Gas homogenization device, gas homogenization method, hydrogen gas production facility and operation method of the same, and gasification-melting furnace facility and operation method of the same

Abstract

To provide a gas homogenization device capable of sufficiently reducing the influence of temporal composition fluctuations of a gas while suppressing an increase in power.SOLUTION: A gas homogenization device comprises a pressure swing adsorption device for purifying a gas and a plurality of tanks into which a first gas whose composition fluctuates over time is sequentially introduced, wherein the first gas comprises at least a part of off-gas discharged from the pressure swing adsorption device, the off-gas is separated into a first off-gas and a second off-gas having a lower average concentration of hydrogen than the first off-gas, and the separated first off-gas is sequentially introduced as the first gas into the plurality of tanks.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas homogenization device, a gas homogenization method, a hydrogen gas production method, a hydrogen gas production facility and an operation method thereof, a gasification melting furnace facility and an operation method thereof, a steelmaking method, a heat treatment method, and a method for producing iron ore. [Background technology]

[0002] Various plants generate various off-gases. For example, off-gases containing hydrogen gas are generated in the depressurization and regeneration processes of PSA units. Patent Document 1 proposes a technology for suppressing fluctuations in the hydrogen gas concentration in the off-gases discharged from the PSA unit by circulating and mixing the off-gases between a first tank and a second tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-177615 Summary of the Invention [Problem to be solved by the invention]

[0004] To homogenize off-gas using the method of Patent Document 1, a large amount of off-gas needs to be circulated between tanks. Increasing the amount of circulated off-gas increases the power required to circulate the off-gas. The present disclosure provides a gas homogenization device and a gas homogenization method that can sufficiently reduce the effects of fluctuations in gas composition over time while suppressing an increase in power. The present disclosure provides a hydrogen gas production facility that can efficiently produce hydrogen gas by effectively utilizing off-gas, and an operating method thereof. The present disclosure provides a gasification melting furnace facility that can efficiently operate by effectively utilizing off-gas, and an operating method thereof. The present disclosure provides a hydrogen gas production method that can effectively utilize off-gas. The present disclosure provides an ironmaking method, a heat treatment method, and an iron ore production method that can effectively utilize refined gas or off-gas obtained in a hydrogen gas production facility. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a gas homogenization device including: a plurality of tanks into which a first gas whose composition varies over time is sequentially introduced; a flow path through which a second gas, which is drawn from at least one of the plurality of tanks and has a reduced range of variation in composition over time compared to the first gas, flows; and a mixer that mixes the second gas with a third gas having a composition different from the first gas and the second gas, and draws out a fourth gas.

[0006] The gas homogenization device includes multiple tanks into which a first gas, whose composition varies over time, is sequentially introduced. These multiple tanks buffer the variation in the composition of the first gas over time and can output a second gas whose composition varies less over time than the first gas. The device also includes a flow path through which the second gas flows and a mixer that mixes the second gas with a third gas and outputs a fourth gas. This gas homogenization device sufficiently reduces the influence of the variation in the composition of the first gas over time, allowing a sufficiently homogenized fourth gas to be obtained. Furthermore, since there is no need to circulate the gas between multiple tanks, an increase in power consumption can be suppressed.

[0007] One aspect of the present disclosure provides a hydrogen gas production facility including the gas homogenization device and a pressure swing adsorption device that purifies hydrogen gas, wherein at least a portion of off-gas containing hydrogen gas that is derived from the pressure swing adsorption device is introduced into the gas homogenization device as the first gas, the third gas containing hydrogen gas and nitrogen gas is introduced into the mixer, and a gas containing the fourth gas is introduced into the pressure swing adsorption device.

[0008] In the hydrogen gas production facility, at least a portion of the off-gas containing hydrogen gas discharged from the pressure swing adsorption unit can be introduced into the pressure swing adsorption unit using the gas homogenizer, thereby making it possible to effectively utilize the hydrogen gas contained in the off-gas and efficiently produce hydrogen gas.

[0009] One aspect of the present disclosure provides a gasification and melting furnace facility including the gas homogenization device, a melting furnace, a charging device provided above the melting furnace, and a first pressure swing adsorption device that purifies nitrogen gas used in the charging device, wherein at least a portion of the off-gas containing oxygen gas derived from the first pressure swing adsorption device is introduced into the gas homogenization device as the first gas, a first oxygen-containing gas containing oxygen is introduced into the mixer as the third gas, and a second oxygen-containing gas containing the fourth gas is introduced into the gasification and melting furnace.

[0010] In the gasification and melting furnace facility, at least a portion of the oxygen-containing off-gas discharged from the first pressure swing adsorption unit can be introduced into the gasification and melting furnace facility using the gas homogenizer, thereby making it possible to effectively utilize the oxygen contained in the off-gas and operate the gasification and melting furnace facility efficiently.

[0011] One aspect of the present disclosure provides a gas homogenization method, including: an introduction step of sequentially introducing a first gas whose composition varies over time into a plurality of tanks; an extraction step of extracting a second gas from at least one of the plurality of tanks, the second gas having a reduced range of variation in composition over time compared to the first gas; and a mixing step of mixing the second gas with a third gas having a composition different from the first gas and the second gas in a mixer to obtain a fourth gas.

[0012] The gas homogenization method includes an introduction step of sequentially introducing a first gas, whose composition varies over time, into multiple tanks. In this introduction step, the variation in the composition of the first gas over time is buffered in the multiple tanks. The method also includes a mixing step of obtaining a fourth gas by mixing a second gas and a third gas, which are discharged in the discharge step and have a reduced range of variation in composition over time compared to the first gas. According to this gas homogenization method, the influence of the variation in the composition of the first gas over time is sufficiently reduced, and a sufficiently homogenized fourth gas can be obtained. Furthermore, since there is no need to circulate the gas between multiple tanks, an increase in power consumption can be suppressed.

[0013] One aspect of the present disclosure provides a method for operating a hydrogen gas production facility including the gas homogenization device and a pressure swing adsorption device that purifies hydrogen gas, the method comprising: a first introduction step of introducing at least a portion of an off-gas containing hydrogen gas derived from the pressure swing adsorption device into the gas homogenization device as the first gas; a second introduction step of introducing the third gas containing hydrogen gas and nitrogen gas into the mixer; a third introduction step of introducing the fourth gas into the pressure swing adsorption device; and a purification step of obtaining hydrogen gas from the fourth gas in the pressure swing adsorption device.

[0014] In the above-described method for operating a hydrogen gas production facility, at least a portion of the off-gas containing hydrogen gas discharged from the pressure swing adsorption unit can be introduced into the pressure swing adsorption unit using the gas homogenizer, thereby making it possible to effectively utilize the hydrogen gas contained in the off-gas and efficiently produce hydrogen gas.

[0015] One aspect of the present disclosure provides a method for operating a gasification and melting furnace facility including the gas homogenization device, a gasification and melting furnace, and a first pressure swing adsorption device that purifies nitrogen gas used in a charging device of the gasification and melting furnace, the method including a first introduction step of introducing at least a portion of the off-gas containing oxygen gas derived from the first pressure swing adsorption device into the gas homogenization device as the first gas, a second introduction step of introducing a first oxygen-containing gas containing oxygen as the third gas into the mixer, and a third introduction step of introducing a second oxygen-containing gas containing the fourth gas into the gasification and melting furnace.

[0016] In the method for operating the gasification and melting furnace facility, at least a portion of the oxygen-containing off-gas discharged from the first pressure swing adsorption unit can be introduced into the gasification and melting furnace facility using the gas homogenizer, thereby making it possible to effectively utilize the oxygen contained in the off-gas and operate the gasification and melting furnace facility efficiently.

