Gas Separation Method

Abstract

Provided is a gas separation method, whereby it becomes possible to separate gases respectively suitable for a plurality of gas utilization facilities from a raw material gas and supply the gases to the gas utilization facilities by a pressure swing adsorption method. The gas separation method according to the present invention comprises: a desired gas component adsorption step for introducing a raw material gas to an adsorption column filled with an adsorbent to cause a desired gas component to be adsorbed onto the adsorbent; a desired gas component detachment step for detaching the desired gas component adsorbed on the adsorbent in the desired gas component adsorption step and discharging a desorbed gas containing the desired gas component from the adsorption column; and a detached gas supply step for supplying the detached gas discharged from the adsorption column in the desired gas component detachment step to at least two different gas utilization facilities. The gas separation method is characterized in that the desired gas component detachment step includes a detached gas utilization facility switching step for switching between the gas utilization facilities for the detached gas in the detached gas supply step.

Description

Gas Separation Method

[0001] The present invention relates to a gas separation method.

[0002] Conventionally, pressure swing adsorption (PSA) has been used as a method for separating predetermined gas components contained in a raw gas (see, for example, Patent Document 1). The PSA is a separation method that utilizes the fact that the amount of gas components adsorbed onto an adsorbent varies depending on the gas type and its partial pressure. The PSA typically includes a step of adsorbing the gas components onto an adsorbent (adsorption step), a step of supplying a portion of the desorbed gas desorbed in another adsorption tower as a cleaning gas in order to increase the adsorption rate of the gas components onto the adsorbent (cleaning step), and a step of desorbing the adsorbed gas components from the adsorbent to recover the gas (desorption step).

[0003] The PSA method is applied in a variety of fields, but is often used as a method for producing highly concentrated gas by adsorbing one component contained in a raw material gas. There are two types of PSA methods: a pressurized method that uses a pressure difference between pressurized and atmospheric pressure, and a suction method that uses a pressure difference between atmospheric pressure (or slightly pressurized) and reduced pressure; the latter is sometimes called a VSA method (Vacuum Swing Adsorption).

[0004] In recent years, carbon dioxide (CO ) emitted from steelmaking processes and other processes has ２ ) to produce useful chemicals such as methanol ２ The Carbon dioxide Capture and Utilization (CCU) process is being considered. In a reaction process such as CCU, raw gas does not need to be of high purity, making it possible to reduce the cost of gas separation equipment.

[0005] As a gas separation facility suitable for the above-mentioned CCU, the applicant has proposed in Patent Document 2 a method of separating gases by utilizing the difference in gas desorption time, taking advantage of the characteristic that the gas desorption time from an adsorbent differs depending on the type of adsorbed gas. ２ , carbon monoxide (CO), nitrogen (N ２) containing CO ２ and CO and N, which have weak adsorption power ２ Here, the separated CO ２ To be precise, some CO and N ２ Gas containing impurity gases such as CO ２ However, for the sake of simplicity, we will refer to CO ２ It is called.

[0006] JP 06-144818 A JP 2018-114464 A

[0007] The simple gas separation method described in Patent Document 2 can reduce the production costs of CCU chemicals. However, the gas separated by the method described in Patent Document 2 may contain a large amount of impurities depending on the operating method. This may affect the catalytic performance of the reactor in the CCU process.

[0008] The reactors used in CCU use various catalysts depending on the target reaction products, but the catalyst performance is affected not only by reaction conditions such as temperature and pressure, but also by the composition of the raw material gas. ２ When using a catalyst that is easily deactivated by impurity gas components other than CO, ２ On the other hand, impurity gas components that do not affect the catalytic performance can be supplied to the reactor as they are, so high-purity CO ２ is not necessary.

[0009] In this way, the raw material gas CO required for each catalyst in the reactor ２ If the purity of CO is different, ２ Depending on the purity, appropriate CO ２ Separation equipment must be selected. For example, high purity CO ２ When high purity CO is required, a method such as chemical absorption can be used. ２ CO ２ Separation equipment is preferred. ２ When CO is not required, it can be easily obtained by using, for example, the PSA method described above. ２Separation can be performed.

