Gas purification method and gas purification device

Abstract

The invention provides a gas purification method and a gas purification device, which can efficiently utilize regeneration gas without a compressor and the like, can reduce the discharge gas amount of the regeneration gas, and can improve the recovery rate of product gas. Provided is a gas purification method in which an adsorption process for adsorbing and removing impurities in a raw material gas (G1) and a regeneration process for separating the impurities from the adsorption towers (2A, 2B, 2C) by heating the adsorption towers (2A, 2B, 2C) are repeatedly performed using three adsorption towers (2A, 2B, 2C), and the adsorption process is performed by at least one of the adsorption towers (2A, 2B, 2C). And a part of a purified gas (G2) obtained by removing impurities from the raw material gas (G1), which is discharged from the adsorption towers in the adsorption process, is used as a regeneration gas (G3) for purging the adsorption towers (2A, 2B, 2C) in the regeneration process, in which when at least two of the three adsorption towers (2A, 2B, 2C) perform the regeneration process, a part of the purified gas (G2) is discharged from the adsorption towers (2A, 2B, 2C) is used as the regeneration gas (G3) for purging the adsorption towers (2A, 2B, 2C). A regeneration gas (G3) sequentially flows through each adsorption tower (2B, 2C) for performing a regeneration process.

Description

Technical Field

[0001] The present invention relates to a gas refining method and a gas refining device. Background Art

[0002] Conventionally, in industrial gas production processes, gas purification systems (TSA systems) employing thermal swing adsorption (TSA) are known as a method for purifying gases containing impurities to produce product gases (purified gases). Generally, TSA systems employ a dual-tower switching structure to continuously supply product gases. These systems utilize two adsorption towers for adsorbing impurities, alternating between a purification process (adsorbing impurities) and a regeneration process (desorbing impurities).

[0003] In a typical gas purification system with a dual-tower switching structure and utilizing the TSA method, when regenerating the adsorbent in the adsorption tower after gas purification, a portion of the product gas or a gas that is not adsorbable to the adsorbent is supplied to the adsorption tower as regeneration gas, heating the adsorbent in the adsorption tower while simultaneously desorbing the target to be removed. The adsorbent is heated, for example, by regeneration gas heated by a gas heater and heat input from a jacketed heater installed in the adsorption tower. Activated carbon and zeolite, commonly used as adsorbents, have low thermal conductivity, making uniform heating difficult through external heating such as jacketed heaters. Therefore, heat transfer using the regeneration gas as a medium is crucial, and this trend becomes more pronounced with larger adsorption towers. Furthermore, the flow rate of regeneration gas required for adsorbent regeneration—that is, the amount of heat required to be transferred per unit time—depends not only on the specific heat and temperature of the regeneration gas during the regeneration process, but also on the regeneration time, the amount of adsorbed target to be removed, the amount of heat required for desorption, and the heat capacity of the adsorption tower and adsorbent.

[0004] As mentioned above, using a portion of the product gas as regeneration gas directly contributes to product gas loss. Furthermore, preparing a separate gas that is not adsorbable to the adsorbent and using it as regeneration gas not only increases utility costs but also causes the non-adsorbable gas to remain in the adsorption tower, becoming an impurity in the product gas, thereby reducing the purity of the product gas. Therefore, improving product gas recovery by reducing exhaust gas from the regeneration gas and efficiently heating and cooling the adsorbent are important factors in improving the economic efficiency of gas purification equipment using the TSA method.

[0005] On the other hand, in the case of a dual-tower switching gas purification system (TSA system) as described above, the time available for the regeneration process depends on the amount of adsorbent filled in the adsorption tower, that is, the adsorption process time. Therefore, for example, if the regeneration gas flow rate is reduced, not only does the amount of heat that can be transferred per unit time by the regeneration gas decrease, but the amount of heat that can be removed per unit time during cooling also decreases. Even if the regeneration gas temperature is increased during regeneration, the amount of heat to be removed during cooling increases, potentially leading to insufficient cooling of the adsorbent. Therefore, in a dual-tower switching gas purification system (TSA system), improving the recovery rate by reducing the regeneration gas flow rate has limitations.

[0006] Here, as a method for improving the recovery rate of product gas in a gas purification device, for example, a technique described in Patent Document 1 is known.

