Air separation plant

Abstract

The object of this invention is to provide an air separation device that allows for a small-diameter argon tower and a compact cold box structure without reducing the argon recovery rate. This invention provides an air separation device (100) comprising an argon tower for refining argon from air, the air separation device having a low-pressure tower (600) which is a plate tower, and the argon tower being a regularly packed tower. The regularly packed material filling the regularly packed tower is a structure formed by overlapping and binding corrugated metal sheets (81) processed into corrugated plates with their surfaces aligned with the tower axis of the argon tower, having a specific surface area of ​​750 m². 2 / m 3 In the above, the angle formed by the line connecting the top of the corrugations on the surface of the corrugated plate and the line perpendicular to the tower axis of the argon tower, i.e., the corrugation tilt angle, is less than 40°. In the cross-sectional view of the corrugated plate in the thickness direction, the diameter of the curvature circle at the top of each corrugation is more than 60% of the corrugation crest height, where the corrugation crest height is the distance between the top and bottom of the corrugation.

Description

Technical Field

[0001] This invention relates to an air separation apparatus having an argon tower, and more specifically, to an air separation apparatus for directly obtaining argon without adding hydrogen. Background Technology

[0002] In smaller-scale air separation units that obtain argon without hydrogen addition, plate columns are used for both high-pressure and low-pressure columns, while a combination of plate columns and packed columns is used for the argon column.

[0003] The use of plate columns in argon towers is to reduce pressure by taking advantage of the high pressure loss caused by the plates, and to improve argon recovery by increasing the relative volatility of argon relative to oxygen in the packed tower located downstream.

[0004] Patent documents 1 and 2 disclose air separation devices that use this type of plate tower as an argon tower.

[0005] Figure 6 An example of an air separation apparatus disclosed in Patent Documents 1 and 2 is shown. The air separation apparatus 101 includes an argon tower comprising a high-pressure tower 500, a low-pressure tower 600, a crude argon tower 711, and a deoxygenation tower 721. The high-pressure tower 500 and the low-pressure tower 600 are plate towers. The crude argon tower 711 combines a plate tower and a regularly packed tower (a packed tower filled with a regularly packed material).

[0006] A portion of the compressed and purified feed air is supplied to heat exchanger 201 via pipe 21. In heat exchanger 201, the purified feed air is cooled by heat exchange with nitrogen supplied from the top of low-pressure tower 600 via pipe 2, exhaust gas supplied from heat exchanger 202 via pipe 3, and liquid oxygen supplied from main condenser 300 via pipe 1. Then, it is supplied to the bottom of high-pressure tower 500 via pipe 22. Additionally, another portion of the purified feed air, after being pressurized, is supplied to heat exchanger 201 via pipe 11 and liquefied, then supplied to the bottom of high-pressure tower 500 via pipe 12.

[0007] Air supplied to the bottom of the high-pressure tower 500 via pipe 22 comes into gas-liquid contact with the reflux liquid flowing down inside the high-pressure tower 500. As it rises, the low-boiling-point nitrogen is concentrated, thereby generating nitrogen gas at the top of the tower. Meanwhile, the reflux liquid flowing down inside the high-pressure tower 500, containing liquid air supplied from pipe 12, accumulates high-boiling-point oxygen as it descends, thereby generating oxygen-enriched liquid air at the bottom of the tower. The generated liquid air is extracted from the lower part of the high-pressure tower 500 via pipe 51.

[0008] The nitrogen generated in the high-pressure tower is liquefied in the main condenser 300. A portion of it is supplied to the heat exchanger 202 through pipeline 61 and cooled. After being depressurized through pipeline 62, it is supplied as reflux liquid to the top of the low-pressure tower 600.