[0010] On the other hand, the CO ２ When installing separation equipment, various disadvantages arise, such as increased construction costs and increased operating personnel due to the installation of multiple facilities. ２ Since the production volume of each reactor is limited by the processing capacity of the separation equipment, it is not possible to flexibly adjust the balance of production volumes between the reactors.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a gas separation method that can separate suitable gases from a raw gas and supply them to a plurality of gas utilization facilities using a pressure swing adsorption method.

[0012] The present invention, which solves the above-mentioned problems, is as follows: [1] A gas separation method for adsorbing and separating a target gas component from a source gas containing two or more gas components by pressure swing adsorption, comprising: a target gas component adsorption step of introducing the source gas into an adsorption tower filled with an adsorbent and causing the target gas component to be adsorbed by the adsorbent, a target gas component desorption step of desorbing the target gas component adsorbed by the adsorbent in the target gas component adsorption step and discharging a desorbed gas containing the target gas component from the adsorption tower, and a desorbed gas supply step of supplying the desorbed gas discharged from the adsorption tower in the target gas component desorption step to two or more different gas utilization facilities, wherein the target gas component desorption step includes a desorbed gas utilization facility switching step of switching the supply destination of the desorbed gas to the gas utilization facility in the desorbed gas supply step.

[0013] [2] The gas separation method according to [1], wherein the raw material gas contains at least carbon dioxide and carbon monoxide.

[0014] [3] The gas separation method according to [1] or [2], wherein the raw material gas is an exhaust gas discharged from a reduction furnace.

[0015] [4] The gas separation method according to any one of [1] to [3], characterized in that the switching of the supply destination to the gas utilization facility in the desorption gas utilization facility switching process is carried out at the boundary between the multiple time periods that the desorption process is divided into multiple time periods.

[0016] [5] The gas separation method according to any one of [1] to [4], further comprising, in a stage preceding the desorption gas supply step, either one or both of a desulfurization step for removing sulfur from the raw material gas or the desorption gas, and a water-gas shift reaction step for producing carbon dioxide from carbon monoxide and water contained in the raw material gas or the desorption gas.

[0017] [6] The gas separation method according to any one of [1] to [5], wherein the target gas component adsorption process further includes an adsorption off-gas supply process for supplying an adsorption off-gas containing non-adsorbed gas components that were not adsorbed by the adsorbent in the target gas component adsorption process to one of the two or more different gas utilization facilities.

[0018] [7] The target gas component adsorption process includes an adsorption off-gas utilization equipment switching process for switching the supply destination of the adsorption off-gas to the gas utilization equipment based on the concentration of the target gas component in the adsorption off-gas. The gas separation method described in [6].

[0019] [8] The gas separation method according to any one of [1] to [7], further comprising a gas mixing step of mixing the desorbed gases having different concentrations of the target gas component discharged from the adsorption tower, at a subsequent stage of the target gas component desorption step and a prior stage of the desorption gas supply step.

[0020] [9] The gas separation method according to any one of [1] to [8], wherein one of the two or more gas utilization facilities is a methanol synthesis reactor.

[0021]

[10] The gas separation method according to any one of [1] to [9], wherein one of the two or more gas utilization facilities is a methane synthesis reactor.

[0022]

[11] One of the two or more gas utilization facilities is CO２ The gas separation method according to any one of [1] to [8], characterized in that it is a liquefaction facility.

[0023]

[12] The gas separation method according to

[10] citing [2] or [3] or

[11] citing [2] or [3], characterized in that a product of the gas utilization facility is supplied as a reducing agent in the reduction furnace.

[0024] According to the present invention, suitable gases can be separated from a raw gas by pressure swing adsorption and supplied to a plurality of gas utilization facilities.

[0025] 1 is a flow chart of a gas separation method according to the present invention.