[0017] One aspect of the present disclosure provides a method for producing hydrogen gas using a hydrogen gas production facility including: a plurality of tanks into which a first gas containing hydrogen gas and having a composition that varies over time is sequentially introduced; a flow path through which a second gas that is extracted from at least one of the plurality of tanks and has a reduced range of variation in composition over time compared to the first gas flows; a mixer that mixes the second gas with a third gas that has a composition different from the first gas and the second gas to extract a fourth gas; and a pressure swing adsorption apparatus having an adsorption tower, the method including: an adsorption step of introducing the fourth gas containing hydrogen gas and a different component different from the hydrogen gas into the adsorption tower, and adsorbing the different component onto an adsorbent in the adsorption tower to obtain hydrogen gas; the depressurization step of stopping the introduction of the fourth gas, lowering the pressure in the adsorption tower to a level lower than that in the adsorption step, and discharging the gas remaining in the adsorption tower; the exhaust step of further lowering the pressure in the adsorption tower to a level lower than that in the depressurization step, and discharging the gas remaining in the adsorption tower; the regeneration step of discharging the different components adsorbed by the adsorbent together with the gas remaining in the adsorption tower; and the pressurization step of introducing the fourth gas into the adsorption tower after the regeneration step, thereby pressurizing the inside of the adsorption tower; and the fractionation step of fractionating the off-gas discharged in the depressurization step, the exhaust step, and the regeneration step to obtain a plurality of off-gases having different average concentrations of hydrogen gas.

[0018] In the hydrogen gas production method, the off-gas generated from the adsorption tower of the pressure swing adsorption device is fractionated to obtain multiple off-gases with different average hydrogen gas concentrations. Therefore, each of the multiple off-gases can be used for a different purpose. This allows the off-gas to be effectively utilized according to its average hydrogen gas concentration while obtaining a purified gas with a high hydrogen gas concentration.

[0019] One aspect of the present disclosure provides a method for producing iron and steel, in which the hydrogen gas and / or the off-gases obtained by the hydrogen gas production method are used in an iron and steel production process. This method for producing iron and steel can effectively utilize the purified gas or off-gases obtained in the hydrogen gas production facility, thereby reducing carbon dioxide emissions.

[0020] One aspect of the present disclosure provides a method for making iron, which includes introducing the hydrogen gas and / or the plurality of off-gases obtained by the above-described method for producing hydrogen gas into a blast furnace. This method for making iron can effectively utilize the refined gas or the off-gas obtained in the hydrogen gas production facility, thereby reducing carbon dioxide emissions.

[0021] One aspect of the present disclosure provides a heat treatment method in which the hydrogen gas and / or the plurality of off-gases obtained by the above-described hydrogen gas production method are introduced into a heating furnace. This heat treatment method makes it possible to effectively utilize the purified gas or off-gases obtained in the hydrogen gas production facility, thereby reducing carbon dioxide emissions.

[0022] One aspect of the present disclosure provides a method for producing iron ore, in which the hydrogen gas and / or the plurality of off-gases obtained by the above-described hydrogen gas production method are introduced into a direct reduction furnace. In this production method, the refined gas or off-gas obtained in the hydrogen gas production facility can be effectively utilized. This makes it possible to reduce carbon dioxide emissions. The direct reduction furnace may be a shaft furnace or a fluidized bed furnace. [Effects of the Invention]

[0023] The present disclosure can provide a gas homogenization device and a gas homogenization method that can sufficiently reduce the effects of fluctuations in gas composition over time while suppressing an increase in power.The present disclosure can provide hydrogen gas production equipment and an operating method thereof that can efficiently produce hydrogen gas by effectively utilizing off-gas.The present disclosure can provide a gasification melting furnace equipment and an operating method thereof that can efficiently operate by effectively utilizing off-gas.The present disclosure can provide a hydrogen gas production method that can effectively utilize off-gas.The present disclosure can provide an ironmaking method, a heat treatment method, and an iron ore production method that can effectively utilize refined gas or off-gas obtained in a hydrogen gas production equipment. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 illustrates an embodiment of a gas homogenizer and hydrogen gas production facility. [Figure 2] 1 is a graph showing an example of fluctuation over time in the composition of off-gas generated in a pressure swing adsorption unit that purifies hydrogen gas. [Figure 3] FIG. 1 illustrates an example of a pressure swing adsorption device. [Figure 4] FIG. 1 illustrates another example of a pressure swing adsorption device. [Figure 5] FIG. 1 illustrates another embodiment of a gas homogenization apparatus and hydrogen gas production facility. [Figure 6] 1 is a graph showing an example of fluctuation over time in the composition of off-gas generated in a pressure swing adsorption unit that purifies hydrogen gas. [Figure 7] FIG. 1 is a diagram showing an embodiment of a gasification and melting furnace facility. [Figure 8] FIG. 2 is a graph showing fluctuations in the composition (volume ratio of oxygen gas and nitrogen gas) of the off-gas discharged from a pressure swing adsorption unit that produces nitrogen. [Figure 9] 1 shows the simulation results of Example 1. (A) shows the simulation results for oxygen gas concentration, and (B) shows the simulation results for nitrogen gas concentration. [Figure 10] 1 shows the simulation results of Comparative Example 1. (A) shows the simulation results for oxygen gas concentration, and (B) shows the simulation results for nitrogen gas concentration. [Figure 11] 10 shows the simulation results of Example 2. [Figure 12] 10 shows the simulation results of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings where necessary. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same reference numerals will be used for the same elements or elements having the same functions, and redundant explanations will be omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships based on the orientation of the reference numerals shown in the drawings. Furthermore, the dimensional ratios of each element are not limited to those shown in the drawings.

[0026] A gas homogenization device according to one embodiment includes a plurality of tanks into which a first gas whose composition varies over time is sequentially introduced, a flow path through which a second gas, which is drawn from at least one of the plurality of tanks and has a reduced range of variation in composition over time compared to the first gas, flows, and a mixer that mixes the second gas with a third gas having a composition different from the first and second gases, to draw out a fourth gas.

[0027] The first gas is not particularly limited as long as its composition fluctuates over time. For example, it may be off-gas discharged from a pressure swing adsorption apparatus. The number of tanks may be two or more, three or more, or five or more. "The first gas is introduced sequentially" means that the timing at which the first gas is introduced varies. For example, if the multiple tanks include a first tank, a second tank, and a third tank, the first gas is introduced into the first tank during a first predetermined period (first period), the first gas is introduced into the second tank during a next predetermined period (second period), and the first gas is introduced into the third tank during a next predetermined period (third period). In this way, the tank to which the first gas is introduced changes every time a predetermined period elapses. The order in which the first gas is introduced is not limited, and may be, for example, the first tank, the third tank, and the second tank. The fluctuation range of the gas composition is the difference between the minimum and maximum concentrations of a predetermined component. When a gas contains three or more components, the fluctuation range is determined based on the component with the largest difference between the minimum and maximum values. The period during which the first gas is introduced into each tank and the timing for switching the tank into which the first gas is introduced are not particularly limited as long as the fluctuation range of the composition of the second gas drawn out from each tank is reduced to be smaller than the fluctuation range of the composition of the first gas.

[0028] The composition of the first gas may vary periodically. The pressure swing adsorption apparatus discharges off-gas during depressurization and regeneration of the adsorption tower, along with a predetermined high-purity gas. This off-gas is an example of a first gas whose composition varies periodically. The period t during which the first gas is continuously introduced into each tank may be shorter or longer than the period p of the composition fluctuation of the first gas. Alternatively, the period t may be equal to the period p. For example, the ratio of the period t to the period p may be 0.1 to 1, from the viewpoint of obtaining a second gas whose composition fluctuation range is sufficiently reduced while preventing an excessive number of tanks. When the ratio is 1, the tank into which the first gas is introduced is switched for each period of the composition fluctuation of the first gas.

[0029] 1 includes a pressure swing adsorption apparatus 10 that produces high-purity hydrogen gas (H gas), and a gas homogenization apparatus 100 that homogenizes an off-gas (first gas) whose composition varies over time and is generated in the pressure swing adsorption apparatus 10. The gas homogenization apparatus 100 includes multiple tanks 20, a flow path 12 that sequentially introduces the off-gas (first gas) derived from the pressure swing adsorption apparatus 10 into a first tank 21 and a second tank 22 of the multiple tanks 20, a flow path 52 through which a second gas derived from the multiple tanks 20 flows, and a mixer 30 that is connected to flow path 52 and mixes the second gas with a third gas.

[0030] Flow path 12 is connected to flow path 13, which discharges the off-gas outside the system. For example, a portion of the off-gas having a low hydrogen gas concentration may or may not be discharged outside the system using flow path 13. At least a portion of the off-gas containing hydrogen gas generated in pressure swing adsorption apparatus 10 flows through flow path 12 and is introduced into first tank 21 or second tank 22.