[0009] The oxygen-enriched liquid air generated at the bottom of the high-pressure tower 500 is supplied to the heat exchanger 202 via pipe 41 and cooled. After being depressurized via pipe 42, it is introduced into the argon condenser 400, which serves as the top condenser of the deoxygenation tower 721. The introduced oxygen-enriched liquid air evaporates and is then supplied to the low-pressure tower 600. On the other hand, liquid air drawn from below the high-pressure tower 500 via pipe 51 is supplied to the heat exchanger 202 and cooled. After being depressurized via pipe 52, it is supplied to the low-pressure tower 600 as reflux liquid. The reflux liquid supplied to the low-pressure tower 600 undergoes gas-liquid contact with the rising gas inside the tower, concentrating the high-boiling-point oxygen as it flows down, thereby generating liquid oxygen at the bottom of the tower. In addition, the rising gas concentrates the low-boiling-point nitrogen as it rises, thereby generating nitrogen gas at the top of the tower.

[0010] Additionally, argon feed gas with an argon concentration of 5% to 15% (the remaining component is essentially oxygen) is extracted from the middle section of the low-pressure tower 600 via pipeline 31 and supplied to the bottom of the crude argon tower 711. The supplied argon feed gas rises while concentrating the low-boiling-point argon components. It is then introduced from the crude argon tower 711 to the bottom of the deoxidation tower 721 and rises within the deoxidation tower 721. During the rise, oxygen is removed, and at the top of the deoxidation tower 721, the oxygen concentration in the rising gas is 0.1 ppm to 10 ppm. The gas taken from the top of the deoxidation tower 721 is liquefied in the argon condenser 400, a portion of which is obtained as product argon, and the remainder is returned to the deoxidation tower 721 as reflux liquid.

[0011] Patent Document 1: Japanese Patent Application Publication No. 04-222380

[0012] Patent Document 2: Japanese Patent Application Publication No. 04-214174

[0013] As the deoxygenation tower 721, a regular packed tower with low pressure loss is used. A regular packed tower is used in the upper part of the crude argon tower 711, while a plate tower with high pressure loss is used in the lower part. Because a plate tower is used in the lower part of the crude argon tower 711, the pressure loss of the argon feed gas supplied to the bottom of the tower is large; even in a lower plate tower, the pressure will drop. The feed gas supplied to the argon tower rises while its pressure decreases in the plate tower. Then, in the upper part of the crude argon tower 711 (which is a regular packed tower) and in the deoxygenation tower 721, the relative volatility of argon is increased, thereby concentrating argon with good separation efficiency.

[0014] Compared to packed columns, plate columns have a larger diameter to handle the same gas-liquid load, such as... Figure 6As shown, only the lower part of the crude argon column 711 is relatively thick, and the cold box that houses these columns and prevents external heat from entering has the problem of being too large and inappropriate. Summary of the Invention

[0015] The present invention provides an air separation device that allows the argon tower to be made of a small diameter and the cold box to be made of a compact structure without reducing the argon recovery rate.

[0016] To address the aforementioned issues, the present invention provides the following air separation device.

[0017] [1] An air separation device comprising an argon tower for refining argon from air,

[0018] The air separation device has a low-pressure tower.

[0019] The low-pressure tower is a plate tower.

[0020] The argon tower is a regularly packed tower.

[0021] The regular filler in the regular-filled tower is a structure formed by overlapping corrugated metal sheets, processed into corrugated plates, with their surfaces aligned along the tower axis of the argon tower. The specific surface area of ​​the regular filler is 750 m². 2 / m 3 above,

[0022] The angle formed by the line connecting the top of the corrugations on the surface of the corrugated plate and the line perpendicular to the axis of the argon tower, i.e., the corrugation tilt angle, is less than 40°.

[0023] In the cross-sectional view of the corrugated sheet in the thickness direction, the diameter of the curvature circle at the top of each corrugation is more than 60% of the corrugation height, where the corrugation height is the distance between the top and bottom of the corrugation.

[0024] [2] According to the air separation device described in [1], the argon tower is divided into a first tower and a second tower.