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A gas separation method according to the present invention is a gas separation method for adsorbing and separating a target gas component from a feed gas containing two or more gas components by pressure swing adsorption. The gas separation method includes a target gas component adsorption step of introducing the feed gas into an adsorption tower filled with an adsorbent and adsorbing the target gas component onto the adsorbent, a target gas component desorption step of desorbing the target gas component adsorbed onto the adsorbent in the target gas component adsorption step and discharging a desorbed gas containing the target gas component from the adsorption tower, and a desorbed gas supply step of supplying the desorbed gas discharged from the adsorption tower in the target gas component desorption step to two or more different gas utilization facilities. Here, the target gas component desorption step is characterized by including a desorbed gas utilization facility switching step of switching the supply destination of the desorbed gas to the gas utilization facility in the desorbed gas supply step.

[0027] 1 shows a flowchart of the gas separation method according to the present invention. First, in step S1, a raw gas is introduced into an adsorption tower filled with an adsorbent, and a target gas component is adsorbed onto the adsorbent (target gas component adsorption step).

[0028] The raw material gas is not particularly limited as long as it contains two or more gas components, but it is preferable that the raw material gas contains at least CO ２ and CO. ２Although CO and CO can contribute to global warming if released into the atmosphere, they can be effectively used as raw materials for synthesizing fuels such as methane and methanol, and as a reducing agent in a reduction furnace. CO can also be used as a fuel gas because of its high calorific value. Therefore, the raw material gas should contain at least CO ２ and CO.

[0029] These CO ２ As the raw material gas containing CO, a by-product gas generated in a steelworks can be used. As the by-product gas, an exhaust gas discharged from a reduction furnace such as a blast furnace or a shaft furnace can be used. In particular, the blast furnace gas discharged from a blast furnace contains CO. ２ The raw material gas not only contains a large amount of CO, but also contains CO. When the raw material gas contains CO, there is a concern that catalyst deterioration due to carbon deposition caused by CO may occur depending on the catalyst used in the gas utilization equipment that supplies the raw material gas in the desorption gas supply step described below. However, in the present invention, the CO content of the desorption gas supplied to such equipment can be controlled, so that blast furnace gas can be used as the raw material gas without any problems.

[0030] The above-described raw gas is introduced into an adsorption tower filled with an adsorbent, and the target gas component is adsorbed by the adsorbent. The adsorbent filled in the adsorption tower can be appropriately selected depending on the target gas component to be adsorbed by the adsorbent. The target gas component is not particularly limited, and can be, for example, CO ２ The target gas component can be CO. ２ In this case, 13X zeolite or the like can be suitably used as the adsorbent.

[0031] Next, in step S2, the target gas component adsorbed to the adsorbent in step S1 is desorbed, and the desorbed gas containing the target gas component is discharged from the adsorption tower (target gas component desorption step). The desorption of the target gas component from the adsorbent and the discharge from the adsorption tower can be performed by connecting a vacuum pump to the adsorption tower.

[0032] In the present invention, the desorption process is divided into a plurality of time periods by utilizing the change in the composition of the desorbed gas (concentration of the target gas component) over time, and the desorbed gas is discharged separately for each time period. ２ The 13X zeolite used as an adsorbent for ２ For gas components with low adsorption power such as CO, the adsorption characteristics are linear with respect to pressure. ２ For gas components with a strong adsorptive power such as those mentioned above, the amount of adsorption is large and the adsorption characteristics are nonlinear with respect to pressure.

[0033] When an adsorbent having different adsorption and desorption characteristics depending on the pressure is used, the timing at which the gas components are desorbed varies depending on the gas component in the desorption step. Specifically, gas components having linear adsorption characteristics relative to pressure (e.g., CO, N ２ ) are desorbed during the process of decompression from a high pressure state. On the other hand, gas components that have nonlinear adsorption characteristics with respect to pressure (e.g., CO ２ ) hardly desorbs under high pressure conditions, but desorbs rapidly when the pressure is reduced to a low level.