[0031] The flow path 12 branches into two paths to introduce the off-gas into the first tank 21 and the second tank 22. Valves SV1 and SV2 are provided in the branched flow paths, respectively. By opening and closing SV1 and SV2, the introduction destination of the off-gas flowing through the flow path 12 can be switched. In other words, SV1 and SV2 constitute a switching unit that switches the tank into which the off-gas is introduced. By operating SV1 and SV2, the off-gas flowing through the flow path 12 can be introduced alternately into the first tank 21 and the second tank 22.

[0032] When the pressure swing adsorption apparatus 10 is a PSA hydrogen gas purification apparatus (H-PSA) that purifies hydrogen gas, an off-gas containing hydrogen gas and gases other than hydrogen gas is generated in addition to high-purity (99.9% by volume or higher) hydrogen gas. The composition of such off-gas varies over time as the depressurization step, exhaust step, regeneration step, and pressurization step are repeated in the pressure swing adsorption apparatus 10. In this case, the composition of the off-gas varies periodically, with time T shown in FIG. 2 being one period (period p). Hereinafter, this off-gas in this example will be referred to as the "first gas." The hydrogen gas concentration in the first gas (off-gas) varies periodically between 35 and 45% by volume. The nitrogen gas concentration in the first gas varies periodically between 55 and 65% by volume. The fluctuation range of the composition of the first gas is 10% by volume.

[0033] In FIG. 1, SV1 is opened (SV2 is closed) to introduce the first gas into the first tank 21 during the first cycle. Thereafter, SV1 is closed and SV2 is opened, and the first gas is introduced into the second tank 22 during the next cycle. As a result, the first gas for one cycle is introduced into each of the first tank 21 and the second tank 22. Therefore, the compositions of the first gas stored in the first tank 21 and the second tank 22 are homogenized. In this way, a second gas having less fluctuation over time than the first gas is obtained in the first tank 21 and the second tank 22. Furthermore, the compositions of the first gas stored in the first tank 21 and the second tank 22 become equivalent. In this way, a second gas having less fluctuation over time in composition than the first gas is obtained.

[0034] The first tank 21 and the second tank 22 each repeatedly introduce the first gas, homogenize the first gas (generate the second gas), and discharge the second gas. As described above, SV1 is closed and SV2 is opened, and once the introduction of off-gas into the second tank 22 begins, the valve OV1 in the flow path 52 connected to the first tank 21 is opened. This causes the second gas generated in the first tank 21 to flow through the flow path 52. The homogenized off-gas (second gas) flows through the flow path 52 and is introduced into the mixer 30.

[0035] When the inventory of the second gas in first tank 21 becomes low, OV1 in flow path 52 is closed and SV1 in flow path 12 is opened. At the same time, SV2 in flow path 12 is closed and valve OV2 in flow path 52 is opened. As a result, the destination of the first gas discharged from pressure swing adsorption device 10 is switched from second tank 22 to first tank 21, and the source of the second gas discharged to mixer 30 is switched from first tank 21 to second tank 22. In this way, gas homogenization device 100 and hydrogen gas production facility 200 can be operated continuously.

[0036] The mixer 30 is connected to a flow path 52 for supplying a second gas and a flow path 53 for supplying a third gas. The third gas may contain hydrogen gas and nitrogen gas obtained by decomposing ammonia, for example, as shown in the following formula (1). The content of hydrogen gas in the third gas may be 65 to 85 volume %, or 70 to 80 volume %. The content of nitrogen gas in the third gas may be 15 to 35 volume %, or 20 to 30 volume %. The flow paths 52 and 53 are provided with flow control valves FV1 and FV2 for adjusting the flow rates of the second gas and the third gas. When the composition of the second gas fluctuates, the flow rates of the second gas and the third gas may be adjusted using FV1 and FV2 to suppress fluctuations in the composition of the fourth gas, which will be described later. 2NH3 → N2 + 3H2 (1)

[0037] The mixer 30 has a vessel body 38 composed of a cylindrical side wall, an upper plate connected to the upper end of the side wall, and a bottom plate connected to the lower end of the side wall, and baffles 31, 32, and 33 provided inside the vessel body 38. The baffles 31 and 33 are disk-shaped, and ring-shaped gaps are provided between the baffles 31 and 33 and the inner surface of the side wall. The baffle 32 is ring-shaped and has a circular through-hole in its center. The flow paths 52 and 53 are connected to the upper plate of the vessel body 38, and the second gas and the third gas are introduced from the top of the vessel body 38.

[0038] A zigzag flow path is formed within the vessel body 38 by baffles 31, 32, and 33. The second gas and the third gas are mixed while flowing through such a flow path. In FIG. 1, the mixer 30 is provided with three baffles, but this is not limited to this. From the viewpoint of sufficiently mixing and homogenizing the second gas and the third gas in the mixer 30, the number of baffles may be five or more, seven or more, or ten or more. The mixer 30 is not limited to a shape constituted by a vessel body and baffles, and may be constituted by, for example, a tubular body that forms a zigzag flow path. Various mixers such as a mixer, a blender, an injector, etc. may be used as the mixer 30.

[0039] The gas obtained by sufficiently mixing the second gas and the third gas in the mixer 30 is referred to as the "fourth gas." A flow path 44 is connected to the bottom plate of the container body 38 of the mixer 30. A compressor 40 is provided to the flow path 44. This compressor 40 allows the first gas, second gas, third gas, and fourth gas to circulate in the gas homogenization device 100. The gas homogenization device 100 is provided with a power source for circulating the gases in this manner, but since there is no need to circulate the first gas through multiple tanks 20, an increase in power required for homogenization can be suppressed. The fourth gas generated in the mixer 30 is discharged from the mixer 30 to the flow path 44.

[0040] The fourth gas includes a third gas containing hydrogen gas and nitrogen gas obtained by decomposing ammonia, and a second gas obtained by homogenizing the gas composition of the first gas (off-gas) output from the pressure swing adsorption device 10. As shown in FIG. 2, this first gas contains hydrogen gas, and its concentration fluctuates periodically. However, in the gas homogenization device 100, a second gas with reduced periodic fluctuations is produced in multiple tanks 20, and the third gas and the second gas with reduced periodic fluctuations are mixed in the mixer 30. This sufficiently suppresses fluctuations in composition over time, allowing a sufficiently homogenized fourth gas to be obtained.

[0041] The fourth gas flows through flow path 44 and is introduced into pressure swing adsorption apparatus 10. The fourth gas contains the hydrogen gas that was originally contained in the first gas. Therefore, hydrogen gas production facility 200 can efficiently produce hydrogen gas by effectively utilizing the off-gas. The fourth gas introduced into hydrogen gas production facility 200 has sufficiently suppressed fluctuations in its composition over time. Therefore, pressure swing adsorption apparatus 10 can be operated sufficiently stably.

[0042] As shown in Figure 3, the pressure swing adsorption system 10 has four adsorption towers (first adsorption tower 10A, second adsorption tower 10B, third adsorption tower 10C, and fourth adsorption tower 10D). The first adsorption tower 10A, second adsorption tower 10B, third adsorption tower 10C, and fourth adsorption tower 10D contain adsorbents that adsorb gases other than hydrogen gas (such as nitrogen gas). Each adsorption tower may purify hydrogen gas by repeatedly performing an adsorption step, a depressurization step, an evacuation step, a regeneration step, and a pressurization step.

[0043] The adsorption process is a process of recovering hydrogen gas by adsorbing gases other than hydrogen gas contained in the fourth gas (raw material gas) onto the adsorbent in the adsorption tower under high pressure. The depressurization process is a process of depressurizing the adsorption tower after the adsorption process to lower the pressure in the adsorption tower compared to the adsorption process and discharging the hydrogen gas and fourth gas remaining in the adsorption tower. The off-gas generated at this time contains the hydrogen gas and fourth gas remaining in the adsorption tower. The exhaust process is a process of discharging the fourth gas and hydrogen gas remaining in the adsorption tower by opening to atmospheric pressure or using a vacuum pump. The exhaust process is a process of further reducing the pressure in the adsorption tower compared to the depressurization process and discharging the gas remaining in the adsorption tower. The regeneration process is a process of further reducing the pressure in the adsorption tower by opening to atmospheric pressure or using a vacuum pump and discharging the fourth gas and hydrogen gas remaining in the adsorption tower as well as impurities adsorbed to the adsorbent. The pressurization process is a process of introducing hydrogen gas into the adsorption tower after the regeneration process has been completed to pressurize the adsorption tower.