[0007] The regenerative desulfurization system described in Patent Document 1 consists of two regenerative gas purification units (hereinafter referred to as Unit A and Unit B for ease of explanation) connected in series. The exhaust gas from the regeneration gas passed through the regeneration-side adsorption tower of Unit A is then passed as regeneration gas to the regeneration-side adsorption tower of Unit B. The technology described in Patent Document 1 reduces the amount of regeneration gas used in the entire system.

[0008] As another method for improving the recovery rate of product gas in a gas purification device, for example, the technology described in Patent Document 2 is known.

[0009] According to the helium purification apparatus described in Patent Document 2, the exhaust gas of the regeneration gas is joined to the raw gas line and recycled as the raw gas, thereby improving the recovery rate of the product gas by reusing the exhaust gas of the regeneration gas.

[0010] Patent Document 1: Japanese Patent No. 5074116

[0011] Patent Document 2: Japanese Patent No. 4058278

[0012] However, the technology described in Patent Document 1 cannot reduce the amount of exhaust gas of the regeneration gas in the unit cell (eg, unit cell A or unit cell B) to improve the recovery rate of the product gas.

[0013] Furthermore, the technology described in Patent Document 2 requires equipment such as a compressor to increase the pressure of the exhaust gas to a pressure higher than the pressure of the raw gas in order to reuse the exhaust gas from the regeneration gas. This increases the cost of the equipment and may limit the applicable processes. Summary of the Invention

[0014] The present invention is proposed in view of the above problems, and its purpose is to provide a gas purification method and a gas purification device, which can efficiently utilize the regeneration gas without the need for a compressor, etc., and can reduce the amount of exhaust gas of the regeneration gas to improve the recovery rate of the product gas.

[0015] To address the above-mentioned issues, the inventors conducted extensive research. As a result, they discovered that by utilizing a TSA apparatus with a multi-tower switchable structure comprising three or more adsorption towers and providing a pipeline connecting the towers, regeneration gas could be efficiently utilized without the need for a compressor, etc. Specifically, they discovered that the amount of regeneration gas discharged could be reduced and the recovery rate of product gas could be improved by employing the following method, thereby completing the present invention. This method involves sequentially circulating regeneration gas to the adsorption towers performing the regeneration process when at least two of the three adsorption towers are undergoing the regeneration process.

[0016] That is, the present invention has the following aspects.

[0017] [1] A gas purification method, characterized in that at least three adsorption towers filled with an adsorbent for adsorbing impurities in a raw gas are used, and an adsorption process and a regeneration process are repeatedly performed by a thermal swing adsorption (TSA) method, wherein the adsorption process adsorbs and removes the impurities in the raw gas in the adsorption tower, and the regeneration process heats the adsorption tower to remove the impurities adsorbed in the adsorption tower from the adsorption tower, and in the gas purification method, the adsorption process is performed in at least one of the three adsorption towers, and a portion of the purified gas discharged from the adsorption tower and obtained by removing the impurities from the raw gas in the adsorption process is used as a regeneration gas for purging the adsorption tower in the regeneration process, and gas purification is performed while the regeneration process is performed on at least two of the three adsorption towers. The regeneration gas is sequentially circulated to each of the adsorption towers performing the regeneration process.

[0018] [2] The gas purification method according to the above-mentioned [1] is characterized in that the regeneration process includes at least a heating process for heating the adsorption tower and a cooling process for cooling the adsorption tower after the heating process to a temperature at which the adsorption process can be implemented. When at least one of the three adsorption towers implements the heating process and at least one of the adsorption towers implements the cooling process, the regeneration gas is introduced into the adsorption tower that is implementing the cooling process, and at the same time, the regeneration gas discharged from the adsorption tower that is implementing the cooling process is introduced into the adsorption tower that is implementing the heating process.

[0019] [3] The gas purification method according to [1] or [2] above is characterized in that the temperature of the regeneration gas is cooled to below 150°C before the regeneration gas discharged from the adsorption tower undergoing the cooling process is introduced into the adsorption tower undergoing the heating process.

[0020] [4] The gas purification method according to [1] or [2] above is characterized in that the component contained in the impurities adsorbed and removed by the adsorbent is at least any one of H2O, CO2, O2, CO and hydrocarbons.