[0025] The first column is a crude argon column used to concentrate argon from the argon feed gas from the low-pressure column.

[0026] The second tower is a deoxygenation tower for removing oxygen from the concentrated argon gas obtained from the crude argon tower.

[0027] The air separation device further includes a pipeline for supplying gas from the crude argon tower to the deoxygenation tower.

[0028] The first tower and the second tower are respectively the rule-filled towers.

[0029] [3] According to the air separation device of [2], a pressure reducing valve is provided on the pipeline supplying concentrated argon gas from the crude argon tower to the deoxygenation tower.

[0030] According to the air separation apparatus of the present invention, the argon tower can be made with a small diameter and the cold box can be made with a compact structure without reducing the argon recovery rate.

[0031] Furthermore, since the air separation device of the present invention uses a plate tower as a low-pressure tower, the pressure of the argon feed gas supplied to the argon tower will not drop significantly. Therefore, in the argon condenser, a sufficient temperature difference can be ensured to generate the reflux liquid for the argon tower. Attached Figure Description

[0032] Figure 1 This is a system diagram illustrating an example of the air separation apparatus of the present invention, which uses a crude argon tower and a deoxygenation tower as regular packed towers.

[0033] Figure 2 This is a diagram illustrating an example of a regular packing material used in the argon tower of the air separation apparatus of the present invention.

[0034] Figure 3A This is a diagram showing corrugated plates constituting a regular filler and illustrating the corrugation tilt angle. This regular filler is the filler present in the argon tower of the air separation device of the present invention.

[0035] Figure 3B This is a diagram showing corrugated plates constituting a regular filler and illustrating the corrugation tilt angle. This regular filler is the filler present in the argon tower of the air separation device of the present invention.

[0036] Figure 4 This is a cross-sectional view of the corrugated plate along line A-A' shown in Figure 3, and is a diagram used to illustrate the diameter ratio of the top curvature circle.

[0037] Figure 5 This is a graph showing the oxygen concentration distribution in the argon towers of Example 1 and Comparative Example 1.

[0038] Figure 6 This is a system diagram showing an existing air separation unit with a high-pressure tower, a low-pressure tower, and an argon tower. Detailed Implementation

[0039] Hereinafter, an air separation device according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, for ease of understanding and convenience, the drawings used in the following description sometimes show enlarged feature portions, and the dimensions and proportions of each structural element may not be identical to the actual dimensions.

[0040] Figure 1An air separation device using an argon tower with a regular filling structure is shown.

[0041] Figure 1 The air separation device 100 shown includes an argon tower comprising a high-pressure tower 500, a low-pressure tower 600, a crude argon tower (first tower) 710, and a deoxygenation tower (second tower) 720.

[0042] In the air separation device 100 of this embodiment, a plate tower is used as the low-pressure tower 600.

[0043] In the air separation apparatus 100 of this embodiment, the argon tower is divided into a crude argon tower 710 and a deoxygenation tower 720, thus having two towers. However, the argon tower may also be constructed as a single tower instead of two separate towers. In the case of a single tower, the crude argon tower 710 and the deoxygenation tower 720 are integrated as a single cylinder without being connected by pipes 73 and 74. However, in order to reduce the height of the cold box used to maintain these devices operating at extremely low temperatures, it is preferable to divide the argon tower into two towers.

[0044] In this embodiment, it is preferable that the argon tower does not have a plate tower configuration that would increase the tower diameter. When the argon tower does not have a plate tower configuration, the tower diameter can be reduced.

[0045] Typically, sieve trays are used in plate columns, where gas comes into cross-shaped contact with liquid flowing on the sieve tray in a direction perpendicular to the column axis, separating the low-boiling-point component argon.

[0046] Furthermore, in the air separation apparatus 100 of this embodiment, the crude argon tower 710 and the deoxygenation tower 720 constituting the argon tower are filled with the same regular packing material, but different regular packing materials may also be used. In this case, considering separation performance and pressure loss, a regular packing material is preferred in order to make the argon tower and cold box a compact structure.