[0044] 3 shows a state in which the first adsorption tower 10A is performing an adsorption process, the second adsorption tower 10B is performing a depressurization process and an evacuation process, the third adsorption tower 10C is performing a regeneration process, and the fourth adsorption tower 10D is performing a pressurization process. High-purity hydrogen gas is obtained from the first adsorption tower 10A. Meanwhile, off-gases containing hydrogen gas and other gases are generated from the second adsorption tower 10B and the third adsorption tower 10C. All of the off-gases generated in this manner may be introduced into multiple tanks 20 via flow path 12.

[0045] In the pressure swing adsorption system 10 shown in Figure 4, the flow path connected to the lower part of the second adsorption tower 10B performing the depressurization step and the evacuation step and the third adsorption tower 10C performing the regeneration step branches into multiple paths. That is, the flow path branches into a flow path 12 connected to the multiple tanks 20 shown in Figure 1 and a flow path 14 that is not connected to the multiple tanks 20 shown in Figure 1 but is connected to equipment outside the system. The hydrogen gas concentration of the off-gas obtained in the depressurization step and the regeneration step (first off-gas) is, for example, 40% by volume or more on average during the depressurization step and the regeneration step, which is higher than the average hydrogen gas concentration of the off-gas obtained in the evacuation step (second off-gas).

[0046] Of the off-gases discharged from the pressure swing adsorption device 10, only the high-quality off-gas (first off-gas) having a high concentration of hydrogen gas may be introduced as the first gas into the plurality of tanks 20 via the flow path 12. This reduces the concentrations of gas components other than hydrogen gas contained in the fourth gas, thereby reducing the load on the pressure swing adsorption device 10. The low-quality off-gas (second off-gas) having a lower concentration of hydrogen gas than the high-quality off-gas may be circulated through the flow path 14 and used as fuel in a combustion facility, for example. Note that it is not necessary to introduce the entire amount of the high-quality off-gas into the plurality of tanks 20; a portion of the high-quality off-gas may be used for other purposes. Because this high-quality off-gas has a higher calorie content and less fluctuation in composition than the low-quality off-gas, it may also be used as fuel for a generator. By separating the off-gas into multiple gases in this manner, efficient energy utilization can be achieved.

[0047] A hydrogen gas production method may be performed using a pressure swing adsorption apparatus 10 equipped with multiple adsorption towers as shown in FIG. 4. In this hydrogen gas production method, high-purity hydrogen gas is obtained as a purified gas, and a high-quality off-gas (first off-gas) and a low-quality off-gas (second off-gas) can also be obtained. Therefore, this method can also be called a hydrogen gas production method. At least one selected from the group consisting of the purified gas (hydrogen gas), high-quality off-gas, and low-quality off-gas obtained in this manner may be introduced into a blast furnace or used in a steelmaking process. This reduces carbon dioxide emissions associated with steel production. At least one selected from the group consisting of the purified gas (hydrogen gas), high-quality off-gas, and low-quality off-gas may be introduced into a heating furnace and used for heat treatment, or may be introduced into a direct reduction furnace and used for producing iron ore. This reduces carbon dioxide emissions.

[0048] The high-quality off-gas and the low-quality off-gas may have varying hydrogen gas concentrations over time. The average hydrogen gas concentration of the high-quality off-gas is higher than the average hydrogen gas concentration of the low-quality off-gas. The average hydrogen gas concentration of the high-quality off-gas may be 40% by volume or more, or 45% by volume or more.

[0049] 5 includes a pressure swing adsorption apparatus 10 that purifies hydrogen gas, and a gas homogenization apparatus 110 that homogenizes off-gas (first gas) whose composition varies over time and is generated in the pressure swing adsorption apparatus 10. The gas homogenization apparatus 110 includes multiple tanks 20A, a flow path 12 that sequentially introduces the off-gas (first gas) derived from the pressure swing adsorption apparatus 10 into the multiple tanks 20A, flow paths 51, 52, and 54 through which a second gas derived from the multiple tanks 20A flows, a flow path 53 through which a third gas flows, and a mixer 30 that mixes the second gas and the third gas.

[0050] The hydrogen gas production facility 210 in Figure 5 differs from the hydrogen gas production facility 200 in Figure 1 in the number of tanks 20A into which the first gas is introduced and the associated ancillary equipment. The rest of the configuration may be the same as that of the hydrogen gas production facility 200 in Figure 1. Here, the following explanation will focus on the differences from the hydrogen gas production facility 200 in Figure 1.

[0051] The flow path 12 branches into seven paths for introducing the off-gas into a first tank 21, a second tank 22, a third tank 23, a fourth tank 24, a fifth tank 25, a sixth tank 26, and a seventh tank 27 (hereinafter collectively referred to as the "tank groups 21-27"). Valves SV1, SV2, SV3, SV4, SV5, SV6, and SV7 (hereinafter collectively referred to as the "SV1-SV7") are provided on the branched paths, respectively. Opening and closing SV1-SV7 allows the destination of the first gas flowing through the flow path 12 to be switched. That is, SV1-SV7 constitute a switching unit for switching the tank into which the first gas is introduced. Operating SV1-SV7 allows the first gas to be introduced into each tank of the tank groups 21-27 at different times. The first gas may be introduced into each tank of the tank groups 21-27 one by one, or into a group of two or three tanks of the tank groups 21-27.

[0052] At least one flow path selected from the group consisting of flow paths 51 and 52 is connected to tank groups 21 to 27. Valves OV1A, OV2A, OV3A, OV4A, and OV5A are provided on each branch pipe connecting flow path 51 to first tank 21, second tank 22, third tank 23, fourth tank 24, and fifth tank 25. By operating these valves, it is possible to start or stop the delivery of the second gas from first tank 21, second tank 22, third tank 23, fourth tank 24, and fifth tank 25 to flow path 51.

[0053] Valves OV2B, OV3B, OV4B, OV5B, OV6B, and OV7B are provided on the branch pipes connecting the flow path 52 to the second tank 22, the third tank 23, the fourth tank 24, the fifth tank 25, the sixth tank 26, and the seventh tank 27. By operating these valves, it is possible to start or stop the delivery of the second gas from the second tank 22, the third tank 23, the fourth tank 24, the fifth tank 25, the sixth tank 26, and the seventh tank 27 to the flow path 52. In other words, it is possible to switch the tank from which the second gas is delivered.

[0054] The flow paths 51 and 52 are connected to the premixer 30A (second mixer). The premixer 30A has a vessel body 39 composed of a cylindrical side wall, an upper plate connected to the upper end of the side wall, and a bottom plate connected to the lower end of the side wall, and baffles 35, 36, and 37 provided inside the vessel body 39. The baffles 35 and 37 are disk-shaped, and a ring-shaped gap is provided between the baffles 35 and 37 and the inner surface of the side wall. The baffle 36 is ring-shaped, and has a circular through-hole in its center. The flow paths 51 and 52 are connected to the upper plate of the vessel body 39, and the second gas that has flowed through the flow paths 51 and 52 is introduced from the top of the vessel body 39.

[0055] A zigzag flow path is formed within the vessel body 39 by the baffles 35, 36, and 37. The second gases delivered from different tanks are mixed while flowing through these flow paths. This allows the second gas to be sufficiently homogenized. In FIG. 5, the premixer 30A is provided with three baffles, but this is not limited to this. From the viewpoint of sufficiently mixing and homogenizing the second gases in the premixer 30A, the number of baffles may be five or more, seven or more, or ten or more. The premixer 30A is not limited to a shape composed of a vessel body and baffles, as with the mixer 30, and may be composed of, for example, a tubular body forming a zigzag flow path. Various mixers, such as a mixer, a blender, or an injector, may be used as the premixer 30A.

[0056] When the composition of the first gas fluctuates as shown in FIG. 2, the first gas may be introduced into multiple tanks sequentially within one cycle (cycle p) of the composition fluctuation of the first gas. FIG. 6 shows the composition fluctuation of the first gas over one cycle. The horizontal axis of FIG. 6 represents time, and the vertical axis represents the volume ratio of nitrogen gas. In FIG. 6, one cycle is equally divided into six time periods: I, II, III, IV, V, and VI. The tank into which the first gas is introduced may be switched for each of these time periods. Tables 1 and 2 show examples of tank switching.

