Ozone supply system and ozone supply method

Abstract

This ozone supply system comprises: an adsorption tower (A, B) which contains an adsorbent that adsorbs ozone generated by an ozone generator (3) from oxygen supplied from an oxygen source (2), and in which an adsorption step for causing the adsorbent to adsorb the ozone and a desorption step for desorbing the ozone from the adsorbent are alternately repeated; a circulation path (120) through which oxygen gas not having been adsorbed onto the adsorbent in the adsorption step is discharged from the adsorption tower (A, B) and circulated to the ozone generator (3); a first supply part (4) for a first carrier gas; a carrier gas introduction path (103) for introducing, in the desorption step, the first carrier gas from the first supply part (4) into the adsorption tower (A, B); a carrier gas discharge path (104) for discharging, in the desorption step, the ozone accompanied by the first carrier gas to the outside of the adsorption tower (A, B); and a depressurization part (5) for depressurizing, in the desorption step, the interior of the adsorption tower (A, B) until the interior is lower than the atmospheric pressure.

Description

Technical Field

[0001] This application relates to an ozone supply system and an ozone supply method.

Background Art

[0002] Conventional ozone supply systems include a high-purity oxygen gas supply source that supplies high-purity oxygen gas as an ozone raw material, an ozone generator that generates ozone using the high-purity oxygen gas supplied from the high-purity oxygen gas supply source as a raw material, an adsorption cylinder filled with an adsorbent that preferentially adsorbs ozone, which alternately performs operations of adsorbing the ozone generated by the ozone generator in a relatively low-temperature adsorption process and desorbing it in a relatively high-temperature desorption process, an oxygen circulation path that circulates and mixes the oxygen gas derived from the adsorption cylinder without being adsorbed by the adsorbent in the adsorption process with the high-purity oxygen gas, a scavenging gas introduction path that introduces a scavenging gas for导出 the ozone desorbed from the adsorbent in the desorption process from the adsorption cylinder, an ozone导出 path that导出 the ozone-accompanied scavenging gas from the adsorption cylinder in the desorption process, an ozone supply path that supplies the ozone-accompanied scavenging gas导出 to the ozone导出 path as product ozone to an ozone consumption destination, and a pump that sucks the gas in the adsorption cylinder, boosts the pressure, and introduces and mixes it into the product ozone (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional ozone supply systems and methods use low-concentration oxygen gas for purging to reduce oxygen consumption. However, nitrogen gas introduced during desorption remains in the adsorption tower, leading to a high nitrogen concentration in the tower during the transition from ozone desorption to adsorption. This results in decreased ozone generation efficiency and the generation of nitrogen oxides, which cause corrosion of pathways and other components.

[0005] This application discloses a technology for solving the above-mentioned problems, and aims to provide an ozone supply system and ozone supply method that can suppress the rise in nitrogen concentration in an adsorption tower. [Means for solving the problem]

[0006] The ozone supply system disclosed herein is An ozone generator that produces ozone from oxygen supplied from an oxygen source, An adsorption tower houses an adsorbent material for adsorbing ozone generated by the ozone generator, and alternately repeats an adsorption step of adsorbing ozone onto the adsorbent material and a desorption step of desorbing ozone from the adsorbent material. In the adsorption process, a circulation path is provided for circulating oxygen that was not adsorbed by the adsorbent from the adsorption tower to the ozone generator. The first supply unit of the first carrier gas, In the desorption process, a carrier gas introduction path is provided for introducing the first carrier gas from the first supply unit into the adsorption tower, In the desorption process, a carrier gas outlet path is provided for releasing the ozone entrained in the first carrier gas to the outside of the adsorption tower. In the desorption process, a depressurization section is used to reduce the pressure inside the adsorption tower until it becomes lower than atmospheric pressure. and, The system includes a second supply unit for a second carrier gas having a nitrogen concentration lower than that of the first carrier gas, The second supply unit is connected to the carrier gas introduction path via a carrier gas switching valve that switches the supply of the first carrier gas and the second carrier gas to the adsorption tower. The carrier gas discharge path discharges the ozone entrained in the second carrier gas during the desorption process to the outside of the adsorption tower. so ru. Ma Furthermore, the ozone supply method disclosed in this application is The adsorption process involves adsorbing the generated ozone onto an adsorbent stored in an adsorption tower, simultaneously releasing the oxygen that was not adsorbed by the adsorbent from the adsorption tower, reintroducing it as a raw material gas into an ozone generator to regenerate ozone, and supplying it back to the adsorption tower. After the adsorption process is completed, a first desorption process is performed in which a first carrier gas is introduced into the adsorption tower, the ozone adsorbed on the adsorbent is desorbed along with the first carrier gas, and then discharged outside the adsorption tower. The system includes a second desorption step in which, after stopping the introduction of the first carrier gas, a second carrier gas with a nitrogen concentration lower than that of the first carrier gas is introduced to desorb the ozone adsorbed on the adsorbent and discharge it outside the adsorption tower, and the first carrier gas remaining in the adsorption tower is replaced with the second carrier gas. [Effects of the Invention]