[0047] The structure of the air separation device 100 using the argon tower described above will be explained in detail below.

[0048] A portion of the compressed and purified feed air is supplied to heat exchanger 201 via pipe 21. In heat exchanger 201, the purified feed air is cooled by exchanging heat with nitrogen supplied from the top of low-pressure tower 600 via pipe 2, exhaust gas supplied from pipe 3, and liquid oxygen supplied from main condenser 300 via pipe 1. Then, it is supplied to the bottom of high-pressure tower 500 via pipe 22. Additionally, another portion of the purified feed air, after being pressurized, is supplied to heat exchanger 201 via pipe 11 and liquefied, and is supplied to the lower part of high-pressure tower 500 via pipe 12.

[0049] Air supplied to the bottom of the high-pressure tower 500 via pipe 22 comes into gas-liquid contact with the reflux liquid flowing down inside the high-pressure tower 500, accumulating low-boiling-point nitrogen as it rises, thus generating nitrogen gas at the top of the tower. Meanwhile, the reflux liquid flowing down inside the high-pressure tower 500, containing liquid air supplied from pipe 12, accumulates high-boiling-point oxygen as it descends, thus generating oxygen-enriched liquid air at the bottom of the tower. The generated liquid air is then extracted from the bottom of the high-pressure tower 500 via pipe 51.

[0050] The nitrogen generated in the high-pressure tower 500 is liquefied in the main condenser 300. A portion of it is supplied to the heat exchanger 202 through pipeline 61 and cooled. After being depressurized through pipeline 62, it is supplied as reflux liquid to the top of the low-pressure tower 600.

[0051] The oxygen-enriched liquid air generated at the bottom of the high-pressure tower 500 is supplied to the heat exchanger 202 via pipe 41 and cooled. After being depressurized via pipe 42, it is introduced into the argon condenser 400, which serves as the top condenser of the argon tower. The introduced oxygen-enriched liquid air evaporates and is then supplied to the low-pressure tower 600. On the other hand, liquid air drawn from the bottom of the high-pressure tower 500 via pipe 51 is supplied to the heat exchanger 202 and cooled. After being depressurized via pipe 52, it is supplied to the low-pressure tower 600 as reflux liquid. The reflux liquid supplied to the low-pressure tower 600 undergoes gas-liquid contact with the rising gas inside the tower, concentrating the high-boiling-point oxygen as it flows down, thereby generating liquid oxygen at the bottom of the tower. In addition, the rising gas concentrates the low-boiling-point nitrogen as it rises, thereby generating nitrogen gas at the top of the tower.

[0052] Additionally, argon feed gas with an argon concentration of 5% to 15% (the remaining component is essentially oxygen) is extracted from the middle section of the low-pressure tower 600 via pipeline 31 and supplied to the bottom of the crude argon tower 710. The supplied argon feed gas rises while concentrating the low-boiling-point argon components. It is then introduced from the top of the crude argon tower 710 to the bottom of the deoxidation tower 720 and rises there. Oxygen is removed during the ascent, and at the top of the deoxidation tower 720, the oxygen concentration in the rising gas is 0.1 ppm to 10 ppm. The gas taken from the top of the deoxidation tower 720 is liquefied in the argon condenser 400; a portion is obtained as product argon, and the remainder is returned to the deoxidation tower 720 as reflux liquid.

[0053] When the argon column is divided into a crude argon column 710 and a deoxygenation column 720, it is preferable to install a pressure reducing valve 70 on pipeline 73, which is the pipeline that introduces the gas obtained from argon concentration in the crude argon column 710 from the top of the crude argon column 710 to the bottom of the deoxygenation column 720. By installing the pressure reducing valve 70 on pipeline 73, even if the pressure loss in the crude argon column 710 is reduced due to reduced-volume operation, the pressure in the deoxygenation column 720 can be adjusted, thereby increasing the argon recovery rate.

