Sulfur dioxide mixture filled container and sulfur dioxide composition

Abstract

This sulfur dioxide mixture-filled container is provided with: a sealed container; and a sulfur dioxide mixture which is filled in the sealed container and contains at least sulfur dioxide and gas-phase moisture. In the container filled with the sulfur dioxide mixture, the sealed container comprises a cylindrical body part, the cylindrical body part is provided with a metal layer having an inner surface in contact with the sulfur dioxide mixture, and the maximum height of surface roughness of the inner surface of the metal layer of the cylindrical body part is 38 [mu] m or less.

Description

Technical Field

[0001] The invention relates to a sulfur dioxide mixture filling container and a sulfur dioxide composition. Background Art

[0002] Containers used for storage and transportation of liquefied gas and compressed gas are usually made of metals such as steel and alloys, and are used for gas storage and supply in various industries. In recent years, even though the demand for sulfur dioxide in liquefied gas has increased in semiconductor manufacturing processes, sulfur dioxide is corrosive to metals and corrodes closed containers. Therefore, this property may cause the problem of trace metal impurities in the gas, which may become a problem in semiconductor manufacturing processes. As a solution to this problem, there are examples of imparting corrosion resistance to closed containers and piping by limiting the impurity concentration of the sulfur dioxide filled. For example, in the following patent document 1, a scheme is proposed to suppress metal corrosion by setting the moisture concentration of the gas phase to a sulfur dioxide mixture of 0.005 mol ppm or more and less than 5000 mol ppm.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2021-182045 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] However, the sulfur dioxide mixture described in Patent Document 1 has the following problems.

[0008] That is, the sulfur dioxide mixture described in Patent Document 1 is used in a sealed container made of commonly known stainless steel, and the sulfur dioxide has corrosion resistance, and the use is limited to the metal material of the sealed container. In other words, when the sulfur dioxide mixture is used, if the sealed container is made of a metal material other than stainless steel, the sealed container may corrode.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a sulfur dioxide mixture-filled container and a sulfur dioxide composition capable of suppressing corrosion of the sealed container caused by the sulfur dioxide mixture even when the metal material of the sealed container is set to a material other than stainless steel.

[0010] Means for solving technical problems

[0011] The present inventors have conducted intensive studies to solve the above problems and have found that the above problems can be solved by setting the maximum height of the surface roughness of the inner surface of the cylindrical body of the closed container storing the sulfur dioxide mixture to a specific range.

[0012] That is, one aspect of the present invention provides a sulfur dioxide mixture filled container, which comprises: a metal sealed container; and a sulfur dioxide mixture, which is filled in the above-mentioned sealed container and contains at least sulfur dioxide and water in the gas phase, and the above-mentioned sealed container includes a cylindrical body, and the maximum height of the surface roughness of the inner surface of the above-mentioned cylindrical body is less than 38μm.

[0013] In addition, the cylindrical body portion in the present invention is defined in accordance with JISB 0190:2010.

[0014] According to the above sulfur dioxide mixture filled container, even when the metal material of the sealed container is made of a material other than stainless steel, corrosion of the sealed container caused by the sulfur dioxide mixture can be suppressed.

[0015] According to the present invention, the reason why the corrosion of the sealed container caused by the sulfur dioxide mixture can be suppressed even when the metal material of the sealed container is made of a material other than stainless steel is not clear, but the present inventors presume that this is due to the following reason.

[0016] That is, by setting the maximum height of the surface roughness of the inner surface of the cylindrical body of the sealed container to 38 μm or less, the water in the sulfur dioxide mixture becomes less likely to be captured by the concave portion of the inner surface of the cylindrical body, and even if captured, it becomes easy to escape. Therefore, the amount of sulfur dioxide dissolved in the water is reduced, and the generation of corrosive substances caused by the reaction of water and sulfur dioxide gas is suppressed. In this way, the inventors of the present invention speculate that the corrosion of the sealed container may be suppressed when the metal material of the sealed container is set to a material other than stainless steel.