[0007] The ozone supply system and ozone supply method disclosed herein can suppress the rise in nitrogen concentration in the adsorption tower. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing the configuration of the ozone supply system according to Embodiment 1. [Figure 2] Figure 1 is a flowchart showing the process of supplying ozone using the ozone supply system. [Figure 3] This is a block diagram showing the configuration of the ozone supply system according to Embodiment 2. [Figure 4] Figure 3 is a flowchart showing the process of ozone supply using the ozone supply system. [Figure 5] Figure 3 is a flowchart showing the process of another ozone supply method using the ozone supply system shown. [Modes for carrying out the invention]

[0009] Embodiment 1. Figure 1 is a block diagram showing the configuration of the ozone supply system according to Embodiment 1. Figure 2 is a flow diagram showing the steps of the ozone supply method using the ozone supply system shown in Figure 1. In Figure 1, the ozone supply system 1 comprises an adsorption tower A and an adsorption tower B, an ozone generator 3 connected to both adsorption tower A and adsorption tower B, an ozone introduction path 101, a circulation path 120, a first carrier gas introduction path 103, a carrier gas outlet path 104, a first supply unit 4, and a pressure reduction unit 5.

[0010] Adsorption towers A and B contain adsorbents that adsorb ozone. The ozone supply system 1 alternately switches between an adsorption process in adsorption towers A and B, in which ozone is adsorbed onto the adsorbents, and a desorption process in which ozone is desorbed from the adsorbents after adsorption. The ozone generator 3 introduces oxygen from an oxygen source 2 via a buffer tank 122 (described later), generates ozone, and supplies it to adsorption tower A or adsorption tower B in the adsorption process via an ozone introduction path 101. The circulation path 120 includes a circulation blower 121 for circulating oxygen gas and a buffer tank 122 capable of temporarily storing the circulating oxygen gas, which is drawn out from adsorption tower A or adsorption tower B in the adsorption process and circulated back into the ozone generator 3 for reuse as a raw material gas.

[0011] The first supply unit 4 supplies a first carrier gas to adsorb ozone adsorbed on the adsorbent material to adsorption tower A or adsorption tower B in the desorption process via the first carrier gas introduction path 103. Dry air is used as the first carrier gas. The carrier gas outlet path 104 leads the ozone entrained in the first carrier gas from adsorption tower A or adsorption tower B in the desorption process to the depressurization unit 5.

[0012] The decompression unit 5 decompresses the inside of the adsorption tower A or the adsorption tower B in the desorption process via the carrier gas outlet path 104 until the pressure becomes lower than the atmospheric pressure. The decompression unit 5 is constituted by, for example, a vacuum pump or the like. And, switching valves 11, 12, 13, 14, 15, 16, 17, 18 that open and close in a predetermined procedure when switching the respective processes of the adsorption towers A and B are installed in these respective paths 101, 120, 103, 104.

[0013] Next, the ozone supply method of the ozone supply system of the first embodiment configured as described above will be described. Here, the description will be centered around the adsorption tower A. Naturally, when the adsorption process is being carried out in the adsorption tower A, the desorption process is being carried out in the adsorption tower B. Also, when the desorption process is being carried out in the adsorption tower A, the adsorption process is being carried out in the adsorption tower B. Therefore, since these matters are the same in the following embodiments, the description thereof will be omitted as appropriate.