[0054] The following describes the regular packing materials used in the crude argon tower 710 and the deoxygenation tower 720.

[0055] Figure 2 An example of a regular packing material used in the argon tower of the air separation apparatus of the present invention is shown. Figure 3A and Figure 3B This is a diagram showing corrugated plates constituting a regular filler and illustrating the corrugation tilt angle. This regular filler is the filler present in the argon tower of the air separation device of the present invention. Figure 4 This is a cross-sectional view of the corrugated plate along line A-A' shown in Figure 3, which is used to illustrate the diameter ratio of the top curvature circle.

[0056] The rule filler is to combine multiple such as Figure 3A and Figure 3B The structure shown is obtained by stacking corrugated plates 81. The corrugated plates 81 can also be metal sheets with a wave pattern.

[0057] Here, "overlapping" refers to the state in which corrugated plates 81 are bundled together in an alternating manner, with the orientations of their corrugation tilt angles α alternating. Specifically, it refers to the state in which multiple corrugated plates 81 with the same corrugation tilt angle α are alternately overlapped and bundled without overlapping each other. The overlapping and bundled corrugated plates 81 do not necessarily have to be the same size; they can also be overlapping and bundled corrugated plates 81 of different sizes. In the case of a cylindrical argon tower, such as... Figure 2 As shown, multiple corrugated sheets 81 of different sizes can also be overlapped, and a frame can be used to bind the overlapping corrugated sheets 81 into a cylindrical shape. The shape is not limited to a cylindrical shape. It is preferable to overlap multiple corrugated sheets 81 and treat them as a single block.

[0058] Furthermore, there are no particular limitations on the method of binding the corrugated sheets 81. In this embodiment, a metal strip is used as a frame for binding. The material of the corrugated sheets 81 is preferably metal. Among metals, aluminum is preferred.

[0059] The corrugated sheet 81 will be described in detail below.

[0060] like Figure 3A and Figure 3BAs shown, a wave pattern is formed on the surface of the corrugated plate 81, and a through hole 82 is also provided.

[0061] The waveform is formed such that the angle α formed by the line connecting the top of the waveform and the line perpendicular to the axis of the argon tower, i.e., the corrugation tilt angle α, is less than 40°. That is, the line connecting the top of the corrugations set on the corrugated plate 81 forms an angle perpendicular to the axis of the argon tower or tilted at an angle of more than 50°.

[0062] Figure 3A A corrugated plate 81 is shown with a corrugated tilt angle α of less than 40° in the counterclockwise direction relative to a line perpendicular to the axis of the argon tower. Figure 3B A corrugated plate 81 is shown with a corrugated tilt angle α of less than 40° in the clockwise direction relative to a line perpendicular to the axis of the argon tower.

[0063] In the argon column, the descending reflux liquid flows down along the corrugated plates 81, while the rising gas flows between the corrugated plates 81 where the reflux liquid flows, thus achieving gas-liquid contact. The through-holes 82 allow the gas and liquid to move radially along the column, thereby suppressing flow deviation. Here, if the inclination angle α of the corrugations on the corrugated plates 81 is less than 40°, the resistance to the rising gas flow between the corrugated plates 81 in the argon column increases, and the pressure loss is high enough to increase the relative volatility of argon, thus allowing the argon column to be designed with a small diameter without reducing the argon recovery rate.

[0064] Furthermore, in the cross-sectional view along the thickness direction of the corrugated sheet 81, when the distance between the top and bottom of the corrugations is defined as the crest height, the ratio of the diameter of the curvature circle at the crest of each corrugation to the crest height (hereinafter sometimes referred to as the "crown curvature circle diameter ratio") is 60% or more in the cross-sectional view along the thickness direction of the corrugated sheet 81. A crown curvature circle diameter ratio of 100% means that the inclination of the corrugations on the corrugated sheet 81 is zero. Therefore, in order to form a corrugated shape, the crown curvature circle diameter ratio must be less than 100%.