[0017] Furthermore, another aspect of the present invention provides a sulfur dioxide composition obtained by taking out the above sulfur dioxide mixture-filled container.

[0018] According to the sulfur dioxide mixture filled in the above-mentioned sealed container, the corrosion of the metal sealed container including a cylindrical body and the maximum height of the surface roughness of the inner surface of the cylindrical body being 38 μm or less can be suppressed. Therefore, when the metal material of the sealed container is set to a material other than stainless steel, the corrosion of the sealed container can also be suppressed. Therefore, by suppressing the corrosion of the sealed container, it is possible to suppress the mixing of metal components into the sulfur dioxide mixture. Therefore, the sulfur dioxide composition obtained by taking out from the sulfur dioxide mixture filled container is useful in semiconductor manufacturing processes and the like that require a small content of metal components.

[0019] In the sulfur dioxide mixture-filled container, the concentration of the water in the sulfur dioxide mixture is preferably 1000 mol ppm or less.

[0020] In the sulfur dioxide mixture-filled container, the maximum height of the surface roughness of the inner surface of the cylindrical body is preferably 23 μm or less.

[0021] In the sulfur dioxide mixture-filled container, the maximum height of the surface roughness of the inner surface of the cylindrical body is more preferably 6 μm or less.

[0022] In the sulfur dioxide mixture-filled container, it is further preferred that the maximum height of the surface roughness of the inner surface of the cylindrical body be 1 μm or less.

[0023] In the above-mentioned sulfur dioxide mixture filled container, the metal constituting the above-mentioned closed container may include alloy steel.

[0024] The above alloy steel can be manganese steel or chrome-molybdenum steel.

[0025] Effects of the Invention

[0026] According to the present invention, there are provided a sulfur dioxide mixture-filled container and a sulfur dioxide composition capable of suppressing corrosion of the sealed container caused by the sulfur dioxide mixture even when the metal material of the sealed container is made of a material other than stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a partial cross-sectional view schematically showing one embodiment of a sulfur dioxide mixture filling container according to the present invention.

[0028] Figure 2 This is a flow chart showing an example of a corrosion resistance test apparatus used in the experimental examples.

[0029] Figure 3 It is a graph showing the relationship between the average S (sulfur) concentration at a depth of 100 to 200 nm (in terms of SiO2 thermal oxide film conversion) from the surface of the test pieces in Experimental Examples 1 to 16 and the maximum height Rz of the surface roughness. DETAILED DESCRIPTION

[0030] Hereinafter, an embodiment of the sulfur dioxide mixture filling container of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the accompanying drawings, the same or corresponding parts are marked with the same reference numerals, and repeated descriptions are omitted. In addition, the dimensional ratios of the accompanying drawings are not limited to the ratios shown in the drawings.

[0031] Figure 1 FIG. 1 is a partial cross-sectional view schematically showing an embodiment of a sulfur dioxide mixture filling container according to the present invention. Figure 1 As shown, the sulfur dioxide mixture filling container 100 includes: a metal sealed container 10; and a sulfur dioxide mixture 20 filled in the sealed container 10 and containing sulfur dioxide and water in a gas phase.

[0032] The sealed container 10 may include a cylindrical body portion 11. Furthermore, the maximum height Rz of the surface roughness in the inner surface 10a of the cylindrical body portion 11 is 38 μm or less.

[0033] According to the sulfur dioxide mixture-filled container 100, even when the metal material of the sealed container 10 is made of a material other than stainless steel, corrosion of the sealed container 10 caused by the sulfur dioxide mixture can be suppressed.

[0034] Hereinafter, the sealed container 10 and the sulfur dioxide mixture 20 will be described in more detail.

[0035] <Sealed container>

[0036] The sealed container 10 includes a cylindrical body 11. Specifically, Figure 1 As shown, the closed container 10 further comprises: a bottom 12, which is arranged at the lower end of the cylindrical body 11; a gas discharge portion 13, which is arranged at the upper end side of the cylindrical body 11 and is provided with a valve for filling or discharging the sulfur dioxide mixture 20; and a shoulder 14, which connects the gas discharge portion 13 and the cylindrical body 11.