[0021] [5] A gas purification device for adsorbing and removing impurities from a raw gas to generate a purified gas, characterized in that it comprises: at least three adsorption towers filled with an adsorbent for adsorbing and removing the impurities from the raw gas; a raw gas inlet pipe and a regeneration gas outlet pipe respectively connected to one end of the adsorption tower, the raw gas inlet pipe being used to introduce the raw gas into the adsorption tower, and the regeneration gas outlet pipe being used to discharge the regeneration gas introduced into the adsorption tower from the adsorption tower; a product gas outlet pipe and a regeneration gas inlet pipe respectively connected to the other end of the adsorption tower, the product gas outlet pipe being used to discharge the purified gas from the adsorption tower, The regeneration gas inlet pipe is used to introduce the regeneration gas into the adsorption tower; the opening and closing valves are respectively arranged on one end side or the other end side of the adsorption tower on the raw gas inlet pipe, the regeneration gas exhaust pipe, the product gas outlet pipe and the regeneration gas inlet pipe; and a heating part is arranged on the adsorption tower and used to heat the adsorbent or the regeneration gas, and an adsorption tower connecting pipe is arranged between the three adsorption towers. The adsorption tower connecting pipe connects the one end of the adsorption tower connected to the regeneration gas exhaust pipe and the other end connected to the regeneration gas inlet pipe, and a switching valve is provided on the adsorption tower connecting pipe.

[0022] [6] The gas purification device according to the above [5] is characterized in that the adsorption tower connecting pipe is configured to connect all three adsorption towers in a ring shape.

[0023] [7] The gas purification device according to [5] or [6] above is characterized in that the heat-resistant temperature of the switching valve provided on the adsorption tower connecting pipe is at least higher than the heating temperature of the adsorption tower.

[0024] [8] The gas purification device according to [5] or [6] above is characterized in that a heat exchanger for cooling the regeneration gas flowing in the adsorption tower connecting pipe is provided on the primary side of the switching valve provided on the adsorption tower connecting pipe.

[0025] [9] The gas purification device according to [5] or [6] above is characterized in that a heat exchanger for cooling the gas flowing in the regeneration gas exhaust pipe is provided between the adsorption tower and the on-off valve provided on the regeneration gas exhaust pipe.

[0026]

[10] The gas purification device according to the above [9] is characterized in that a drain trap is provided inside the heat exchanger provided on the regeneration gas exhaust pipe or on the regeneration gas exhaust pipe on the outlet side of the heat exchanger.

[0027]

[11] The gas purification device according to [5] or [6] above is characterized in that the component contained in the impurities adsorbed and removed by the adsorbent is at least any one of H2O, CO2, O2, CO and hydrocarbons.

[0028] As described above, the gas purification method of the present invention adopts a method in which, when at least two of the three adsorption towers are undergoing the regeneration process, the regeneration gas is sequentially passed through the adsorption towers undergoing the regeneration process.

[0029] According to the present invention, by employing the above-described method, the flow rate of the regeneration gas required for heating and cooling the adsorption tower can be reduced, and the flow rate of the exhaust gas discharged from the adsorption tower during the regeneration process can also be reduced. This reduces the amount of exhaust gas contained in the purified gas and improves the recovery rate of the product gas.

[0030] In addition, the gas purification device of the present invention adopts the following structure: that is, an adsorption tower connecting pipe is arranged between the three adsorption towers, and the adsorption tower connecting pipe connects one end of the adsorption tower connected to the regeneration gas exhaust pipe and the other end connected to the regeneration gas inlet pipe, and a switching valve is arranged on the adsorption tower connecting pipe.

[0031] According to the present invention, by adopting the above-described structure, the flow rate of the regeneration gas required for heating and cooling the adsorption tower can be reduced, as described above, and the flow rate of the exhaust gas of the regeneration gas discharged from the adsorption tower can also be reduced. Furthermore, the regeneration gas can be efficiently utilized without requiring a compressor or the like. This provides a gas purification system that can reduce the amount of exhaust gas of the regeneration gas contained in the purified gas and improve the recovery rate of the product gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A diagram schematically illustrating a gas purification method and a gas purification device according to a first embodiment of the present invention is a system diagram showing the overall configuration of the gas purification device.

[0033] Figure 2The figure is a diagram schematically illustrating a gas purification method and a gas purification device according to a first embodiment of the present invention. Figure 1 A system diagram showing an example of the flow of raw gas, purified gas, and regeneration gas in a gas purification device based on a valve timing diagram is shown.

[0034] Figure 3 The figure is a diagram schematically illustrating a gas purification method and a gas purification device according to a first embodiment of the present invention. Figure 1 A system diagram showing another example of the flow of raw gas, purified gas, and regeneration gas in the gas purification device shown.