[0034] Depending on the difference in desorption timing of such gas components, for example, desorbed gas containing a large amount of impurity gas components at the beginning of the desorption process is supplied to a gas utilization facility where the impurity content of the raw material gas is acceptable. In contrast, desorbed gas containing a small amount of impurity gas components at the later stage of the desorption process is supplied to another gas utilization facility where a high-purity raw material gas is required. The amount of desorbed gas supplied to both of these gas utilization facilities and the concentration of the target gas component in the desorbed gas can be easily adjusted by changing the length of the time periods divided in the desorption process.

[0035] Then, in step S21, the supply destination of the desorbed gas to the gas utilization facility in the desorption gas supply process performed in step S3 (described later) is switched (desorption gas utilization facility switching process). The desorption process is divided into multiple time periods, and the switching can be performed at the boundary between the multiple divided time periods. This allows the desorbed gas to be supplied to the appropriate gas utilization facility based on its composition (concentration of the target gas component).

[0036] Subsequently, in step S3, the desorbed gas discharged from the adsorption tower in step S2 is supplied to two or more different gas utilization facilities (desorbed gas supply step), whereby the desorbed gas is supplied to an appropriate gas utilization facility based on its composition (concentration of the target gas component).

[0037] Here, "gas utilization equipment" refers to equipment such as a reactor, reformer, or condenser that chemically or physically changes the desorbed gas or adsorbed off-gas to obtain a target substance. Examples of the reactor include a methanol synthesis reactor and a methane synthesis reactor. Examples of the reformer include a water-gas shift reformer and a methane and CO ２ Furthermore, the condenser may be a dry reforming facility that reacts CO ２ Examples include liquefaction facilities and gas cryogenic separation facilities.

[0038] Among the above, it is preferable that one of the two or more different gas utilization facilities is a methanol synthesis reactor. Methanol can be used as a fuel, and CO ２ and H ２ or CO and H ２ It can be produced by the reaction of CO with ２ + 3H ２ → CH ３ OH + H ２ O (1) CO + 2H ２ → CH ３ OH (2)

[0039] The Cu-Zn catalysts generally used in methanol synthesis are less susceptible to deterioration of catalytic performance due to carbon deposition even when using feed gases containing CO. In addition, feed gases containing a small amount of CO tend to have a higher CO ２ The side reaction of converting CO to CO is suppressed, ２ In this way, when the gas utilization facility is a methanol synthesis reactor, the yield of the reaction of converting CO ２Therefore, the desorbed gas obtained during the middle period of the desorption step, when the CO concentration is relatively high, can be supplied to the methanol synthesizer, and the control of the desorbed gas concentration according to the present invention can be effectively utilized.

[0040] It is also preferable that one of the two or more different gas utilization facilities is a methane synthesis reactor. Methane can be used not only as a fuel but also as a reducing agent for reducing oxides in a reduction furnace. Methane can be used to reduce CO ２ and H ２ or CO and H ２ It can be produced by the reaction of CO with ２ + 4H ２ → CH ４ + 2H ２ O (3) CO + 3H ２ → CH ４ + H ２ O (4)

[0041] CO ２ The Ni catalyst used in methane synthesis from CO may experience deterioration of catalytic performance due to carbon deposition when a raw gas containing CO is used. ２ The desorbed gas obtained during the latter period of the desorption step in which is desorbed is supplied to the methanol synthesizer.

[0042] Furthermore, one of two or more different gas utilization facilities may be ２ It is preferable to use a liquefaction facility. ２ When the adsorbent is a zeolite, most of the gas components desorbed in the later stage of the desorption process are CO, which has a strong adsorption force to the adsorbent. ２ and the desorbed gas is high purity CO ２ Therefore, the desorbed gas discharged in the later stage of the desorption process is CO ２ CO storage (CCS) and other purposes ２ It can be fed to a liquefaction facility.