[0057] [Table 1]

[0058] [Table 2]

[0059] Tables 1 and 2 show the states of the tank groups 21 to 27 in time periods I to VI of cycles 1 to 9. One cycle corresponds to one period. In each cycle, the composition of the first gas (off-gas) varies as shown in FIG. 6. Tables 1 and 2 show cycles 1 to 9, but the number of cycles is not limited, and the same operations as those up to cycle 9 may be repeated from cycle 10 onwards.

[0060] In Tables 1 and 2, "Introduction" indicates that the first gas is being introduced into each tank, "Standby" indicates that the tank is filled with the second gas, and "Discharge" indicates that the second gas is being discharged from each tank to flow path 51 or flow path 52. This "Discharge" discharges all of the second gas from one tank in one time period, whereas "1 / 2 Discharge" discharges all of the second gas from two tanks over two time periods. Therefore, the amount of second gas discharged from each tank per unit time in "1 / 2 Discharge" is half that of "Discharge." "↓" indicates that the same state as in the previous time period continues, and "-" indicates that the tank is essentially empty after the second gas is discharged.

[0061] As shown in Tables 1 and 2, the first gas discharged from pressure swing adsorption unit 10 during time period I in each cycle is introduced into first tank 21. The gas remains in first tank 21 during time periods II to V, where it is homogenized to become the second gas, which is then discharged from first tank 21 during time period VI. The first gas generated during time period IV in each cycle is introduced into fourth tank 24, fifth tank 25, sixth tank 26, or seventh tank 27. The first gas remains in these tanks for a while, where it is homogenized to become the second gas, and is then discharged from each tank during one of these time periods. Because the first gas generated during time periods I and IV has a composition that is generally close to the average composition of the first gas generated in one cycle, fluctuations in the composition of the second gas over time can be sufficiently suppressed even when the second gas is discharged alone.

[0062] In each cycle, the first gas generated during time period III is introduced into the second tank 22, the third tank 23, the fourth tank 24, or the fifth tank 25. In each cycle, the first gas generated during time period V is introduced into the second tank 22, the third tank 23, or the fifth tank 25. The first gas introduced into each tank resides there for a while, where it is homogenized and becomes the second gas. The second gas introduced into each tank and retained there during time period III and the second gas introduced into each tank and retained there during time period V are respectively discharged to flow path 51 or flow path 52 at the same time. These gases are joined and mixed in premixer 30A. This allows for the production of a second gas having a composition roughly similar to the average composition of the first gas generated in one cycle.

[0063] In each cycle, the first gas generated in time period II is introduced into the second tank 22, the fourth tank 24, the sixth tank 26, or the seventh tank 27. In each cycle, the first gas generated in time period VI is introduced into the third tank 23, the fourth tank 24, the fifth tank 25, or the sixth tank 26. The first gas introduced into each tank remains there for a while and is homogenized to become the second gas. The second gas generated and homogenized in time period II and the second gas generated and homogenized in time period VI are respectively introduced into flow path 51 or flow path 52 at the same time. These gases are joined and mixed in premixer 30A. This results in a second gas having a composition roughly similar to the average composition of the first gas generated in one cycle.

[0064] In this way, a second gas with reduced fluctuations in composition over time is obtained. This second gas flows through flow path 54 and is introduced into mixer 30. The components after mixer 30 may be the same as those in the embodiment shown in FIG. 1. In this embodiment, the number of tanks to which the first gas is introduced per one cycle of composition fluctuation of the first gas is six, while the total number of tanks 20A is seven. By making the total number of tanks greater than the number of tanks to which the first gas is introduced per one cycle, the second gas and fourth gas with sufficiently suppressed composition fluctuations can be stably obtained.

[0065] The gas homogenization device of the present disclosure may be included in facilities other than hydrogen gas production facilities, for example, in gasification and melting furnace facilities that treat waste.

[0066] The gasification and melting furnace facility 300 of FIG. 7 includes a carbonaceous bed-type melting furnace 70, a charging device 60 with a double seal mechanism installed at the top of the melting furnace 70, a gas homogenizer 120, and a first pressure swing adsorption device 10a that prepares nitrogen gas used in the charging device 60. The melting furnace 70 has a shaft 72, a bosh 74 installed at the lower end of the shaft 72, and a furnace bottom 76 installed below the bosh 74. From the shaft 72 to the furnace bottom 76, an upper tuyere 75 for the pyrolysis zone and a lower tuyere 77 for the combustion and melting zone are installed, in order from top to bottom. The upper tuyere 75 and the lower tuyere 77 may each be installed in multiple stages.

[0067] The waste, carbonaceous material, and secondary materials are charged into the melting furnace 70 in the charging device 60 after removing air from the waste, carbonaceous material, and secondary materials using nitrogen gas. Examples of waste include municipal solid waste, industrial waste, processed waste such as incineration ash obtained by drying, incineration, crushing, etc., and landfill waste containing soil and sand excavated after landfill disposal. The secondary materials may contain the basicity adjuster described above. In addition to the basicity adjuster, the secondary materials may contain at least one selected from iron ore, magnesia, periclase, diatomite, jamonite, etc. The use of such secondary materials allows the waste 78 to be sufficiently melted inside the melting furnace 70. Examples of carbonaceous materials that can be used include coal, coke, molded charcoal, woody biomass, etc.

[0068] Oxygen-enriched air is supplied from the lower tuyere 77, and air is supplied as a combustion-supporting gas from the upper tuyere 75. The carbonaceous material charged into the melting furnace 70 is combusted by the oxygen-enriched air supplied from the lower tuyere 77, and functions as a heat source. The waste 78 including secondary materials charged into the melting furnace 70 is heated to, for example, 1600°C or higher by the combustion of the carbonaceous material, and becomes pyrolysis residue 73. The pyrolysis residue 73 is combusted mainly by the air supplied from the upper tuyere 75.

[0069] The combustible matter in the waste 78 and the plastics and biomass contained in the molded basicity adjuster are gasified and rise within the melting furnace 70, then introduced into the combustion chamber via the exhaust gas pipe 62. Meanwhile, the ash turns into molten slag via the pyrolysis residue 73. The lime source and silica source contained in the molded basicity adjuster function as basicity adjusters for the molten slag. The molten slag with its basicity adjusted flows down the carbonaceous material packed layer 71 at the furnace bottom 76 and is discharged from the slag discharge port 79.

[0070] The pyrolysis gas generated in the melting furnace 70 rises up the shaft 72 and is introduced into the combustion chamber through an exhaust gas pipe 62 connected to the bottom of the charging device 60. The combustion exhaust gas is burned as combustible gas, and then the waste heat is recovered in a boiler. The exhaust gas then has its temperature adjusted in a cooling tower, passes through a dust collector and a catalytic reaction tower, and may be discharged from a chimney.

[0071] The first pressure swing adsorption apparatus 10a may be a PSA nitrogen gas purification apparatus (N2-PSA) that purifies nitrogen gas. The first pressure swing adsorption apparatus 10a obtains, for example, high-purity nitrogen gas from air and discharges an off-gas containing nitrogen gas and oxygen gas. As shown in FIG. 3, the first pressure swing adsorption apparatus 10a also has multiple (e.g., two to four) adsorption towers, each containing an adsorbent that adsorbs gases other than nitrogen gas (e.g., oxygen gas). Each adsorption tower may repeatedly perform the following steps: adsorption, depressurization, evacuation, regeneration, and pressurization.

[0072] The nitrogen gas obtained in the first pressure swing adsorption unit 10a may be used in the charging unit 60 to remove and charge air present in the waste, carbonaceous material, and secondary materials. The off-gas generated during the depressurization, evacuation, regeneration, and other processes contains oxygen gas. Hereinafter, in this example, the off-gas containing oxygen gas will be referred to as the "first gas." Similar to the embodiment shown in FIG. 1 , the first gas flows through the flow path 12 and is sequentially introduced into each of the multiple tanks 20. The first gas introduced into the first tank 21 and the second tank is retained and homogenized. In this way, the second gas, whose composition varies less over time than the first gas, is obtained in the first tank 21 and the second tank. Furthermore, the second gas stored in the first tank 21 and the second tank has the same composition.