[0035] Figure 4 This figure schematically illustrates a gas purification method and a gas purification device according to a first embodiment of the present invention. Figure 2 and Figure 3 The valve timing diagram shows the opening and closing operations of the valves for controlling the flow of raw gas, purified gas and regeneration gas.

[0036] Figure 5 A diagram schematically illustrating a gas purification method and a gas purification device according to a second embodiment of the present invention is a system diagram showing the overall configuration of the gas purification device.

[0037] Figure 6 A diagram schematically illustrating a gas purification method and a gas purification device according to a third embodiment of the present invention is a system diagram showing the overall configuration of the gas purification device.

[0038] Figure 7 The diagram schematically illustrates a gas purification method and a gas purification device according to the second to fourth embodiments of the present invention. Figure 5 and Figure 6 The valve timing diagram shows the opening and closing operations of the valves that control the flow of raw gas, purified gas, and regeneration gas.

[0039] Figure 8 A diagram schematically illustrating a gas purification method and a gas purification device according to a fourth embodiment of the present invention is a system diagram showing the overall configuration of the gas purification device. DETAILED DESCRIPTION

[0040] Hereinafter, the gas purification method and gas purification apparatus according to the first to fourth embodiments of the present invention will be described with reference to the following. Figures 1 to 8 To explain.

[0041] In addition, for the drawings used in the following description, in order to facilitate understanding of the features, the features may be enlarged or simplified for convenience. In addition, the materials and the like illustrated in the following description are examples, and the present invention is not limited to those materials and the like, and can be appropriately modified within the scope of not changing the gist of the present invention.

[0042] <First embodiment>

[0043] Next, a gas purification method and a gas purification device according to a first embodiment of the present invention will be described.

[0044] [Gas purification device]

[0045] First, a gas purification device that can be used in an operation using the gas purification method of this embodiment will be described in detail below.

[0046] Figure 1 It is a system diagram showing the general structure of the gas purification device 1 according to the first embodiment.

[0047] Figure 2 and Figure 3 To express in Figure 1 The system diagram of the flow of raw gas, purified gas, and regeneration gas in the gas purification device 1 shown is based on the valve timing diagram.

[0048] Figure 4 For Figure 1 In the operation of the gas purification device 1 shown, Figure 2 and Figure 3 The valve timing diagram shown is used to control the opening and closing of each valve for controlling the flow of raw gas, purified gas and regeneration gas. Figure 4 In the figure, the time period marked with slashes indicates that the valve is in the open state, and the time period marked with dots in the heating section row indicates that the heating section is operating and heating the adsorption tower.

[0049] The gas purification device 1 of this embodiment is a so-called TSA device that removes impurities in the raw gas G1 by the TSA method to obtain the purified gas G2. Figure 1 As shown, the gas refining device 1 of this embodiment is roughly constructed to have adsorption towers 2A, 2B, 2C, a raw gas inlet path (raw gas inlet pipe) L1, a product gas outlet path (product gas outlet pipe) L2, a regeneration gas inlet path (regeneration gas inlet pipe) L3 and a regeneration gas outlet path (regeneration gas exhaust pipe) L4.

[0050] More specifically, the gas purification device 1 includes three adsorption towers 2A, 2B, and 2C, each filled with an adsorbent 6 for removing impurities from the raw gas G1 by adsorption. Each of the adsorption towers 2A, 2B, and 2C is provided with a heating unit 9 for heating the adsorbent 6 or the regeneration gas G3.

[0051] In addition, the gas purification device 1 has a raw gas inlet path L1 and a regeneration gas outlet path L4 respectively connected to one end 2a of the adsorption towers 2A, 2B, and 2C. The raw gas inlet path L1 is used to introduce the raw gas G1 into the adsorption towers 2A, 2B, and 2C, and the regeneration gas outlet path L4 is used to discharge the regeneration gas G3 from the adsorption towers 2A, 2B, and 2C.

[0052] In addition, the gas purification device 1 has a product gas outlet path L2 and a regeneration gas inlet path L3 respectively connected to the other end 2b of the adsorption towers 2A, 2B, and 2C. The product gas outlet path L2 is used to discharge the purified gas G2 from the adsorption towers 2A, 2B, and 2C, and the regeneration gas inlet path L3 is used to introduce the regeneration gas into the adsorption towers 2A, 2B, and 2C.