[0037] The sealed container 10 may be made of metal, and may be composed of a single metal layer or a laminate of two or more metal layers.

[0038] The maximum height Rz of the surface roughness in the inner surface 10a of the cylindrical body 11 may be 38 μm or less. From the viewpoint of further suppressing the corrosion of the closed container 10 caused by the sulfur dioxide mixture 20, the maximum height Rz of the surface roughness in the inner surface 10a of the cylindrical body 11 is preferably 23 μm or less, more preferably 6 μm or less, and further preferably 1 μm or less.

[0039] The maximum height Rz of the surface roughness of the inner surface of the portion other than the cylindrical portion 11 (eg, the bottom portion 12, the gas discharge portion 13, and the shoulder portion 14) is not particularly limited and may be 38 μm or less or greater.

[0040] The maximum height Rz of the surface roughness of the inner surface 10a of the cylindrical body 11 can be achieved, for example, by grinding the inner surface of the unground container. As the grinding method, for example, physical grinding methods such as sandblasting, polishing, and centrifugal drum grinding, chemical grinding methods based on chemical treatment, and electrolytic grinding methods in which electric current is applied to the electrolytic grinding solution for grinding can be cited. The grinding method is not particularly limited to the above-mentioned grinding methods.

[0041] The maximum height Rz of the surface roughness on the inner surface 10a of the cylindrical body portion 11 in the present invention can be measured in accordance with JIS B 0633:2001 and JIS B 0651:2001.

[0042] Specifically, when measuring the maximum height Rz of the surface roughness, a surface roughness measuring instrument sold by a measuring instrument manufacturer can be used. Examples of such a surface roughness measuring instrument include a surface roughness measuring instrument manufactured by Mitutoyo Corporation.

[0043] The metal constituting the sealed container 10 is not particularly limited, and examples thereof include manganese steel, stainless steel, alloy steel such as chrome-molybdenum steel, carbon steel, and aluminum alloy.

[0044] Among them, alloy steel is preferred. In this case, the sulfur dioxide mixture filled container 100 is advantageous in terms of mechanical properties compared to the case where a metal other than alloy steel is used in the sealed container 10. Among alloy steels, manganese steel or chrome-molybdenum steel is also preferred. In this case, the sulfur dioxide mixture filled container 100 is advantageous in terms of cost compared to the case where an alloy steel other than manganese steel or chrome-molybdenum steel is used in the sealed container 10.

[0045] <Sulfur dioxide mixture>

[0046] The sulfur dioxide mixture 20 includes sulfur dioxide and water in a gas phase.

[0047] The water concentration of the gas phase in the sulfur dioxide mixture 20 is not particularly limited, but is preferably 1000 mol ppm or less. Here, the water concentration of the gas phase in the sulfur dioxide mixture 20 is a value measured by a phosphorus pentoxide dew point meter or a cavity ring-down spectroscopy (CRDS). Here, the measurement is performed under the conditions of 20 to 25°C (40°C for the pipe for ventilating the sulfur dioxide mixture) and atmospheric pressure.

[0048] The water concentration of the gas phase in the sulfur dioxide mixture 20 is, for example, 400 mol ppm or less, 100 mol ppm or less, 10 mol ppm or less, or 1 mol ppm or less.

[0049] Here, in particular, when the maximum height Rz of the surface roughness is 23 μm or less, corrosion of the closed container 10 caused by the sulfur dioxide mixture can be effectively suppressed.

[0050] Additionally, the water concentration in the gas phase of the sulfur dioxide mixture 20 may be greater than 400 mol ppm.

[0051] In this case, since the range of water concentration is widened, the process margin in the equipment (water removal equipment) for purifying the sulfur dioxide mixture is widened. Therefore, from the viewpoint of process control in the equipment for producing the sulfur dioxide mixture, it is advantageous that the water concentration of the gas phase in the sulfur dioxide mixture 20 is higher than 400 mol ppm. Furthermore, if the water concentration of the gas phase in the sulfur dioxide mixture 20 is set to higher than 400 mol ppm, the equipment (water removal equipment) for purifying the sulfur dioxide mixture itself may be unnecessary.