[0065] If the diameter of the top curvature circle is greater than 60%, high separation performance can be obtained even with high pressure loss. Therefore, the argon tower can be set to a small diameter without increasing the height of the argon tower.

[0066] The specific surface area of ​​corrugated sheet 81 is 750 m². 2 / m 3 That's all. If the specific surface area is 750 m²... 2 / m 3 The above can improve the separation efficiency in the argon column. A more preferred value is 920m. 2 / m 3 If the specific surface area of ​​corrugated sheet 81 is 750 m², 2 / m 3In this way, the gas rising in the argon tower comes into full contact with the fluid descending in the argon tower, thus allowing the argon tower to be set to a smaller diameter without reducing the argon recovery rate.

[0067] Furthermore, the specific surface area of ​​the corrugated plate 81 can be adjusted by changing the diameter of each top curvature circle. By setting the diameter of each top curvature circle to 60% or more, the specific surface area of ​​the corrugated plate 81 can be easily set to 750 m². 2 / m 3 above.

[0068] In this embodiment, any corrugated sheet can be used as long as the corrugation tilt angle α and the top curvature circle diameter ratio of the corrugated sheet 81 are within the above range.

[0069] Example

[0070] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0071] Reference Example 1

[0072] Table 1 shows the HETP and pressure loss obtained in argon-oxygen total reflux distillation experiments using a regularly packed column under different gas loads (factor based on empty column velocity: fs). The regularly packed column used regular packing a750_α40D80, with a column diameter of 300 mm, a packing height of 1500 mm, and a specific surface area of ​​750 m² for the regular packing a750_α40D80. 2 / m 3 The corrugation tilt angle α is 40°, and the top curvature circle diameter ratio is 80%. Additionally, Table 1 also shows the comparison filler a750_α45D50 (specific surface area: 750 m²). 2 / m 3 The measurement results are as follows: (correlation tilt angle: 45°, top curvature circle diameter ratio: 50%).

[0073] HETP is the packing height per theoretical plate, calculated by dividing the packing height by the number of theoretical plates based on measured oxygen concentrations at the top and bottom of the column. The values ​​in the table are based on a packing density of fs = 1.7 m / s (kg / m³). 3 ) 0.5 The HETP value at that time is the standardized value of the measured HETP.

[0074] Pressure loss is the pressure difference per unit filling height, which is calculated by dividing the readings from the differential pressure gauges at the top and bottom of the column by the filling height.

[0075] The values ​​in the table are used to compare the filler material's fs = 1.7 m / s (kg / m³). 3 ) 0.5The pressure loss during the time period is the value after standardization of the pressure loss.

[0076] [Table 1]

[0077] Table 1 HETP and pressure loss of regular packing

[0078]

[0079] In the existing argon column, the comparative packing material a750_α45D50 was used. As shown in Table 1, compared to the comparative packing material, it can be seen that higher separation performance can be achieved with higher pressure loss when the packing material is used. Furthermore, it can be seen that with the comparative packing material, increasing the load results in a larger pressure loss without changing the separation performance, and the separation performance cannot be achieved as with the packing material.

[0080] (Example 1)

[0081] To calculate the specific surface area using regular filler a750_α40D80 (specific surface area: 750m²), 2 / m 3 The separation behavior of a regular-filled tower (with a corrugation angle of 40° and a top curvature circle diameter of 80%) was studied using a simulator employed in the design of a regular-filled tower for an air separation device.