[0053] In addition, the gas refining device 1 has opening and closing valves V1a, V1b, V1c, V2a, V2b, V2c, V3a, V3b, V3c, V4a, V4b, V4c, which are respectively arranged on one end 2a side or the other end 2b side of the adsorption towers 2A, 2B, and 2C on the raw gas inlet path L1, the product gas outlet path L2, the regeneration gas inlet path L3, and the regeneration gas outlet path L4.

[0054] Furthermore, the gas purification apparatus 1 of this embodiment has an adsorption tower connecting path (adsorption tower connecting pipe) L5 ​​disposed between the three adsorption towers 2A, 2B, and 2C. This path connects one end 2a of each of the adsorption towers 2A, 2B, and 2C, which is connected to the regeneration gas outlet path L4, with the other end 2b connected to the regeneration gas inlet path L3. Furthermore, switching valves V5a, V5b, V5c, V5d, V5e, and V5f are disposed on the adsorption tower connecting path L5 near the adsorption towers 2A, 2B, and 2C, respectively.

[0055] In addition, the gas refining device 1 shown in the figure is provided with connecting pipes L6a, L6b, L6c connecting the confluence of the raw gas inlet path L1 and the regeneration gas outlet path L4 to one end 2a of each of the three adsorption towers 2A, 2B, 2C, and connecting pipes L7a, L7b, L7c connecting the confluence of the product gas outlet path L2 and the regeneration gas inlet path L3 to the other end 2b of each of the three adsorption towers 2A, 2B, 2C.

[0056] Furthermore, the gas purification device 1 of the illustrated example includes a regeneration gas flow rate regulating valve NV1 provided in the vicinity of a point where the regeneration gas introduction path L3 branches off from the product gas outlet path L2 .

[0057] The gas purification device 1 of the present embodiment has the above-described adsorption tower connecting path L5 , and is configured such that the three adsorption towers 2A, 2B, and 2C are connected to form a ring-shaped path.

[0058] The raw gas inlet path L1 is used to introduce the raw gas G1 to be purified into the adsorption towers 2A, 2B, and 2C of the gas purification device 1. One end of the illustrated raw gas inlet path L1 is connected to a raw gas storage device (not shown). The other end of the raw gas inlet path L1 branches into three connecting pipes L6a, L6b, and L6c, which are connected to one end 2a of each of the three adsorption towers 2A, 2B, and 2C. The connection point between the raw gas inlet path L1 and the connecting pipes L6a, L6b, and L6c is the confluence of the raw gas inlet path L1, the regeneration gas outlet path L4, and the adsorption tower connection path L5.

[0059] On the branch path on the other end side of the raw gas introduction path L1, opening and closing valves V1a, V1b, and V1c are provided, respectively, so as to be able to start and stop the flow of the raw gas G1.

[0060] The product gas extraction path L2 is used to extract the purified gas G2 purified in the adsorption towers 2A, 2B, and 2C as product gas (purified gas G2). The illustrated product gas extraction path L2 branches into three paths at one end, connecting to connecting pipes L7a, L7b, and L7c (not shown) connected to the other ends 2b of the three adsorption towers 2A, 2B, and 2C, respectively. The other end of the path is connected to product gas storage equipment (not shown). A branch point into the regeneration gas introduction path L3 is located near the other end of the product gas extraction path L2.

[0061] On one end of the product gas outlet path L2, on the path before branching into three connecting pipes L7a, L7b, and L7c, opening and closing valves V2a, V2b, and V2c are respectively provided, thereby being constructed to be able to start and stop the flow of the purified gas G2 as the product gas.

[0062] The regeneration gas introduction path L3 is used to extract a portion of the purified gas G2 from the product gas outlet path L2 as regeneration gas G3. One end of the regeneration gas introduction path L3 is connected to the product gas outlet path L2, and the regeneration gas introduction path L3 branches off at a point closer to the other end than the point on the product gas outlet path L2 where it branches off to the connecting pipes L7a, L7b, and L7c.

[0063] The other end side of the regeneration gas introduction path L3 shown in the figure branches into three, which are respectively connected to the connection pipes L7a, L7b, and L7c connected to the other ends 2b of the three adsorption towers 2A, 2B, and 2C.