[0052] Sulfur dioxide may be a liquefied gas or a non-liquefied gas, but is usually a liquefied gas.

[0053] The method for filling the sulfur dioxide mixture 20 is not particularly limited. When water remains in the sealed container 10, the water concentration in the filled sulfur dioxide mixture 20 increases. Therefore, the amount of residual water in the sealed container 10 may be reduced to 1 mol ppm or less by previously ventilating the sealed container 10 with a dry inert gas or performing a heating and decompression treatment on the sealed container 10.

[0054] <Sulfur dioxide composition>

[0055] The sulfur dioxide composition of the present invention is a composition taken out from the sulfur dioxide mixture filling container 100 .

[0056] According to the sulfur dioxide mixture filled in the sealed container 10, the corrosion of the metal sealed container 10 including the cylindrical body 11 and the maximum height of the surface roughness of the inner surface 10a of the cylindrical body 11 being 38 μm or less can be suppressed. Therefore, even when the metal material of the sealed container 10 is a material other than stainless steel, the corrosion of the sealed container 10 can be suppressed. Therefore, by suppressing the corrosion of the sealed container 10, it is possible to suppress the mixing of metal components into the sulfur dioxide mixture. Therefore, the sulfur dioxide composition obtained by taking out from the sulfur dioxide mixture filled container 100 is useful in semiconductor manufacturing processes and the like which require a small content of metal components.

[0057] Experimental example

[0058] Hereinafter, experimental examples will be described.

[0059] [Test piece]

[0060] As test pieces, manganese steel (150M36-S) in the shape of a cube (10mm×50mm×6mm) with a maximum surface roughness height Rz of 1μm, manganese steel (150M36-S) in the shape of a cube (10mm×50mm×6mm) with a maximum surface roughness height Rz of 20μm, manganese steel (150M36-S) in the shape of a cube (10mm×50mm×6mm) with a maximum surface roughness height Rz of 35μm, manganese steel (150M36-S) in the shape of a cube (10mm×50mm×6mm) with a maximum surface roughness height Rz of 40μm, The maximum height Rz of the surface roughness of the manganese steel (150M36-S) in a cubic shape (10mm×50mm×6mm) of 145μm, the maximum height Rz of the surface roughness of the chromium-molybdenum steel (SAE4130-S) in a cubic shape (20mm×50mm×6mm) of 2μm, the maximum height Rz of the surface roughness of the chromium-molybdenum steel (SAE4130-S) in a cubic shape (20mm×50mm×6mm) of 45μm, and the maximum height Rz of the surface roughness of the chromium-molybdenum steel (SAE4130-S) in a cubic shape (20mm×50mm×6mm) of 125μm. The maximum height Rz of the surface roughness of the test piece was measured using a contact type surface roughness measuring instrument in accordance with JISB 0633:2001 and JISB 0651:2001. As a contact type surface roughness measuring instrument, "SJ-210" manufactured by Mitutoyo Corporation was used for test pieces with maximum height Rz of 1μm, 2μm, 20μm, 35μm, 40μm, and 45μm. As a contact type surface roughness measuring instrument, "SJ-412" manufactured by Mitutoyo Corporation was used for test pieces with maximum height Rz of 125μm and 145μm. In addition, the test piece was used instead of the closed container in order to examine the effect of the maximum height value of the surface roughness of the inner surface of the cylindrical body of the closed container.

[0061] [Experimental Example 1]

[0062] A manganese steel test piece having a maximum surface roughness height Rz of 1 μm was hung on a hook covered with Teflon (registered trademark) and placed on a Figure 2 The storage container 3 was sealed in the SUS304 storage container 3 in the corrosion resistance test apparatus A. Then, nitrogen gas was ventilated to the storage container 3 at 2 L / min for more than 12 hours to remove moisture inside the storage container 3.