[0043] In addition, the raw material gas contains at least CO ２ In the case where the product of the gas utilization facility is a gas containing CO and CO, or an exhaust gas discharged from a reducing furnace, the product can be supplied as a reducing agent to the reducing furnace. The product of the gas utilization facility is not limited to the above-mentioned methanol, and is not limited to a specific substance as long as it has reducing properties for the reducing furnace feedstock, such as iron ore. Similarly, the physical properties, such as gas or liquid, are not limited.

[0044] For example, when the gas utilization facility is a methane synthesis reactor, the generated methane has a reducing effect on oxides such as iron ore, and can therefore be used as a reducing agent in a reduction furnace. ２ If CO ２ It is possible to construct a carbon recycling reduction process that converts carbon dioxide into methane and recycles C. Furthermore, although the methane synthesis reaction is an exothermic reaction, the high-temperature methane produced can be used as a reducing agent in the reduction furnace, thereby making it possible to effectively utilize the reaction heat of methane synthesis.

[0045] In this way, by the PSA method, suitable gases can be separated from the raw material gas and supplied to a plurality of gas utilization facilities.

[0046] In the present invention, a desulfurization step for removing sulfur from the raw material gas or the desorbed gas is carried out before the desorption gas supply step, and a desulfurization step for removing CO and water (H ２ O) to CO ２ The process may further comprise either or both of a water gas shift reaction step to produce

[0047] That is, if the catalytic performance of the gas utilization facility is susceptible to deterioration due to sulfur, it is preferable to remove sulfur contained in the gas in a desulfurization facility before supplying the desorbed gas to the gas utilization facility (desulfurization step). In this way, whether or not to perform the desulfurization step can be selected depending on the performance of the catalyst, etc. used in the gas utilization facility.

[0048] When the desulfurization process is performed, the stage at which it is performed is not particularly limited as long as it is performed before the desorption gas supply process in which the desorption gas is supplied to the gas utilization equipment. For example, the desulfurization process can be performed by installing a desulfurization equipment before any one of the gas utilization equipment. Alternatively, a desulfurization equipment can be installed before the PSA equipment to remove sulfur from the raw material gas, and then the desulfurized raw material gas can be supplied to the PSA equipment, so that the desulfurized desorbed gas can be supplied to all of the gas utilization equipment.

[0049] The water gas shift reaction process is carried out by reacting CO and H ２ The reaction of the reaction gas with O represented by the following formula (5) is carried out, and the CO concentration and CO ２ The balance between CO + H concentration can be adjusted. ２ O → CO ２ + H ２ (5)

[0050] For example, when the allowable CO concentration is low in gas-using equipment, ２ When the required concentration is high, the requirements of the gas utilization facility can be met by carrying out a water gas shift reaction step as a pretreatment step for the desorption gas supply step.

[0051] Both the desulfurization step and the water-gas shift reaction step can be carried out as appropriate depending on the specifications of the gas utilization facility. Furthermore, both the desulfurization step and the water-gas shift reaction step can be carried out continuously before the desorption gas supply step. In this case, it is preferable to carry out the water-gas shift reaction step after the desulfurization step. By carrying out both steps in this order, sulfur in the gas is removed before the gas is supplied to the facility where the water-gas shift reaction is carried out. Therefore, the catalyst in the facility where the water-gas shift reaction step is carried out does not come into contact with sulfur, which is more preferable because it slows down the catalyst degradation rate.

[0052] It is also preferable to further include a gas mixing step, following the target gas component desorption step and preceding the desorption gas supply step, in which desorption gases with different concentrations of target gas components discharged from the adsorption tower are mixed. That is, if the desorption gases discharged in separate time periods during the desorption step are directly supplied to the gas utilization facility, fluctuations in the composition of the desorption gases directly lead to fluctuations in the composition of the feed gas of the gas utilization facility, which may affect the production efficiency of the gas utilization facility. Therefore, it is preferable to provide a gas mixing facility such as a tank upstream of the gas utilization facility, collect and thoroughly mix the desorption gases discharged over a predetermined period of time to equalize the composition of the desorption gases, thereby reducing the impact of composition fluctuations before supplying them to the gas utilization facility. This reduces the impact on the production efficiency of the gas utilization facility.

