ni, Sn, Co, Fe, Zn, Cr, Ti, Mn, Si, Zr, Al, K, Na, Mg, Li, Ca, Sr, Ba, Sc, and Y.

[0024] Figure 1 is a diagram illustrating a method for decomposing fluorinated gas according to the present invention.

[0025] Referring to Figure 1, the fluorine gas may pass through the interior of a reaction rod filled with a metal mixture including a first metal and a second metal that is undergoing heat treatment, and react with the metal mixture including the first metal and the second metal to decompose (remove) the fluorine gas.

[0026] According to one embodiment of the present invention, the first metal and the second metal are different from each other, and the first metal may be at least one selected from Cu, Ni, Sn, Co, Fe, Zn, Cr, Ti, Mn, Si, Zr, Al, K, Na, Mg, Li, Ca, Sr, Ba, Sc and Y, and the second metal may be at least one selected from Li, Mn, Cr, Al, Ca, Si, Ti and Zr. The first metal may be one that combines with fluorine (F), and the second metal may be one that combines with carbon (C), nitrogen (N) or sulfur (S), which are elements other than fluorine of the fluorinated gas, to decompose (remove) the fluorinated gas.

[0027] According to one embodiment of the present invention, the molar ratio of the first metal and the second metal may be 5:1 to 1:5. Specifically, the molar ratio of the first metal and the second metal may be 5:1 to 1:5, 3:1 to 1:5, 5:1 to 1:3, 3:1 to 1:3, 2:1 to 1:5, or 2:1 to 1:3. When the molar ratio of the first metal and the second metal is within the above-mentioned range, the decomposition rate of the fluorinated gas may be excellent.

[0028] According to one embodiment of the present invention, the filling ratio of the first metal and the second metal may be 0.2 to 0.8. Specifically, the filling ratio of the first metal and the second metal may be 0.2 to 0.8, 0.2 to 0.65, 0.2 to 0.5, 0.2 to 0.4, or 0.2 to 0.3. When the filling ratio of the first metal and the second metal is within the above-mentioned range, the decomposition rate of the fluorinated gas may be excellent.

[0029] According to one embodiment of the present invention, the first metal and the second metal may be independently filled in the form of turning, sponge, and granule, respectively. Since the first metal and the second metal are filled in the aforementioned form, the fluorinated gas can pass through the inside of the reaction rod while reacting with the first metal and the second metal, thereby easily decomposing the fluorinated gas.

[0030] According to one embodiment of the present invention, the filling density of the metal mixture is 0.6 g / cm 3 3.6 g / cm 3 It may be. Specifically, the filling density of the metal mixture is 0.6 g / cm 3 3.6 g / cm 3 , 0.6 g / cm 3 3.6 g / cm 3 , 0.6 g / cm 3 3.0 g / cm 3 , 0.6 g / cm 32.5 g / cm 3 , 0.6 g / cm 3 2.0 g / cm 3 , 0.6 g / cm 3 1.5 g / cm 3 , 0.6 g / cm 3 1.0 g / cm 3 , 0.6 g / cm 3 0.8 g / cm 3 , 0.62 g / cm 3 0.8 g / cm 3 , 0.65 g / cm 3 0.8 g / cm 3 , 0.67 g / cm 3 0.8 g / cm 3 , 0.7 g / cm 3 0.8 g / cm 3 , 0.6 g / cm 3 0.74 g / cm 3 , 0.62 g / cm 3 0.74 g / cm 3 , 0.65 g / cm 3 0.74 g / cm 3 , 0.67 g / cm 3 0.74 g / cm 3 or 0.7 g / cm 3 0.74 g / cm 3 It can be. When the filling density of the above metal mixture is within the above-mentioned range, the decomposition rate of fluorinated gas can be excellent.

[0031] According to one embodiment of the present invention, the filling length of the metal mixture may be 100 mm to 1000 mm. Specifically, the filling length of the metal mixture may be 100 mm to 1000 mm, 100 mm to 800 mm, 100 mm to 600 mm, 200 mm to 1000 mm, 200 mm to 800 mm, 200 mm to 600 mm, or 300 mm to 500 mm. When the filling length of the metal mixture is in the above-mentioned range, the decomposition rate of the fluorinated gas may be excellent. When the filling length is smaller than the above-mentioned range, the fluorinated gas may not react with the metal mixture, but may pass through and not be decomposed.

[0032] According to one embodiment of the present invention, the fluorinated gas may be at least one selected from perfluorocarbon gas, hydrofluorocarbon gas, NF3, and SF6. Specifically, the perfluorocarbon gas may be a C1-C8 alkyl in which all hydrogens are replaced with fluorine, and the hydrofluorocarbon gas may be a C1-C8 alkyl in which some of the hydrogens are replaced with fluorine. More specifically, the perfluorocarbon gas may be CF4, C2F6, C3F8, C4F 10 It can be, and the hydrofluoric gas is CHF3 (HFC-23), CH2F2 (HFC-134a), CH3CF3 (HFC-143a), CH3CHF2 (HFC-152a), CH2F2 (HFC-32), CHF2CF3 (HFC-125), CH2FCF3 (HFC-134), CF3CHFCF3 (HFC-227ea) It can be. The existing plasma combustion method or combustion method using a catalyst decomposes fluorinated gas as shown in the following reaction formulas 1 to 3 and produces harmful CO, CO2, NO. x , SO x , HF, etc., so a post-treatment process is required, but the method for decomposing fluorinated gas using the metal mixture of the present invention is as shown in the following reaction scheme 4, the first metal (M 1) combines with fluorine, and the second metal (M 2 ) can combine with elements other than fluorine without producing harmful byproducts such as HF.