[0014] First, the ozone generator 3 introduces oxygen from the oxygen source 2, generates ozone, and introduces the ozone into the adsorption tower A in the adsorption process via the ozone introduction path 101. Next, the introduced ozone is adsorbed by the adsorbent in the adsorption tower A. And, at the same time, the oxygen gas that is not adsorbed by the adsorbent in the adsorption tower A is led out of the adsorption tower A from the circulation path 120, and an adsorption process of supplying the oxygen gas again as a raw material gas to the ozone generator 3 via the circulation blower 121 and the buffer tank 122 is carried out (step ST01 in FIG. 2). At this time, the pressure inside the adsorption tower A is in a pressure state greater than the atmospheric pressure. And, when the adsorption process of the adsorption tower A ends, the introduction of ozone from the ozone generator 3 to the adsorption tower A is stopped.

[0015] Next, the first supply unit 4 introduces dry air as the first carrier gas into the adsorption tower A in the desorption process via the first carrier gas introduction path 103. The introduced first carrier gas sweeps away the ozone adsorbed on the adsorbent of the adsorption tower A through the carrier gas outlet path 104, carrying it out of the adsorption tower A, and the first desorption process (step ST02 in Figure 2) is performed. At this time, dry air is introduced into the adsorption tower A, so the pressure inside the adsorption tower A is reduced to approximately atmospheric pressure. Note that in this example, the carrier gas outlet path 104 through which the ozone carried by the first carrier gas passes is led out of the device via the pressure reduction section 5, but this is not the only option, and in the first desorption process, the ozone may be led out directly to the outside of the device without passing through the pressure reduction section 5.

[0016] Next, after stopping the introduction of the first carrier gas, a vacuum desorption process (step ST03 in Figure 2) is performed in which the inside of adsorption tower A is depressurized by the depressurization unit 5 via the carrier gas outlet path 104 until the pressure inside adsorption tower A is lower than atmospheric pressure. At this time, components of the first carrier gas remaining inside adsorption tower A and in the carrier gas outlet path 104 are exhausted. Therefore, the accumulation of nitrogen gas inside adsorption tower A can be reduced, and the amount of NOx gas generated due to the increase in nitrogen gas in the circulation path 120 in the next adsorption process (step ST01) can be reduced. This suppresses the decrease in ozone generation efficiency and reduces nitrogen oxides that cause corrosion of the paths, etc. Then, the depressurization by the depressurization unit 5 is terminated, and the process returns to the adsorption process (step ST01 in Figure 2).

[0017] As shown above, the effects described above can be obtained if the pressure inside adsorption tower A in the vacuum desorption process is lower than atmospheric pressure. However, in order to reliably obtain these effects, the following should be considered.

[0018] For example, if the nitrogen concentration in adsorption tower A during the adsorption process is C1, the pressure value in adsorption tower A is P1, the nitrogen concentration of the first carrier gas in the first desorption process is C2, and the pressure value in adsorption tower A during the vacuum desorption process is P2, C1×P1≧C2×P2 (Formula 1) The pressure in adsorption tower A is reduced until the following relationship is achieved.

[0019] By reducing the pressure in adsorption tower A until the relationship shown in (Equation 1) above is met, and decreasing the partial pressure (concentration × pressure) of nitrogen gas in the vacuum desorption process (step ST03) to less than or equal to the partial pressure of nitrogen gas in the adsorption process (step ST01), the amount of nitrogen gas adsorbed on the adsorbent in adsorption tower A at the end of the desorption process can be reliably reduced to less than that during the adsorption process. Therefore, the accumulation of nitrogen gas in adsorption tower A can be reliably reduced, and the amount of NOx gas generated due to the increase in nitrogen gas in the circulation path 120 in the next adsorption process (step ST01) can be reliably reduced.

[0020] According to the ozone supply system of Embodiment 1 configured as described above, An ozone generator that produces ozone from oxygen supplied from an oxygen source, An adsorption tower houses an adsorbent material for adsorbing ozone generated by the ozone generator, and alternately repeats an adsorption step of adsorbing ozone onto the adsorbent material and a desorption step of desorbing ozone from the adsorbent material. In the adsorption process, a circulation path is provided for circulating oxygen that was not adsorbed by the adsorbent from the adsorption tower to the ozone generator. The first supply unit of the first carrier gas, In the desorption process, a carrier gas introduction path is provided for introducing the first carrier gas from the first supply unit into the adsorption tower, In the desorption process, a carrier gas outlet path is provided for releasing the ozone entrained in the first carrier gas to the outside of the adsorption tower. The desorption process includes a depressurization section that reduces the pressure inside the adsorption tower until it becomes lower than atmospheric pressure. This can suppress the rise in nitrogen concentration inside the adsorption tower.