[0073] The mixer 30 is connected to a flow path 52 for supplying a second gas and a flow path 53 for supplying a third gas. The third gas may be high-purity oxygen gas obtained by a second pressure swing adsorption unit 80. The second pressure swing adsorption unit 80 may be a PSA oxygen gas purifier (O2-PSA) that purifies oxygen gas from air. As shown in FIG. 3, the PSA oxygen gas purifier also has a configuration including multiple (e.g., two to four) adsorption towers, each containing an adsorbent that adsorbs gases other than oxygen gas (such as nitrogen gas). Each adsorption tower may repeatedly perform an adsorption step, a depressurization step, an evacuation step, a regeneration step, and a pressurization step.

[0074] The oxygen gas concentration of the oxygen-enriched air (fourth gas) obtained by mixing the second gas and the third gas in mixer 30 may be, for example, 30 to 80% by volume, or 40 to 70% by volume. The oxygen-enriched air produced in mixer 30 may be mixed with air as necessary and then supplied to melting furnace 70 from lower tuyere 77. By using the first gas generated in first pressure swing adsorption unit 10a to adjust the oxygen-enriched air, the load on second pressure swing adsorption unit 80 can be reduced. Furthermore, since the composition of the oxygen-enriched air obtained in mixer 30 is sufficiently suppressed from fluctuating over time, melting furnace 70 can be operated sufficiently stably.

[0075] A gas homogenization method according to one embodiment includes an introduction step of sequentially introducing a first gas, the composition of which fluctuates over time, into a plurality of tanks (20); an extraction step of extracting a second gas, the second gas having a composition that fluctuates less over time than the first gas, from at least one of the tanks (20); and a mixing step of mixing the second gas with a third gas, the third gas having a composition different from the first and second gases, in a mixer to obtain a fourth gas. This gas homogenization method may be performed in the gas homogenizer 100 of the hydrogen gas production facility (200) shown in FIG. 1, the gas homogenizer 110 of the hydrogen gas production facility (210) shown in FIG. 5, the gas homogenizer 120 of the gasification and melting furnace facility (300) shown in FIG. 7, or a facility other than these. The descriptions of the above-described devices and facilities also apply to the gas homogenization method.

[0076] A method for operating a hydrogen gas production facility according to one embodiment is a method for operating a hydrogen gas production facility 200 (210) including a gas homogenization device 100 (110) and a pressure swing adsorption device 10 shown in FIG. 1 (FIG. 5), and includes a first introduction step of introducing at least a portion of the off-gas containing hydrogen gas derived from the pressure swing adsorption device 10 into the gas homogenization device 100 as a first gas; a second introduction step of introducing a third gas containing hydrogen gas and nitrogen gas into the mixer 30; a third introduction step of introducing a fourth gas containing hydrogen gas and nitrogen gas into the pressure swing adsorption device 10; and a purification step of obtaining hydrogen gas from the fourth gas in the pressure swing adsorption device 10.

[0077] This method for operating a hydrogen gas production facility may be performed in the hydrogen gas production facility 200 shown in Fig. 1, the hydrogen gas production facility 210 shown in Fig. 5, or a hydrogen gas production facility other than these. The explanations for the hydrogen gas production facilities 200 and 210 also apply to the method for operating a hydrogen gas production facility.

[0078] A method for producing hydrogen gas according to one embodiment may be performed using a pressure swing adsorption apparatus 10 shown in Fig. 4. The above description of hydrogen gas production equipment 200 and its operating method also applies to the method for producing hydrogen gas. This hydrogen gas production method includes an adsorption step of introducing a raw material gas containing hydrogen gas and a different component (e.g., nitrogen gas) different from hydrogen gas into an adsorption tower and adsorbing the different component onto an adsorbent in the adsorption tower 10A (10B, 10C, 10D) to obtain a purified gas having a higher hydrogen gas concentration than the raw material gas; a depressurization step of stopping the introduction of the raw material gas into the adsorption tower 10A (10B, 10C, 10D) and lowering the pressure in the adsorption tower 10A (10B, 10C, 10D) to a level lower than that in the adsorption step to discharge the gas remaining in the adsorption tower 10A (10B, 10C, 10D); and a depressurization step of further lowering the pressure in the adsorption tower 10A (10B, 10C, 10D) to a level lower than that in the depressurization step to discharge the gas remaining in the adsorption tower 10A (10B, 10C, 10D). a regeneration step of further reducing the pressure in the adsorption tower 10A (10B, 10C, 10D) to a level lower than that in the depressurization step, and discharging the different components adsorbed to the adsorbent together with the gas remaining in the adsorption tower 10A (10B, 10C, 10D); a pressurization step of pressurizing the adsorption tower 10A (10B, 10C, 10D) by introducing a raw material gas into the adsorption tower 10A (10B, 10C, 10D) following the regeneration step; and a fractionation step of separating a first off-gas discharged from the adsorption tower 10A (10B, 10C, 10D) in the depressurization step and the regeneration step from a second off-gas discharged from the adsorption tower 10A (10B, 10C, 10D) in the depressurization step and the regeneration step, and a second off-gas having a lower average concentration of hydrogen gas than the first off-gas.

[0079] The raw material gas is not limited to the fourth gas, and various gases including hydrogen gas can be used. By repeatedly performing a series of processes in each adsorption tower, high-purity hydrogen gas can be continuously produced while the off-gas can be effectively utilized. The number of adsorption towers is not limited to four. In the fractionation process, the off-gas obtained in the depressurization process, the exhaust process, and the regeneration process may be fractionated into three off-gases with different average hydrogen gas concentrations, or the off-gas obtained in the depressurization process may be fractionated into the off-gas obtained in the exhaust process and the regeneration process. In this way, it is sufficient to obtain multiple off-gases with different average hydrogen gas concentrations.

[0080] A method for operating a gasification and melting furnace facility according to one embodiment is a method for operating a gasification and melting furnace facility 300 including a gas homogenizer 120 shown in FIG. 7 , a melting furnace 70, and a first pressure swing adsorption unit 10a that purifies nitrogen gas used in the charging device 60 of the melting furnace 70. The method includes a first introducing step of introducing at least a portion of the oxygen-containing off-gas derived from the first pressure swing adsorption unit 10a as a first gas into the gas homogenizer 120, a second introducing step of introducing a first oxygen-containing gas containing oxygen as a third gas into the mixer 30, and a third introducing step of introducing a second oxygen-containing gas containing a fourth gas into the melting furnace 70. The third gas (first oxygen-containing gas) may be a gas obtained in the second pressure swing adsorption unit 80. The second oxygen-containing gas may be oxygen-enriched air obtained by mixing the third gas with air.

[0081] This method of operating a gasification and melting furnace facility may be performed in the gasification and melting furnace facility 300 shown in Figure 7 or in a separate gasification and melting furnace facility. The explanation of the gasification and melting furnace facility 300 also applies to the method of operating a gasification and melting furnace facility.

[0082] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. The present disclosure includes the following embodiments.

[0083] [1] A plurality of tanks into which a first gas having a composition that varies over time is sequentially introduced; a flow path through which a second gas flows, the second gas being drawn from at least one of the plurality of tanks and having a composition that varies less over time than the first gas; a mixer that mixes the second gas with a third gas having a composition different from that of the first gas and the second gas to deliver a fourth gas. [2] The gas homogenizing apparatus according to [1], wherein the composition of the first gas varies periodically. [3] The gas homogenizer according to [1] or [2], wherein the first gas comprises at least a portion of the off-gas discharged from the pressure swing adsorption device. [4] The flow path of the off-gas discharged from the adsorption tower of the pressure swing adsorption device is branched into multiple paths, The gas homogenization apparatus according to [3], wherein the off-gas is fractionated into a plurality of off-gases having different average hydrogen concentrations, and the fractionated off-gases are sequentially introduced into the plurality of tanks as the first gas. [5] A switching unit is provided to switch the tank into which the first gas is introduced so that the first gas is introduced into the plurality of tanks sequentially, The gas homogenizing device according to any one of [1] to [4], wherein the switching unit switches the tanks for each cycle of composition fluctuation of the first gas. [6] A switching unit is provided to switch the tank into which the first gas is introduced so that the first gas is introduced sequentially into the plurality of tanks, The gas homogenizing device according to any one of [1] to [5], wherein the switching unit switches between the tanks at a cycle shorter than the cycle of composition fluctuation of the first gas. [7] A gas homogenization device described in any one of [1] to [6], wherein the total number of the plurality of tanks is greater than the number of tanks into which the first gas is introduced per one cycle of composition fluctuation of the first gas. [8] A hydrogen gas production facility comprising the gas homogenization apparatus according to any one of [1] to [7] above and a pressure swing adsorption apparatus for purifying hydrogen gas, at least a portion of the off-gas containing hydrogen gas discharged from the pressure swing adsorption device is introduced into the gas homogenizer as the first gas; The third gas containing hydrogen gas and nitrogen gas is introduced into the mixer; A hydrogen gas production facility, wherein a gas containing the fourth gas is introduced into the pressure swing adsorption unit. [9] The hydrogen gas production facility according to [8], wherein the average concentration of hydrogen gas in the off-gas introduced into the gas homogenizer as the first gas is 40% by volume or more.