[0033] [Reaction Formula 1]

[0034] CF4+ H2O -> HF + CO + CO2

[0035] [Reaction Formula 2]

[0036] NF3+ H2O -> HF + NO x

[0037] [Reaction Formula 3]

[0038] SF6+ H2O -> HF + SO x

[0039] [Reaction Formula 4]

[0040] CF4+ M 1 + M 2 -> M 1 F n + M 2 C

[0041] According to one embodiment of the present invention, the concentration of the fluorinated gas may be 20 ppm to 20,000 ppm. The fluorinated gas may be mixed with a gas having low reactivity with the mixture of the first metal and the second metal, such as nitrogen (N2), and / or a gas that does not react with the mixture of the first metal and the second metal, such as helium (He), argon (Ar), and the like, and injected into the reaction rod. Specifically, the concentration of the fluorinated gas may be 20 ppm to 20,000 ppm, 20 ppm to 10,000 ppm, 20 ppm to 7,500 ppm, 20 ppm to 5,000 ppm, 20 ppm to 3,000 ppm, 100 ppm to 20,000 ppm, 100 ppm to 10,000 ppm, 100 ppm to 7,500 ppm, 100 ppm to 5,000 ppm, 100 ppm to 3,000 ppm, 1000 ppm to 20,000 ppm, 1000 ppm to 10,000 ppm, 1000 ppm to 7,500 ppm, 1000 ppm to 5,000 ppm, or 1000 ppm to 3,000 ppm. When the concentration of the fluorinated gas is within the aforementioned range, the decomposition rate of the fluorinated gas may be excellent. On the other hand, when the concentration of the fluorinated gas is lower than the aforementioned range, the reaction efficiency between the fluorinated gas and the metal mixture may be reduced, and when the concentration of the fluorinated gas is higher than the aforementioned range, the fluorinated gas may not be sufficiently removed by the reaction between the fluorinated gas and the metal mixture, and thus the decomposition rate of the fluorinated gas may be low.

[0042] According to one embodiment of the present invention, the heat treatment may be performed at 500°C to 1000°C. Specifically, the heat treatment temperature may be performed at a temperature lower than the melting points of the first metal and the second metal. More specifically, the heat treatment temperature may be 500°C to 1000°C, 500°C to 900°C, 500°C to 800°C, 500°C to 700°C, 500°C to 650°C, 500°C to 625°C, 525°C to 800°C, 525°C to 700°C, 525°C to 650°C, or 525°C to 625°C. When the heat treatment temperature is within the above-mentioned range, the decomposition rate of the fluorinated gas may be excellent. On the other hand, if the heat treatment temperature is lower than the above-mentioned range, the decomposition rate of the fluorinated gas may be low, and if the heat treatment temperature is higher than the above-mentioned range, the first metal and / or second metal included in the metal mixture may melt, resulting in a low decomposition rate of the fluorinated gas.

[0043] Hereinafter, the present invention will be described in detail with examples and experimental examples to specifically explain the present invention. However, the examples and experimental examples according to the present invention may be modified in various different forms, and the scope of the present invention is not construed as being limited to the examples and experimental examples described below. The examples and experimental examples in this specification are provided to more fully explain the present invention to those of average skill in the art.

[0044]

[0045] Example 1. Decomposition of fluorinated gas using a metal mixture (Mg + Ti)

[0046] A 400 mm long reaction rod filled with a metal mixture was manufactured by compressing 75 mol% of magnesium (Mg) in a turning form and 25 mol% of titanium (Ti) in a sponge form into a STS304 reaction rod having a length of 1 m and an inner diameter of 1.5 inches, and then placed in an electric furnace.

[0047] Nitrogen (N2) mixed with CF4 at a concentration of 2000 ppm was passed through the reaction rod filled with the above metal mixture at a flow rate of 0.1 LPM, and the fluorinated gas (CF4) was decomposed by heat treatment.

[0048]

[0049] Examples 2 to 5, Comparative Examples 1-1 and 1-2

[0050] Fluorinated gas was decomposed in the same manner as in Example 1, except that the magnesium content, titanium content, packing density, and Mg:Ti packing ratio were adjusted as shown in Table 1 below.

[0051] Magnesium content (mol%)Titanium content (mol%)Filling density (g / cm 3 ) Filling ratio of Mg and Ti Example 175250.640.28 Example 2-166.633.30.670.27 Example 2-266.633.30.710.28 Example 3-150500.730.25 Example 3-250500.790.27 Example 433.366.60.720.21 Example 525750.770.21 Comparative Example 110000.570.33 Comparative Example 201000.750.17

[0052] Example 6. Decomposition of fluorinated gas using a metal mixture (Ca + Ti)

[0053] Fluorinated gas was decomposed in the same manner as in Example 1, except that the calcium (Ca) content, titanium content, packing density, and Ca:Ti packing ratio were adjusted as shown in Table 2 below.