[0064] In addition, on the other end side of the regeneration gas introduction path L3, on-off valves V3a, V3b, and V3c are respectively provided on the path before it branches into three connecting pipes L7a, L7b, and L7c, thereby being constructed to be able to start and stop the flow of the regeneration gas G3.

[0065] As described above, a regeneration gas flow control valve NV1 is provided on the regeneration gas inlet path L3 near the point where it branches off from the product gas outlet path L2. This regeneration gas flow control valve NV1 controls the flow rate of the regeneration gas G3 during the regeneration process for regenerating the adsorbent 6 filled in the adsorption towers 2A, 2B, and 2C, supplying a predetermined flow rate of the regeneration gas G3 to the adsorption towers 2A, 2B, and 2C.

[0066] The regeneration gas flow rate adjustment valve NV1 is not particularly limited, and for example, a flow rate control device such as a conventional flow meter or MFC (Mass Flow Controller) can be used.

[0067] The regeneration gas outlet path L4 is a path for discharging the regeneration gas G3 used in the regeneration process from the adsorption towers 2A, 2B, and 2C as exhaust gas. One end of the regeneration gas outlet path L4 branches into three connecting pipes L6a, L6b, and L6c, which are connected to the one ends 2a of the three adsorption towers 2A, 2B, and 2C, respectively. The other end of the regeneration gas outlet path L4 is connected to exhaust gas treatment equipment (not shown).

[0068] In addition, on one end side of the regeneration gas derivation path L4, on the path before it branches into three and becomes connecting pipes L6a, L6b, and L6c, opening and closing valves V4a, V4b, and V4c are respectively provided, thereby being constructed to be able to start and stop the flow of the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C as exhaust gas.

[0069] An adsorption tower connecting path L5 is provided between the three adsorption towers 2A, 2B, and 2C. This adsorption tower connecting path L5 connects one end 2a connected to the regeneration gas outlet path L4 with the other end 2b connected to the regeneration gas inlet path L3. Switching valves V5a, V5b, V5c, V5d, V5e, and V5f are provided on the adsorption tower connecting path L5 near the adsorption towers 2A, 2B, and 2C, respectively.

[0070] In the illustrated example, one end side of the adsorption tower connection path L5 branches into three branches, which are respectively connected to the connection pipes L6a, L6b, and L6c connected to the one ends 2a of the three adsorption towers 2A, 2B, and 2C.

[0071] In addition, similar to the one end side of the adsorption tower connecting path L5, the other end side of the adsorption tower connecting path L5 is also branched into three, and respectively connected to the connecting pipes L7a, L7b, and L7c connected to the other ends 2b of the three adsorption towers 2A, 2B, and 2C.

[0072] One of the switching valves V5a, V5b, and V5c is disposed on one end of the adsorption tower connecting path L5, near the connection with the connecting pipes L6a, L6b, and L6c. Furthermore, one of the switching valves V5d, V5e, and V5f is disposed on the other end of the adsorption tower connecting path L5, near the connection with the connecting pipes L7a, L7b, and L7c.

[0073] Adsorption towers 2A, 2B, and 2C are separation devices for removing impurities contained in raw gas G1 by adsorption using adsorbent 6 to obtain purified gas G2. Specifically, adsorption towers 2A, 2B, and 2C include adsorbent 6 disposed within a cylindrical housing 5 and a heating unit 9 disposed so as to cover the outer peripheral surface of the housing 5.

[0074] The housing 5 is preferably made of a material that is heat-resistant, pressure-resistant, and corrosion-resistant. The material of the housing 5 can be appropriately selected based on, for example, the internal temperature and pressure conditions, the adsorbent, the raw gas G1 used, and the impurities contained in the raw gas G1. However, a material that allows repeated gas purification under these conditions is preferred. For example, as described in detail below, when the heating process included in the regeneration process is performed at a temperature of 300°C or higher, synthetic zeolite is used as the adsorbent 6, hydrogen is used as the raw gas G1, and the impurity in the raw gas G1 is carbon monoxide, the housing 5 is preferably made of a metal such as stainless steel.

[0075] The housing 5 may be any container capable of introducing the raw gas G1 and the regeneration gas G3, discharging the purified gas G2 and the regeneration gas G3 used for regeneration, and being filled with the adsorbent 6. Examples of the housing 5 include a cylindrical housing with openings at one end 2a and the other end 2b.

[0076] The adsorbent 6 is used to remove impurities from the raw gas G1. The adsorbent 6 is filled in the inner space of the housing 5. As the adsorbent 6, one or more adsorbents capable of selectively adsorbing impurities in the raw gas G1 can be used.