[0021] Furthermore, according to the ozone supply method of Embodiment 1 as described above, The adsorption process involves adsorbing the generated ozone onto an adsorbent stored in an adsorption tower, simultaneously releasing the oxygen that was not adsorbed by the adsorbent from the adsorption tower, reintroducing it as a raw material gas into an ozone generator to regenerate ozone, and supplying it back to the adsorption tower. After the adsorption process is completed, a first desorption process is performed in which a first carrier gas is introduced into the adsorption tower, the ozone adsorbed on the adsorbent is desorbed along with the first carrier gas, and then discharged outside the adsorption tower. The system includes a vacuum desorption step in which, after stopping the introduction of the first carrier gas, the pressure inside the adsorption tower is reduced until it falls below atmospheric pressure. This can suppress the rise in nitrogen concentration inside the adsorption tower.

[0022] Furthermore, according to the ozone supply method of Embodiment 1 as described above, In the vacuum desorption process, P1 is the pressure value inside the adsorption tower in the adsorption process. P2 is the pressure value inside the adsorption tower in the vacuum desorption process. The nitrogen concentration of the adsorption tower in the adsorption process is C1, If the nitrogen concentration of the first carrier gas in the first desorption step is C2, C1 × P1 ≥ C2 × P2 The depressurization of the adsorption tower is performed until this condition is reached. By reducing the pressure of nitrogen in the vacuum desorption process to a level lower than or equal to that in the adsorption process, the amount of nitrogen adsorbed by the adsorbent becomes equal to or less than that in the adsorption tower, thereby suppressing the retention of large amounts of nitrogen in the adsorption tower.

[0023] Embodiment 2. Figure 3 is a block diagram showing the configuration of the ozone supply system according to Embodiment 2. Figure 4 is a flowchart showing the steps of an ozone supply method using the ozone supply system shown in Figure 3. Figure 5 is a flowchart showing the steps of another ozone supply method using the ozone supply system shown in Figure 3.

[0024] In the figure, parts similar to those in Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted. In Figure 3, the ozone supply system 1 is a second supply unit in which the oxygen source 2 supplies oxygen gas as a second carrier gas having a nitrogen concentration lower than that of the first carrier gas. The oxygen source 2 introduces the second carrier gas to adsorption tower A or adsorption tower B in the desorption process via the second carrier gas introduction path 105. The system is also equipped with a carrier gas switching valve 6 that switches the supply of the first carrier gas and the second carrier gas to adsorption tower A or adsorption tower B in the desorption process.

[0025] Next, the ozone supply method of the ozone supply system of Embodiment 2 configured as described above will be explained. First, the adsorption process of the adsorption tower A is performed, similar to Embodiment 1 (step ST01 in Figure 4). Next, in the desorption process, the first supply unit 4 introduces dry air as the first carrier gas via the first carrier gas introduction path 103 into the adsorption tower A. The introduced first carrier gas sweeps the ozone adsorbed on the adsorbent of the adsorption tower A out of the adsorption tower A together with the first carrier gas via the carrier gas outlet path 104, and the first desorption process (step ST02 in Figure 4) is performed.

[0026] Next, after stopping the introduction of the first carrier gas, oxygen gas is introduced into the adsorption tower A from the oxygen source 2 via the second carrier gas introduction path 105 as the second carrier gas. The introduced second carrier gas then scavenges the ozone adsorbed on the adsorbent material of the adsorption tower A and the first carrier gas remaining in the adsorption tower A out of the adsorption tower A via the carrier gas discharge path 104, together with the second carrier gas, and the second desorption process (step ST04 in Figure 4) is carried out.

[0027] In this way, the first carrier gas remaining in adsorption tower A and carrier gas outlet path 104 is replaced with the second carrier gas and scavenged out of adsorption tower A. Therefore, the accumulation of nitrogen gas in adsorption tower A can be reduced, and the amount of NOx gas generated due to the increase in nitrogen gas in the circulation path 120 in the next adsorption process (step ST01) can be reduced. This reduces nitrogen oxides, which cause a decrease in ozone generation efficiency and corrosion of the path, etc. Then, the introduction of the second carrier gas is stopped and the process returns to the adsorption process (step ST01 in Figure 2).