[0063] Next, the sulfur dioxide mixed gas raw material 1 containing sulfur dioxide having a water concentration of 1 mol ppm in the gas phase was aerated at 2 L / min for more than 30 minutes into the storage container 3 as the sulfur dioxide mixed gas. At this time, the flow rate of the sulfur dioxide mixed gas was adjusted by the flow rate regulator 2. In addition, the water concentration of the gas phase of the sulfur dioxide mixed gas discharged from the storage container 3 was measured by the moisture meter 4, and it was confirmed that the water concentration of the gas phase was 1 mol ppm.

[0064] Next, the storage container 3 was sealed so that the internal pressure became 0.02 MPaG, and the storage container 3 was filled with sulfur dioxide mixed gas.

[0065] After the sulfur dioxide mixed gas was stored at room temperature (25°C) for about 30 days, the storage container 3 was fully replaced with nitrogen. After that, the storage container 3 was opened and the test piece was taken out. The surface of the test piece was sputtered and a hole was opened, and the S (sulfur) concentration along the depth direction from the surface of the test piece was measured by XPS (X-ray photoelectron spectroscopy). The target elements were set to C, O, S, Mn, and Fe. In addition, the depth of the SiO2 thermal oxide film conversion is specifically expressed as the distance along the depth direction when the SiO2 thermal oxide film is measured under the same conditions.

[0066] Furthermore, based on the measurement results of the S (sulfur) concentration, the average S (sulfur) concentration from the surface to a depth of 100 to 200 nm (converted to SiO2 thermal oxidation film) of the test piece was calculated. The results are shown in Table 1. Here, the average S (sulfur) concentration becomes an indicator of the amount of corrosive substances generated by the reaction of water and sulfur dioxide gas. The lower the average S (sulfur) concentration, the less the amount of corrosive substances generated, which means that the corrosion of the test piece is suppressed.

[0067] Furthermore, the degree of suppression of corrosion of the test piece by the sulfur dioxide mixture was evaluated based on the following evaluation criteria with respect to the average S (sulfur) concentration calculated as described above.

[0068] <Evaluation Criteria>

[0069] ○: The average sulfur concentration from the surface of the test piece to a depth of 100 to 200 nm (converted to SiO2 thermal oxide film) is 0.4 atomic % or less

[0070] ×: The average sulfur concentration of the test piece from the surface to a depth of 100 to 200 nm (converted to SiO2 thermal oxide film) is greater than 0.4 atomic %

[0071] [Experimental Examples 2 to 16]

[0072] As the test piece, a manganese steel test piece or a chrome-molybdenum steel test piece whose maximum surface roughness height Rz is the value shown in Table 1 is used, and as the sulfur dioxide mixed gas raw material 1, the water concentration of the gas phase is the value shown in Table 1, and the sulfur dioxide mixed gas raw material 1 containing sulfur dioxide is used. Except for this, the storage container 3 is filled with the sulfur dioxide mixed gas in the same manner as Experimental Example 1.

[0073] After the sulfur dioxide mixed gas was stored in the same manner as in Experimental Example 1, the inside of the storage container 3 was fully replaced with nitrogen. After that, the storage container 3 was opened and the test piece was taken out, and the S (sulfur) concentration in the depth direction from the surface of the test piece was measured by XPS analysis in the same manner as in Experimental Example 1. In addition, based on the measurement results of the S (sulfur) concentration, the average S (sulfur) concentration from the surface of the test piece to a depth of 100 to 200 nm (SiO2 thermal oxidation film conversion) was calculated in the same manner as in Experimental Example 1. The results are shown in Table 1.

[0074] Furthermore, the degree of suppression of corrosion of the test piece by the sulfur dioxide mixture was evaluated based on the above-mentioned evaluation criteria for the average S (sulfur) concentration calculated as described above.