[0077] Adsorbent 6 may be, for example, silica gel, zeolite, activated alumina, activated carbon, or the like, but is not limited thereto. The adsorbent 6 may be appropriately selected based on the raw gas G1 to be purified and the gas components containing impurities. Furthermore, the shape and size of adsorbent 6 within housing 5 may be appropriately determined.

[0078] Furthermore, in addition to the adsorbent 6, a catalyst (not shown) for promoting the adsorption process and the regeneration process may be arranged inside the housing 5. Examples of such a catalyst include palladium, copper, and ruthenium.

[0079] When regenerating the adsorbent 6 , the heating unit 9 heats the housing 5 from the outside, thereby heating the adsorbent 6 and the regeneration gas G3 .

[0080] The heating portion 9 may be arranged so as to cover the outer peripheral surface of the housing 5 , and preferably, a heating portion wound helically with respect to the axial direction of the housing 5 is used as in the example shown in the figure.

[0081] The heating unit 9 may be provided in a state of contact with the outer peripheral surface of the housing 5. In this way, the heat generated by the heating unit 9 can be efficiently transferred to the housing 5. On the other hand, the heating unit 9 is not limited to a structure provided in a state of contact with the housing 5, and may also be a structure provided in a state of non-contact with the housing 5.

[0082] In addition, for Figure 1 As in the example shown in FIG, the heating portions 9 spirally arranged around the housing 5 are spaced apart so that the heating portions 9 adjacent to each other in the axial direction of the housing 5 do not contact each other. However, for example, the heating portions 9 may contact each other.

[0083] While not particularly limited, examples of the heating unit 9 include a sheath heater, a heating tube through which a hot fluid flows, and an insulated nickel heating wire. Furthermore, the number of heating units 9 may be one or more. Furthermore, the heating temperature of the heating unit 9 is not particularly limited; it only needs to be a temperature that can heat the adsorbent 6 or the regeneration gas G3 to any desired temperature.

[0084] Although Figure 1 Although not shown in the figure, the adsorption towers 2A, 2B, and 2C may be provided with cooling means for cooling the adsorbent 6 disposed inside the housing 5. Examples of such cooling means include cooling pipes having a structure in which a condensing agent flows.

[0085] In this embodiment, a heat transfer material (not shown) may be disposed to assist in the transfer of cooling energy generated by the cooling pipe and heat energy generated by the heating unit 9 to the housing 5. For example, this heat transfer material may be arranged to cover the entire housing 5 and heating unit 9, as well as a portion of the outer circumference of the cooling pipe (not shown), with a uniform thickness around the circumference of the housing 5. This heat transfer material can expand the heat transfer area between the cooling pipe and heating unit 9 and the housing 5, thereby improving the heat transfer efficiency between the cooling pipe and heating unit 9 and the housing 5.

[0086] The material of the heat transfer material may be any material having a thermal conductivity of 1 or higher, and examples thereof include "Thermal Conductive Cement HTC (registered trademark)" from Nippon Heater Co., Ltd. and "Thermon T-99 (registered trademark)" from Sakaguchi Electric Heat Co., Ltd.

[0087] The heat insulating material (not shown) is used to prevent heat exchange with the outside of the adsorption towers 2A, 2B, and 2C. The provision of the heat insulating material (not shown) prevents heat from flowing out of the adsorption towers 2A, 2B, and 2C during the heating process (regeneration process) for regenerating the adsorbent 6 disposed in the adsorption towers 2A, 2B, and 2C, and prevents heat from flowing into the adsorption towers 2A, 2B, and 2C from the outside during the cooling process (regeneration process). This improves heat transfer efficiency during the regeneration process for regenerating the adsorbent 6 in the adsorption towers 2A, 2B, and 2C.

[0088] The heat insulating material described above can be provided, for example, to cover the outer peripheral surface of the shell 5. Furthermore, a space for installing a cooling pipe and a heating unit 9 (not shown) can be provided between the outer peripheral surface of the shell 5 and the heat insulating material. Thus, the heat insulating material is arranged to cover the shell 5, the cooling pipe, and the heating unit 9, thereby preventing heat from flowing out of the adsorption towers 2A, 2B, and 2C to the outside during the heating process (regeneration process) for regenerating the adsorbent 6 in the adsorption towers 2A, 2B, and 2C, and preventing heat from flowing into the adsorption towers 2A, 2B, and 2C from the outside during the cooling process (regeneration process).