[0082] The simulator is used to calculate separation behavior based on heat and mass transfer velocity across the gas-liquid interface. By combining this with experimentally obtained separation performance, it can also be applied to cases where the regular packing material (specific surface area, corrugation tilt angle, and top curvature circle diameter ratio) is modified. Additionally, it incorporates experimentally based formulas for calculating pressure loss. Figure 5 Is Figure 1 Simulation results of the separation behavior of the crude argon column and deoxygenation column using regular packing a750_α40D80 in an air separation device.

[0083] (Comparative Example 1)

[0084] exist Figure 6 In an air separation device, the separation behavior of an argon column consisting of a crude argon column and a deoxygenation column was simulated. The lower part of the crude argon column uses a plate column, while the upper part uses the aforementioned comparative packing material a750_α45D50 (specific surface area: 750 m²). 2 / m 3 (Corrugated inclination angle: 45°, top curvature circle diameter ratio: 50%), this deaerator also uses the comparative packing a750_α45D50. The results are as follows: Figure 5 As shown.

[0085] Figure 5The vertical axis represents the vapor phase oxygen concentration, and the horizontal axis represents the filling height when the filling height of the argon column in Comparative Example 1 is set to 1 (with the top of the column set to 0). Furthermore, for the horizontal axis (filling height) of the plate column, the values ​​obtained by dividing the tray spacing by the tray efficiency are accumulated up to the theoretical number of trays.

[0086] exist Figure 5 In the diagram, the solid line represents the oxygen concentration distribution in the argon tower of Example 1, and the dashed line represents the oxygen concentration distribution in the argon tower of Comparative Example 1.

[0087] like Figure 5 As shown, argon containing 1 ppm oxygen can be obtained in the argon column of Example 1 and the argon column of Comparative Example 1 at approximately the same filling height. This indicates that the argon recovery rate of Example 1 is not reduced compared to Comparative Example 1.

[0088] in addition, Figure 5 The diameter of the crude argon column is also shown (with the diameter of the plate column set to 1). It can be seen that the diameter of the crude argon column in Example 1 can be reduced by more than 25% compared to the diameter of the plate column section in Comparative Example 1. Therefore, the cold box can be designed with a compact structure.

[0089] (Example 2)

[0090] In addition to using Figure 1 The argon tower separation behavior was simulated in the same manner as in Example 1, except for the air separation device shown below. In this air separation device, the argon tower consists of a deoxygenation tower and a crude argon tower, and is filled with a regular packing material a750_α35D80 (specific surface area: 750 m²). 2 / m 3 (Corrugated inclination angle: 35°, top curvature circle diameter ratio: 80%), a pressure reducing valve 70 is installed on the pipe 73 connecting the two towers. The results are shown in Table 2 below.

[0091] (Example 3)

[0092] In addition to using Figure 1 The argon tower separation behavior was simulated in the same manner as in Example 1, except for the air separation device shown below. In this air separation device, the argon tower consists of a deoxygenation tower and a crude argon tower, and is filled with a regular packing material a920_α40D80 (specific surface area: 920 m²). 2 / m 3 (Corrugated inclination angle: 40°, top curvature circle diameter ratio: 80%), a pressure reducing valve 70 is installed on the pipe 73 connecting the two towers. The results are shown in Table 2 below.

[0093] (Example 4)

[0094] In addition to using Figure 1The argon tower separation behavior was simulated in the same manner as in Example 1, except for the air separation device shown below. In this air separation device, the argon tower consists of a deoxygenation tower and a crude argon tower, and the deoxygenation tower is filled with a regular packing material a750_α40D60 (specific surface area: 750 m²). 2 / m 3 (Corrugated inclination angle: 40°, top curvature circle diameter ratio: 60%), the crude argon column is filled with a regular packing material a750_α35D80 (specific surface area: 750 m²). 2 / m 3 (Corrugated inclination angle: 35°, top curvature circle diameter ratio: 80%), a pressure reducing valve 70 is installed on the pipe 73 connecting the two towers. The results are shown in Table 2 below.