[0053] In the desorption gas supply step, the gas supplied to the gas utilization facility is the desorbed gas obtained in the target gas component desorption step. In addition, in the present invention, an adsorption off-gas containing non-adsorbed gas components that were not adsorbed by the adsorbent in the target gas component adsorption step can be supplied to the gas utilization facility (adsorption off-gas supply step). That is, in the gas utilization facility, a main reaction gas (e.g., CO ２ In the case where the tolerance for impurity gases (e.g., CO) other than the above is large, gases containing a large amount of impurity gases, such as adsorption off-gas containing non-adsorbed gas components in the adsorption step of a PSA facility, can also be supplied to the gas utilization facility and utilized.

[0054] Here, the term "non-adsorbed gas component" refers to a gas component that is not simply adsorbed to the adsorbent in the adsorption step, and does not refer to a gas component that is not adsorbed to the adsorbent. For example, when the raw gas is CO ２ , CO and H ２ When the adsorbent is a zeolite, the adsorption strength to the adsorbent is ２ , CO and H ２ Therefore, the adsorption off-gas at the beginning of the adsorption process is ２ However, if the adsorption process is continued, breakthrough occurs and CO ２ The CO that was not adsorbed by the adsorbent due to breakthrough will also no longer be adsorbed by the adsorbent. ２are also included in the above "non-adsorbed gas components."

[0055] When the adsorption off-gas is supplied to a gas utilization facility as described above, it is preferable to switch the supply destination of the adsorption off-gas to the gas utilization facility based on the concentration of the target gas component in the adsorption off-gas (adsorption off-gas utilization facility switching step).

[0056] That is, the composition (concentration of the target gas component) of the adsorption off-gas containing the non-adsorbed gas component that was not adsorbed by the adsorbent in the target gas component adsorption step also varies over time, similar to the desorbed gas. ２ , CO and H ２ When the adsorbent is a zeolite, the adsorption off-gas at the beginning of the adsorption process contains H ２ The off-gas in the early stage of the adsorption process is mostly composed of H and the concentration of CO increases as the adsorption process continues. ２ During the middle stage of the adsorption process, ２ Therefore, it is possible to supply an appropriate gas to the gas-using equipment depending on the composition of the adsorption off-gas.

[0057] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0058] According to the flow diagram of the gas separation process shown in Figure 2, blast furnace gas was introduced into a gas separation facility, and the desorbed gas was supplied to a gas utilization facility. Specifically, first, the blast furnace gas discharged from a blast furnace, which is a reduction furnace, was reformed and purified by a pretreatment facility. Next, the reformed and purified gas was used as a raw material gas and introduced into one of two adsorption towers constituting the gas separation facility (PSA facility), in which the valve V1 on the exhaust line was open and the valve V2 was closed (the other adsorption tower had the valve V1 closed and the valve V2 open). CO contained in the blast furnace gas was then desorbed. ２ The target gas component was adsorbed onto an adsorbent (13X zeolite) packed in an adsorption tower (target gas component adsorption step). The adsorption off-gas that was not adsorbed onto the adsorbent in this target gas component adsorption step was introduced into a gas tank 1 provided upstream of a methanol synthesis reactor using a Cu—Zn catalyst.