[0054] Calcium content (mol%)Titanium content (mol%)Filling density (g / cm3 )Ca and Ti filling ratio example 666.633.30.750.36

[0055] Experimental Example 1. Evaluation of the decomposition rate of fluorinated gases

[0056] In the above Examples 1 to 6 and Comparative Examples 1 and 2, the nitrogen from which the fluorinated gas was decomposed (removed) was evaluated through gas chromatography, and the results are shown in FIGS. 2 to 5.

[0057] Fig. 2 shows the fluorine gas decomposition rate at 625°C according to the titanium mole fraction of the filled metal mixture, Fig. 3 shows the fluorine gas decomposition rate of Example 1, Example 2-1, Example 3-1 and Comparative Example 1 according to the heat treatment temperature, and Fig. 4 shows the fluorine gas decomposition rate of Example 3-1, Example 4, Example 5 and Comparative Example 2 according to the heat treatment temperature.

[0058] Referring to FIGS. 2, 3, and 4, it was confirmed that in Examples 1, 2-1, 3-1, 4, and 5 using a metal mixture including magnesium and titanium, fluorinated gas was decomposed by 90% or more at 625°C. In particular, in Examples 2-1 (Mg:Ti=2:1), 3-1 (Mg:Ti=1:1), 4 (Mg:Ti=1:2), and 5 (Mg:Ti=1:3), fluorinated gas was decomposed by 99% or more at 625°C.

[0059] On the other hand, it was confirmed that in Comparative Example 1 (Mg 100 mol%), fluorinated gas was decomposed by less than 80% at 625°C, and in Comparative Example 2 (Ti 100 mol%), fluorinated gas was decomposed by less than 30% at 625°C.

[0060] Figure 5 shows the decomposition rates of fluorinated gases of Examples 2-2 and 3-2 according to heat treatment temperature.

[0061] Referring to Figures 2 and 5, Example 2-1 (filling density 0.67 g / cm 3), Example 2-2 (filling density 0.71 g / cm 3 ), Example 3-1 (filling density 0.73 g / cm 3 ) and Example 3-2 (filling density 0.79 g / cm 3 ) is 0.67 g / cm 3 0.79 g / cm 3 It was confirmed that fluorinated gas was decomposed by more than 99% at the filling density.

[0062] Figure 6 shows the decomposition rate of fluorinated gas of Example 6 according to the heat treatment temperature.

[0063] As shown in Fig. 6, Example 6 using a metal mixture containing calcium and titanium confirmed that fluorinated gas was decomposed by more than 99% at 525°C.

[0064] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. A step of filling a metal mixture containing a first metal and a second metal into the inside of a reaction rod; and A step of heat treatment while passing fluorinated gas through the inside of the reaction rod; A method for decomposing fluorinated gas, wherein the first metal and the second metal are different from each other and are each independently at least one selected from Cu, Ni, Sn, Co, Fe, Zn, Cr, Ti, Mn, Si, Zr, Al, K, Na, Mg, Li, Ca, Sr, Ba, Sc and Y.

2. In paragraph 1, A method for decomposing fluorinated gas, wherein the molar ratio of the first metal and the second metal is 5:1 to 1:

5.

3. In paragraph 1, A method for decomposing fluorinated gas, wherein the filling ratio of the first metal and the second metal is 0.2 to 0.

8.

4. In paragraph 1, A method for decomposing fluorinated gas, wherein the first metal and the second metal are each independently filled in the form of turning, sponge, and granule.

5. In paragraph 1, The filling density of the above metal mixture is 0.6 g / cm 3 3.6 g / cm 3 A method for decomposing fluorinated gas.

6. In paragraph 1, A method for decomposing a fluorinated gas, wherein the fluorinated gas is at least one selected from perfluorocarbon gas, hydrofluorocarbon gas, NF3, and SF6.

7. In paragraph 1, A method for decomposing fluorinated gas, wherein the concentration of the fluorinated gas is 20 ppm to 20,000 ppm.

8. In paragraph 1, A method for decomposing fluorinated gas, wherein the above heat treatment is performed at 500°C to 1000°C.

9. In paragraph 1, A method for decomposing fluorinated gas, wherein the first metal is at least one selected from Cu, Ni, Sn, Co, Fe, Zn, Cr, Ti, Mn, Si, Zr, Al, K, Na, Mg, Li, Ca, Sr, Ba, Sc and Y.

10. In paragraph 9, A method for decomposing fluorinated gas, wherein the first metal combines with fluorine (F) of the fluorinated gas.

11. In paragraph 1, A method for decomposing fluorinated gas, wherein the second metal is at least one selected from Li, Mn, Cr, Al, Ca, Si, Ti, and Zr.

12. In paragraph 11, A method for decomposing fluorinated gas, wherein the second metal is combined with carbon (C), nitrogen (N) or sulfur (S) of the fluorinated gas.

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