[0028] Furthermore, another example of the ozone supply method of Embodiment 2 will be described. After the second desorption step described above, and before the adsorption step, after stopping the introduction of the second carrier gas, a vacuum desorption step (step ST05 in Figure 5) is performed in which the inside of the adsorption tower A is depressurized by the depressurization unit 5 via the carrier gas outlet path 104 until the pressure inside the adsorption tower A is lower than atmospheric pressure. At this time, the components of the first carrier gas and the second carrier gas that remain in the adsorption tower A without being replaced by the second carrier gas are exhausted.

[0029] Therefore, the accumulation of nitrogen gas in adsorption tower A can be further reduced, and the amount of NOx gas generated due to the increase in nitrogen gas in the circulation path 120 in the next adsorption process (step ST01) can be further reduced. This further suppresses the decrease in ozone generation efficiency and further reduces nitrogen oxides, which cause corrosion of the path and other components. After stopping the depressurization by the depressurization unit 5, the process returns to the adsorption process (step ST01 in Figure 5).

[0030] As shown above, the effects described above can be obtained if the pressure inside adsorption tower A in the vacuum desorption process is lower than atmospheric pressure. However, in order to reliably obtain these effects, the following should be considered.

[0031] For example, if the nitrogen concentration in adsorption tower A during the adsorption process is C1, the pressure value in adsorption tower A is P1, the nitrogen concentration of the first carrier gas in the first desorption process is C2, and the pressure value in adsorption tower A during the vacuum desorption process is P2, C1×P1≧C2×P2 (Formula 1) The pressure in adsorption tower A is reduced until the following relationship is achieved.

[0032] By reducing the pressure in adsorption tower A until the relationship shown in (Equation 1) above is met, and decreasing the partial pressure (concentration × pressure) of nitrogen gas in the vacuum desorption process (step ST03) to less than or equal to the partial pressure of nitrogen gas in the adsorption process (step ST01), the amount of nitrogen gas adsorbed on the adsorbent in adsorption tower A at the end of the desorption process can be reliably reduced to less than that during the adsorption process. Therefore, the accumulation of nitrogen gas in adsorption tower A can be reliably reduced, and the amount of NOx gas generated due to the increase in nitrogen gas in the circulation path 120 in the next adsorption process (step ST01) can be reliably reduced.

[0033] The ozone supply system of Embodiment 2 configured as described above provides the same effects as Embodiment 1, The system includes a second supply unit for a second carrier gas having a nitrogen concentration lower than that of the first carrier gas, The second supply unit is connected to the carrier gas introduction path via a carrier gas switching valve that switches the supply of the first carrier gas and the second carrier gas to the adsorption tower. The carrier gas discharge path discharges the ozone entrained in the second carrier gas during the desorption process to the outside of the adsorption tower. This further suppresses the rise in nitrogen concentration within the adsorption tower.

[0034] Furthermore, according to the ozone supply method of Embodiment 2 as described above, The adsorption process involves adsorbing the generated ozone onto an adsorbent stored in an adsorption tower, simultaneously releasing the oxygen that was not adsorbed by the adsorbent from the adsorption tower, reintroducing it as a raw material gas into an ozone generator to regenerate ozone, and supplying it back to the adsorption tower. After the adsorption process is completed, a first desorption process is performed in which a first carrier gas is introduced into the adsorption tower, the ozone adsorbed on the adsorbent is desorbed along with the first carrier gas, and then discharged outside the adsorption tower. The system includes a second desorption step in which, after stopping the introduction of the first carrier gas, a second carrier gas with a nitrogen concentration lower than that of the first carrier gas is introduced to desorb the ozone adsorbed on the adsorbent and discharge it outside the adsorption tower, and the first carrier gas remaining in the adsorption tower is replaced with the second carrier gas. This can suppress the rise in nitrogen concentration inside the adsorption tower.

[0035] Furthermore, according to the ozone supply method of Embodiment 2 as described above, The system includes a vacuum desorption step in which, after stopping the introduction of the second carrier gas, the pressure inside the adsorption tower is reduced until it falls below atmospheric pressure. This further suppresses the rise in nitrogen concentration within the adsorption tower.