[10] A gasification and melting furnace facility comprising: the gas homogenization apparatus according to any one of [1] to [9] above; a melting furnace; a charging device provided above the melting furnace; and a first pressure swing adsorption device for purifying nitrogen gas used in the charging device, at least a portion of the oxygen-containing off-gas discharged from the first pressure swing adsorption unit is introduced into the gas homogenizer as the first gas; a first oxygen-containing gas containing oxygen as the third gas is introduced into the mixer; A gasification and melting furnace facility, wherein a second oxygen-containing gas containing the fourth gas is introduced into the melting furnace.

[11] The gasification and melting furnace equipment described in

[10] further comprises a second pressure swing adsorption device for obtaining the first oxygen-containing gas having a higher oxygen gas concentration than the air as the third gas from air.

[12] an introduction step of sequentially introducing a first gas whose composition varies over time into a plurality of tanks; a discharge step of discharging a second gas having a composition that varies less over time than the first gas from at least one of the plurality of tanks; a mixing step of mixing the second gas with a third gas having a composition different from that of the first gas and the second gas in a mixer to obtain a fourth gas.

[13] A flow path leading from an adsorption tower of a pressure swing adsorption device is branched into multiple branches, and a fractionation step is provided in which the off-gas led from the adsorption tower is fractionated into multiple branches; The gas homogenization method according to

[12] , wherein a portion of the separated off-gas is introduced as the first gas into the plurality of tanks sequentially.

[14] A method for operating a hydrogen gas production facility including the gas homogenization apparatus according to any one of [1] to [9] above and a pressure swing adsorption apparatus for purifying hydrogen gas, comprising: a first introducing step of introducing at least a portion of an off-gas containing hydrogen gas discharged from the pressure swing adsorption device into the gas homogenizer as the first gas; a second introducing step of introducing the third gas containing hydrogen gas and nitrogen gas into the mixer; a third introducing step of introducing the fourth gas into the pressure swing adsorption device; and a purification step of obtaining hydrogen gas from the fourth gas in the pressure swing adsorption device.

[15] A method for operating a gasification and melting furnace facility including the gas homogenization apparatus according to any one of [1] to [9] above, a melting furnace, and a first pressure swing adsorption device for purifying nitrogen gas used in a charging device of the melting furnace, comprising: a first introducing step of introducing at least a portion of the oxygen-containing off-gas delivered from the first pressure swing adsorption unit into the gas homogenizer as the first gas; a second introduction step of introducing a first oxygen-containing gas containing oxygen as the third gas into the mixer; a third introducing step of introducing a second oxygen-containing gas containing the fourth gas into the melting furnace.

[16] A method for producing hydrogen gas using a hydrogen gas production facility including: a plurality of tanks into which a first gas containing hydrogen gas and having a composition that varies over time is sequentially introduced; a flow path through which a second gas that is extracted from at least one of the plurality of tanks and has a reduced range of variation in composition over time compared to the first gas flows; a mixer that mixes the second gas with a third gas that has a composition different from the first gas and the second gas and extracts a fourth gas; and a pressure swing adsorption apparatus having an adsorption tower, an adsorption step of introducing the fourth gas containing hydrogen gas and a different component different from the hydrogen gas into the adsorption tower, and adsorbing the different component onto an adsorbent in the adsorption tower to obtain hydrogen gas; a depressurization step of stopping the introduction of the fourth gas into the adsorption tower, reducing the pressure in the adsorption tower to a level lower than that in the adsorption step, and discharging the gas remaining in the adsorption tower; an exhaust step of further reducing the pressure in the adsorption tower to a level lower than that in the depressurization step to discharge gas remaining in the adsorption tower; a regeneration step of discharging the different components adsorbed by the adsorbent together with the gas remaining in the adsorption tower; a pressurizing step of pressurizing the inside of the adsorption tower by introducing the fourth gas into the adsorption tower after the regeneration step, A method for producing hydrogen gas, comprising a fractionation step of fractionating the off-gas discharged in the depressurization step, the exhaust step, and the regeneration step to obtain a plurality of off-gases having different average concentrations of hydrogen gas.

[17] The method for producing hydrogen gas according to

[17] , wherein the fractionation step separates a first off-gas discharged from the adsorption tower in the depressurization step and the regeneration step from a second off-gas discharged from the adsorption tower in the exhaust step and having a lower average concentration of hydrogen gas than the first off-gas.

[18] The method for producing hydrogen gas according to

[16] or

[17] , wherein the fourth gas contains hydrogen gas obtained by decomposing ammonia.

[19] A method for making iron, in which the hydrogen gas and / or the plurality of off-gases obtained by the method for producing hydrogen gas according to any one of the above items

[16] to

[18] are used in a steelmaking process.

[20] A method for making iron, in which the hydrogen gas and / or the plurality of off-gases obtained by the method for producing hydrogen gas according to any one of the above items

[16] to

[18] are introduced into a blast furnace.

[21] A heat treatment method, comprising introducing the hydrogen gas and / or the plurality of off-gases obtained by the method for producing hydrogen gas according to any one of the above

[16] to

[18] into a heating furnace.

[22] A method for producing iron ore, comprising introducing the hydrogen gas and / or the plurality of off-gases obtained by the method for producing hydrogen gas according to any one of

[16] to

[18] above into a direct reduction furnace for iron ore. [Example]

[0084] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0085] Example 1 As shown in FIG. 8 , the composition (volume ratio of oxygen gas and nitrogen gas) of the first gas (off-gas) obtained in the first pressure swing adsorption unit 10a fluctuates periodically. Simulation results of the oxygen gas concentration and nitrogen gas concentration in the mixer 30 when this first gas is supplied to the gas homogenizer 120 of the gasification and melting furnace facility 300 shown in FIG. 7 are shown in FIGS. 9(A) and 9(B), respectively. In this simulation, the mixer 30 had a cylindrical shape with an inner diameter of 1200 mm and a length of 4200 mm, and contained a total of 13 alternating disk-shaped (diameter: 1000 mm) and ring-shaped baffles (through-hole diameter: 350 mm). As shown in FIG. 8 , the first gas, whose composition fluctuates, was sequentially introduced into the first tank 21 and the second tank 22, and a second gas with a composition fluctuation range smaller than that of the first gas was obtained. The mixer 30 was charged with a third gas of oxygen gas:nitrogen gas=90% by volume:10% by volume at 1000 Nm 3 / h, and the second gas obtained by homogenization in each tank was 790 Nm 3 / h.

[0086] The horizontal axes in Figures 9(A) and 9(B) represent the 14 regions (stages) in the mixer 30, which are partitioned by 13 baffles and numbered in order from the upstream side. As shown in Figures 9(A) and 9(B), the influence of the composition fluctuation of the first gas shown in Figure 8 was eliminated in the mixer 30, and a homogeneous fourth gas could be obtained. The composition of the fourth gas became constant from the third stage onwards in the mixer 30.

[0087] (Comparative Example 1) A simulation was performed to measure the oxygen gas concentration and nitrogen gas concentration at the outlet of the mixer 30 when a first gas whose composition fluctuated as shown in FIG. 8 was directly introduced into the mixer 30 without using multiple tanks 20. The conditions were the same as in Example 1 except that multiple tanks 20 were not used. As a result, as shown in FIGS. 10(A) and 10(B), the composition of the fourth gas fluctuated periodically, and was affected by the composition fluctuations of the first gas. This confirmed that it is difficult to suppress composition fluctuations using the mixer 30 alone.