[0095] (Example 5)

[0096] In addition to using Figure 1 The argon tower separation behavior was simulated in the same manner as in Example 1, except for the air separation device shown below. In this air separation device, the argon tower consists of a deoxygenation tower and a crude argon tower, and the deoxygenation tower is filled with a regular packing material a750_α40D70 (specific surface area: 750 m²). 2 / m 3 (Corrugated tilt angle: 40°, top curvature circle diameter: 70%), the crude argon column is filled with a regular packing material a920_α40D80 (specific surface area: 920 m²). 2 / m 3 (Corrugated inclination angle: 40°, top curvature circle diameter ratio: 80%), a pressure reducing valve 70 is installed on the pipe 73 connecting the two towers. The results are shown in Table 2 below.

[0097] Additionally, the results of Example 1 are also shown in Table 2 below.

[0098] [Table 2]

[0099] Table 2 Argon Towers in Examples

[0100]

[0101] *Includes pressure rise loss

[0102] As shown in Table 2 above, it can be seen that in any embodiment, compared with Comparative Example 1, argon containing 1 ppm oxygen can be obtained when the filling height is approximately the same or lower.

[0103] It is also known that Examples 2, 3, 4 and 5 can achieve the same degree of miniaturization of the argon tower as Example 1.

[0104] Furthermore, it is known that the larger the specific surface area and the smaller the corrugation tilt angle α, the lower the filling height. However, due to the increased pressure loss, the temperature difference of the argon condenser decreases, and the heat transfer surface increases. Therefore, considering the equipment layout within the cold box, a regular filling material is selected to make the cold box compact.

[0105] Industrial availability

[0106] According to the air separation apparatus of the present invention, the argon tower can be made with a small diameter and the cold box can be made with a compact structure without reducing the argon recovery rate. The air separation apparatus of the present invention is useful as a smaller-scale air separation apparatus.

[0107] Explanation of reference numerals in the attached figures

[0108] Pipelines 1, 2, 3, 11, 12, 21, 22, 31, 51, 61, 73

[0109] 70 Pressure Regulator

[0110] 81 Corrugated sheet

[0111] 82 Through Holes

[0112] 100, 101 Air Separation Devices

[0113] 201. Heat Exchanger

[0114] 300 Main Condenser

[0115] 400 (Argon tower) Top condenser

[0116] 500 High-voltage tower

[0117] 600 Low-pressure tower

[0118] 710 and 711 crude argon towers

[0119] 720 and 721 deoxygenation towers

Claims

1. An air separation apparatus comprising an argon column for refining argon from air, The air separation device has a low-pressure tower. The low-pressure tower is a plate tower. The argon tower is a regularly packed tower. The regular filler in the regular-filled tower is a structure formed by overlapping and binding corrugated metal sheets, processed into corrugated plates, with the surfaces of the corrugated plates along the tower axis of the argon tower. The specific surface area of ​​the regular filler is 750 m². 2 / m 3 above, The angle formed by the line connecting the top of the corrugations on the surface of the corrugated plate and the line perpendicular to the axis of the argon tower, i.e., the corrugation tilt angle, is less than 40°. In the cross-sectional view of the corrugated sheet in the thickness direction, the diameter of the curvature circle at the top of each corrugation is more than 60% of the corrugation height, where the corrugation height is the distance between the top and bottom of the corrugation.

2. The air separation device according to claim 1, wherein, The argon tower is divided into a first tower and a second tower. The first column is a crude argon column used to concentrate argon from the argon feed gas from the low-pressure column. The second tower is a deoxygenation tower for removing oxygen from the concentrated argon gas obtained from the crude argon tower. The air separation device further includes a gas supply line that supplies gas from the crude argon tower to the deoxygenation tower. The first tower and the second tower are respectively the rule-filled towers.

3. The air separation device according to claim 2, wherein, A pressure reducing valve is installed on the gas supply pipeline that supplies concentrated argon gas from the crude argon tower to the deoxygenation tower.

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