[0059] Next, the CO adsorbed on the adsorbent is removed by the vacuum pump VP. ２ Desorb CO ２ The desorption gas containing CO was discharged from the adsorption tower (target gas component desorption step). This target gas component desorption step was divided into two time periods according to the change in the composition of the desorbed gas over time. In the early desorption step, valve V1 of the adsorption tower was closed, valve V2 was opened, valve V3 was opened, and valve V4 was closed. ２ The desorbed gas with a low concentration was introduced into the gas tank 1 provided in the upstream of the methanol synthesis reactor and mixed with the adsorption off-gas (mixing step). Then, in the later period of the desorption step, the valve V3 was closed and the valve V4 was opened to switch the supply destination of the desorbed gas to the methane synthesis reactor, and a relatively low CO ２ The desorbed gas with a high concentration was introduced into the gas tank 2, which was installed in the upstream of the methane synthesis reactor using a Ni catalyst. Then, at the stage where the gases introduced into the gas tank 1 and the gas tank 2 were sufficiently mixed, the gas in the gas tank 1 was mixed with H ２ The gas in the gas tank 2 was supplied to the methanol synthesis reactor together with the H ２ The methane was then fed to a methane synthesis reactor along with the gas to synthesize methane, which was then fed to a blast furnace as a reducing agent to reduce the oxides contained in the iron ore.

[0060] The pressure swing adsorption method is useful in the steel industry because it can separate suitable gases from a raw gas and supply them to multiple gas utilization facilities.

Claims

1. A gas separation method for adsorbing and separating a target gas component from a raw material gas containing two or more gas components by pressure swing adsorption, comprising: a target gas component adsorption step of introducing the raw material gas into an adsorption tower filled with an adsorbent and causing the target gas component to be adsorbed by the adsorbent; a target gas component desorption step of desorbing the target gas component adsorbed by the adsorbent in the target gas component adsorption step and discharging a desorbed gas containing the target gas component from the adsorption tower; and a desorbed gas supply step of supplying the desorbed gas discharged from the adsorption tower in the target gas component desorption step to two or more different gas utilization facilities, wherein the target gas component desorption step includes a desorbed gas utilization facility switching step of switching the supply destination of the desorbed gas to the gas utilization facility in the desorbed gas supply step.

2. The gas separation method according to claim 1, wherein the raw gas contains at least carbon dioxide and carbon monoxide.

3. A gas separation method according to claim 1 or 2, characterized in that the raw material gas is an exhaust gas discharged from a reduction furnace.

4. A gas separation method described in any one of claims 1 to 3, characterized in that the switching of the supply destination to the gas utilization equipment in the desorption gas utilization equipment switching process is carried out at the boundaries of the multiple divided time periods by dividing the desorption process into multiple time periods.

5. A gas separation method according to any one of claims 1 to 4, further comprising, prior to the desorption gas supply step, either or both of a desulfurization step for removing sulfur from the raw material gas or the desorption gas, and a water-gas shift reaction step for producing carbon dioxide from carbon monoxide and water contained in the raw material gas or the desorption gas.

6. A gas separation method according to any one of claims 1 to 5, wherein the target gas component adsorption process further comprises an adsorption off-gas supply process for supplying an adsorption off-gas containing non-adsorbed gas components that were not adsorbed by the adsorbent in the target gas component adsorption process to one of the two or more different gas utilization facilities.

7. The gas separation method described in claim 6, wherein the target gas component adsorption process includes an adsorption off-gas utilization equipment switching process for switching the supply destination of the adsorption off-gas to the gas utilization equipment based on the concentration of the target gas component in the adsorption off-gas.

8. A gas separation method described in any one of claims 1 to 7, characterized in that it further comprises a gas mixing process, after the target gas component desorption process and before the desorption gas supply process, for mixing the desorption gases discharged from the adsorption tower having different concentrations of the target gas component.

9. The gas separation method according to any one of claims 1 to 8, wherein one of the two or more gas utilization facilities is a methanol synthesis reactor.

10. A gas separation method according to any one of claims 1 to 9, wherein one of the two or more gas utilization facilities is a methane synthesis reactor.

11. One of the two or more gas utilization facilities is CO ２ The gas separation method according to any one of claims 1 to 8, characterized in that it is a liquefaction facility.

12. A gas separation method according to claim 10, which relies on claim 2 or 3, or claim 11, which relies on claim 2 or 3, characterized in that the product of the gas utilization facility is supplied as a reducing agent to the reduction furnace.

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