[0088] Example 2 A simulation was conducted to determine the extent to which the load on second pressure swing adsorption unit 80 would be reduced when gas homogenization unit 120 was installed in gasification and melting furnace facility 300, as shown in Figure 7. As shown in Figure 11, first gas (off-gas with an average oxygen gas concentration of 33% by volume) was discharged from first pressure swing adsorption unit 10a at a rate of 790 Nm3. 3 Air was supplied to the second pressure swing adsorption device 80, and a third gas with an oxygen gas concentration of 90% by volume was obtained. The fourth gas discharged from the mixer 30 was pressurized by a blower and then mixed with air to become oxygen-enriched air with an oxygen gas concentration of 38% by volume, which was then discharged from the lower tuyeres to the melting furnace 70 at a rate of 4000 Nm 3 In this case, the amount of air introduced into second pressure swing adsorption unit 80 was 865 Nm 3 / h.

[0089] (Comparative Example 2) A simulation was conducted to determine the amount of air introduced into second pressure swing adsorption apparatus 80 when the off-gas from first pressure swing adsorption apparatus 10a was released without recovery, without using multiple tanks 20 and mixers 30. In order to make the flow rate and oxygen gas concentration of the oxygen-enriched air introduced into melting furnace 70 from the lower tuyere the same as those in Example 2, as shown in FIG. 12 , air was introduced into second pressure swing adsorption apparatus 80 at a rate of 1000 Nm 3 It was necessary to introduce the gas at a flow rate of 1000 kJ / h.

[0090] The results of Example 2 and Comparative Example 2 confirmed that by recovering off-gas generated from first pressure swing adsorption unit 10a with an average oxygen gas concentration of 33 volume %, it is possible to sufficiently reduce the load on second pressure swing adsorption unit 80. Note that the "%" shown in Figures 11 and 12 is a volume-based value. [Explanation of symbols]

[0091] 10...pressure swing adsorption device, 10a...first pressure swing adsorption device, 10A...first adsorption tower, 10B...second adsorption tower, 10C...third adsorption tower, 10D...fourth adsorption tower, 12, 13, 14, 44, 51, 52, 53, 54...flow path, 20, 20A...multiple tanks, 21...first tank, 22...second tank, 23...third tank, 24...fourth tank, 25...fifth tank, 26...sixth tank, 27...seventh tank, 30...mixer, 30A...premixer, 31, 3 2, 33, 35, 36, 37...baffle plates, 38, 39...vessel body, 40...compressor, 60...charging device, 62...exhaust gas pipe, 70...melting furnace, 71...carbonaceous material packed bed, 72...shaft portion, 73...pyrolysis residue, 74...bosom portion, 75...upper tuyere, 76...furnace bottom portion, 77...lower tuyere, 78...waste, 79...slag discharge port, 80...second pressure swing adsorption device, 100, 110, 120...gas homogenization device, 200, 210...hydrogen gas production equipment, 300...gasification melting furnace equipment.

Claims

1. a pressure swing adsorption unit for purifying the gas; a plurality of tanks into which a first gas having a composition that varies over time is sequentially introduced; the first gas comprises at least a portion of the off-gas discharged from the pressure swing adsorption device; the off-gas is fractionated into a first off-gas and a second off-gas having an average hydrogen concentration lower than that of the first off-gas, and the fractionated first off-gas is sequentially introduced into the plurality of tanks as the first gas.

2. a flow path of the off-gas discharged from the pressure swing adsorption device branches into a first off-gas flow path and a second off-gas flow path; The gas homogenizing apparatus according to claim 1 , wherein the separated first off-gas flows through a first off-gas passage and is sequentially introduced into the plurality of tanks.

3. 3. The gas homogenizing apparatus according to claim 2, wherein the separated second off-gas flows through a second off-gas passage and is introduced into a treatment facility.

4. the first off-gas flowing through the first off-gas passage is used for a first purpose, The gas homogenizing device according to claim 3 , wherein the second off-gas flowing through the second off-gas passage is used for a second purpose.

5. 3. The gas homogenizing apparatus of claim 1, wherein the composition of the first gas varies periodically.

6. a switching unit that switches the tank into which the first gas is introduced so that the first gas is introduced into the plurality of tanks sequentially; The gas homogenizing device according to claim 1 or 2, wherein the switching unit switches the tanks for each cycle of composition fluctuation of the first gas.

7. a switching unit that switches the tank into which the first gas is introduced so that the first gas is introduced into the plurality of tanks sequentially; The gas homogenizing device according to claim 1 or 2, wherein the switching unit switches the tanks at a cycle shorter than a cycle of fluctuation in the composition of the first gas.

8. 3. The gas homogenizing apparatus according to claim 1, wherein the total number of the plurality of tanks is greater than the number of tanks into which the first gas is introduced per one cycle of composition fluctuation of the first gas.

9. A hydrogen gas production facility equipped with the gas homogenization device according to claim 1 or 2, at least a portion of the off-gas containing hydrogen gas discharged from the pressure swing adsorption unit is introduced into the gas homogenizer as the first gas; a mixer that mixes a second gas that is delivered from at least one of the plurality of tanks and has a smaller fluctuation range in composition over time than the first gas, with a third gas that includes hydrogen gas and nitrogen gas, and delivers a fourth gas; A hydrogen gas production facility, wherein a gas containing the fourth gas is introduced into the pressure swing adsorption unit.

10. 10. The hydrogen gas production facility according to claim 9, wherein the average concentration of hydrogen gas in the off-gas introduced into the gas homogenizer as the first gas is 40% by volume or more.

11. 3. A gasification and melting furnace facility comprising: the gas homogenization apparatus according to claim 1 or 2; a melting furnace; a charging device provided above the melting furnace; and a first pressure swing adsorption device that purifies nitrogen gas used in the charging device, the first pressure swing adsorption device is the pressure swing adsorption device; at least a portion of the oxygen-containing off-gas discharged from the first pressure swing adsorption unit is introduced into the gas homogenizer as the first gas; a first oxygen-containing gas containing oxygen as a third gas, and a second gas derived from at least one of the plurality of tanks and having a composition fluctuation range over time reduced compared to the first gas, are introduced into a mixer; The gasification and melting furnace facility, wherein the second oxygen-containing gas discharged from the mixer is introduced into the melting furnace.

12. The gasification and melting furnace facility according to claim 11, further comprising a second pressure swing adsorption device that obtains, as the third gas, the first oxygen-containing gas having a higher oxygen gas concentration than the air from air.

13. an introducing step of sequentially introducing a first gas whose composition varies over time into a plurality of tanks; the first gas comprises at least a portion of an off-gas derived from a pressure swing adsorption apparatus that purifies a gas; a first off-gas and a second off-gas having an average hydrogen concentration lower than that of the first off-gas, and the first off-gas is introduced sequentially into the tanks as the first gas.

14. a flow path of the off-gas discharged from the pressure swing device branches into a first flow path and a second flow path, The gas homogenization method according to claim 13, wherein the separated first off-gas flows through a first flow path and is sequentially introduced into the plurality of tanks.

15. 3. A method for operating a hydrogen gas production facility including the gas homogenization apparatus according to claim 1 or 2 and a pressure swing adsorption apparatus for purifying hydrogen gas, comprising: a first introducing step of introducing at least a portion of an off-gas containing hydrogen gas discharged from the pressure swing adsorption device into the gas homogenizer as the first gas; a second introduction step of mixing a second gas, which is delivered from at least one of the plurality of tanks and has a smaller fluctuation range in composition over time than the first gas, with a third gas containing hydrogen gas and nitrogen gas, and introducing the mixture into a mixer that delivers a fourth gas; a third introducing step of introducing the fourth gas into the pressure swing adsorption device; and a purification step of obtaining hydrogen gas from the fourth gas in the pressure swing adsorption device.

16. 3. A method for operating a gasification and melting furnace facility including the gas homogenization apparatus according to claim 1 or 2, a melting furnace, and a first pressure swing adsorption device for purifying nitrogen gas used in a charging device of the melting furnace, comprising: a first introducing step of introducing at least a portion of the oxygen-containing off-gas discharged from the first pressure swing adsorption unit into the gas homogenizer as the first gas; a second introduction step of mixing a second gas, which is delivered from at least one of the plurality of tanks and has a reduced fluctuation range in composition over time compared to the first gas, with a third gas, which is a first oxygen-containing gas containing oxygen, and introducing the mixture into a mixer from which a fourth gas is delivered; a third introducing step of introducing a second oxygen-containing gas containing the fourth gas into the melting furnace.

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