[0075] [Table 1]

[0076]

[0077] Based on the results shown in Table 1, the maximum height Rz of the surface roughness of the test piece is plotted, and the results of the average S (sulfur) concentration at a depth of 100 to 200 nm (SiO2 thermal oxide film conversion) from the surface of the test piece by XPS analysis are shown in Figure 3 In. Figure 3 In the figure, the horizontal axis is the maximum height Rz of the surface roughness of the test piece, and the vertical axis is the average S (sulfur) concentration from the surface to a depth of 100 to 200 nm (converted to SiO2 thermal oxide film) of the test piece. Figure 3 In the table, “H2O” indicates the water concentration in the gas phase, and “ppm” indicates “molar ppm”.

[0078] Table 1 and Figure 3 The test results of the test piece shown are also applicable to closed containers made of non-stainless steel other than manganese steel and chrome-molybdenum steel. That is, it is considered that even if the metal material of the closed container is a material other than stainless steel, when the maximum height Rz of the surface roughness of the inner surface of the cylindrical body is 38 μm or less, the corrosion of the closed container caused by the sulfur dioxide mixed gas can be suppressed regardless of the water concentration in the gas phase.

[0079] In addition, the outline of the present invention is as follows.

[0080] [1] A sulfur dioxide mixture filling container comprising:

[0081] Metal sealed containers; and

[0082] The sulfur dioxide mixture is filled in the sealed container and contains at least sulfur dioxide and water in gas phase.

[0083] The sealed container comprises a cylindrical body,

[0084] The maximum height of the surface roughness of the inner surface of the cylindrical body is 38 μm or less.

[0085] [2] The sulfur dioxide mixture filled container according to [1], wherein:

[0086] The maximum height of the surface roughness of the inner surface of the cylindrical body is 23 μm or less.

[0087] [3] The sulfur dioxide mixture filled container according to [2], wherein:

[0088] The maximum height of the surface roughness of the inner surface of the cylindrical body is 6 μm or less.

[0089] [4] The sulfur dioxide mixture filled container according to any one of [1] to [3], wherein

[0090] The concentration of the water in the sulfur dioxide mixture is 1000 mol ppm or less.

[0091] [5] The sulfur dioxide mixture filled container according to any one of [1] to [4], wherein

[0092] The metal constituting the closed container includes alloy steel.

[0093] [6] The sulfur dioxide mixture filled container according to [5], wherein:

[0094] The alloy steel is manganese steel or chromium-molybdenum steel.

[0095] [7] A sulfur dioxide composition obtained by taking out the sulfur dioxide mixture-filled container according to any one of [1] to [6].

[0096] Description of Reference Numerals

[0097] A-corrosion resistance test device, 1-sulfur dioxide mixed gas raw material, 2-flow regulator, 3-storage container, 4-moisture meter, 10-sealed container, 10a-inner surface, 11-cylindrical body, 12-bottom, 13-gas discharge part, 14-shoulder, 20-sulfur dioxide mixture, 100-sulfur dioxide mixture filling container.

Claims

1. A sulfur dioxide mixture filling container, comprising: Metal sealed containers; and The sulfur dioxide mixture is filled in the sealed container and contains at least sulfur dioxide and water in gas phase. The sealed container comprises a cylindrical body, The maximum height of the surface roughness of the inner surface of the cylindrical body is 38 μm or less.

2. The sulfur dioxide mixture filling container according to claim 1, wherein: The maximum height of the surface roughness of the inner surface of the cylindrical body is 23 μm or less.

3. The sulfur dioxide mixture filling container according to claim 2, wherein: The maximum height of the surface roughness of the inner surface of the cylindrical body is 6 μm or less.

4. The sulfur dioxide mixture filled container according to any one of claims 1 to 3, wherein: The concentration of the water in the sulfur dioxide mixture is 1000 mol ppm or less.

5. The sulfur dioxide mixture filled container according to any one of claims 1 to 3, wherein: The metal constituting the closed container includes alloy steel.

6. The sulfur dioxide mixture filling container according to claim 5, wherein: The alloy steel is manganese steel or chromium-molybdenum steel.

7. A sulfur dioxide composition obtained by taking out the sulfur dioxide mixture filled container according to claim 1.

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