[0036] Furthermore, according to the ozone supply method of Embodiment 2 as described above, In the vacuum desorption process, P1 is the pressure value inside the adsorption tower in the adsorption process. P2 is the pressure value inside the adsorption tower in the vacuum desorption process. The nitrogen concentration of the adsorption tower in the adsorption process is C1, If the nitrogen concentration of the first carrier gas in the first desorption step is C2, C1 × P1 ≥ C2 × P2 The depressurization of the adsorption tower is performed until this condition is reached. By reducing the pressure of nitrogen in the vacuum desorption process to a level lower than or equal to that in the adsorption process, the amount of nitrogen adsorbed by the adsorbent becomes equal to or less than that in the adsorption tower, thereby suppressing the retention of large amounts of nitrogen in the adsorption tower.

[0037] Although this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed herein. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Explanation of Symbols]

[0038] 1 Ozone supply system, 101 Ozone introduction path, 103 First carrier gas introduction path, 104 Carrier gas outlet path, 105 Second carrier gas introduction path, 11 Switching valve, 12 Switching valve, 120 Circulation path, 121 Circulation blower, 122 Buffer tank, 13 Switching valve, 14 Switching valve, 15 Switching valve, 16 Switching valve, 17 Switching valve, 18 Switching valve, 2 Oxygen source, 3 Ozone generator, 4 First supply unit, 5 Pressure reducing unit, 6 Carrier gas switching valve.

Claims

1. An ozone generator that produces ozone from oxygen supplied from an oxygen source, An adsorption tower houses an adsorbent material for adsorbing ozone generated by the ozone generator, and alternately repeats an adsorption step of adsorbing ozone onto the adsorbent material and a desorption step of desorbing ozone from the adsorbent material. In the adsorption process, a circulation path is provided for circulating oxygen that was not adsorbed by the adsorbent from the adsorption tower to the ozone generator. The first supply unit of the first carrier gas, In the desorption process, a carrier gas introduction path is provided for introducing the first carrier gas from the first supply unit into the adsorption tower, In the desorption process, a carrier gas outlet path is provided for releasing the ozone entrained in the first carrier gas to the outside of the adsorption tower. In the aforementioned desorption process, a depressurization section is provided to reduce the pressure inside the adsorption tower until it becomes lower than atmospheric pressure, The system includes a second supply unit for a second carrier gas having a nitrogen concentration lower than that of the first carrier gas, The second supply unit is connected to the carrier gas introduction path via a carrier gas switching valve that switches the supply of the first carrier gas and the second carrier gas to the adsorption tower. The carrier gas discharge path is an ozone supply system that discharges ozone entrained in the second carrier gas during the desorption process to the outside of the adsorption tower.

2. The adsorption process involves adsorbing the generated ozone onto an adsorbent stored in an adsorption tower, simultaneously releasing the oxygen that was not adsorbed by the adsorbent from the adsorption tower, reintroducing it as a raw material gas into an ozone generator to regenerate ozone, and supplying it back to the adsorption tower. After the adsorption process is completed, a first desorption process is performed in which a first carrier gas is introduced into the adsorption tower, the ozone adsorbed on the adsorbent is desorbed along with the first carrier gas, and then discharged outside the adsorption tower. An ozone supply method comprising: stopping the introduction of the first carrier gas; introducing a second carrier gas having a nitrogen concentration lower than that of the first carrier gas to desorb the ozone adsorbed on the adsorbent and discharge it outside the adsorption tower; and replacing the first carrier gas remaining in the adsorption tower with the second carrier gas.

3. The ozone supply method according to claim 2, further comprising a vacuum desorption step of reducing the pressure inside the adsorption tower until the pressure inside the adsorption tower becomes lower than atmospheric pressure after stopping the introduction of the second carrier gas.

4. In the vacuum desorption process, P1 is the pressure value inside the adsorption tower in the adsorption process. P2 is the pressure value inside the adsorption tower in the vacuum desorption process. The nitrogen concentration of the adsorption tower in the adsorption process is C1, If the nitrogen concentration of the first carrier gas in the first desorption step is C2, C1 × P1 ≥ C2 × P2 The ozone supply method according to claim 3, wherein the pressure of the adsorption tower is reduced until the following condition is met.

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