[0089] As the heat insulating material described above, any material having a thermal conductivity lower than 1 is sufficient, and a material having a lower thermal conductivity is preferred. Examples of the heat insulating material include glass wool and rock wool, but are not particularly limited.

[0090] In the adsorption towers 2A, 2B, and 2C included in the gas purification device 1 of the present embodiment, components contained in the impurities adsorbed and removed by the adsorbent 6 include, for example, at least one of H 2 O, CO 2 , O 2 , CO, and hydrocarbons.

[0091] According to the gas purification apparatus 1 of this embodiment, since it includes the adsorption tower connecting path L5 having the above-described structure, when, for example, a regeneration process of the adsorbent 6 is being performed in at least two of the three adsorption towers 2A, 2B, and 2C, the regeneration gas G3 can be sequentially circulated to each adsorption tower undergoing the regeneration process. This allows efficient utilization of the regeneration gas G3 in the regeneration process without requiring a compressor or the like. Furthermore, the flow rate of the regeneration gas G3 required for heating and cooling the adsorption towers 2A, 2B, and 2C can be reduced, thereby also reducing the flow rate of the exhaust gas of the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C. Consequently, the amount of exhaust gas of the regeneration gas G3 contained in the purified gas G2, which is the product gas, can be reduced, thereby improving the recovery rate of the product gas.

[0092] The gas type, flow rate, pressure, and temperature of the raw gas G1 to be purified by the gas purification apparatus 1 of this embodiment are not particularly limited; examples thereof include air, noble gases (e.g., He, Ar, Xe, Kr, Ne), hydrogen, methane, and hydrocarbons. The gas purification apparatus 1 of this embodiment is particularly suitable for use in gas generation systems such as hydrogen generation systems where the gas production volume (raw gas volume) is limited and an increase in the product gas volume (usable gas volume) is desired.

[0093] Furthermore, in the gas purification apparatus 1 of this embodiment, the switching valves V5a, V5b, V5c, V5d, V5e, and V5f provided on the adsorption tower connecting path L5 preferably have a heat-resistant temperature that is at least equal to or higher than the heating temperature of the adsorption towers 2A, 2B, and 2C. This prevents damage to the switching valves due to high temperatures during the heating process (regeneration process) for regenerating the adsorbent 6 in the adsorption towers 2A, 2B, and 2C.

[0094] Furthermore, in this embodiment, if a gas heating heater is used as a heating unit, the number of required heating units can be reduced by installing the heating unit in the adsorption tower connecting path L5 connected to the adsorption towers 2A, 2B, and 2C. When a heating unit is installed in the adsorption tower connecting path L5, the switching valves V5d, V5e, and V5f connected to the other end 2b of the adsorption towers 2A, 2B, and 2C must be heat-resistant valves capable of operating at the heating temperature of the heating unit. Furthermore, even if a heating unit is not installed in the adsorption tower connecting path L5, since the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C is high temperature, as described above, the switching valves V5a, V5b, and V5c and the on-off valves V4a, V4b, and V4c through which the high-temperature regeneration gas G3 flows must also be heat-resistant valves capable of operating at the heating temperature of the adsorption towers 2A, 2B, and 2C.

[0095] Furthermore, when operating the gas purification apparatus 1 of this embodiment, if a pressurization process is included during operation, a pressure gauge (not shown) may be installed on each adsorption tower 2A, 2B, or 2C to determine the endpoint. The pressurization process refers to the process of increasing the pressure of each adsorption tower from the regeneration pressure to the adsorption pressure.

[0096] The number of adsorption towers provided in the gas purification device 1 of the present embodiment is not particularly limited as long as it is three or more, and an adsorption tower connecting path (see FIG. Figure 1 The adsorption tower connecting path L5) can obtain the same effect as the above effect.

[0097] Next, refer to Figures 2 to 4 , an example of the operation mode of the gas purification device 1 is described.

[0098] In accordance with Figure 4 When operating the gas refining device 1, for example, the valve timing diagram shown in FIG. Figure 2 The flow of raw gas G1, purified gas G2 and regeneration gas G3 shown in FIG is continued for 11 hours from the start of operation. Figure 2 As shown in FIG, the raw material gas G1 is supplied from the raw material gas introduction path L1 only to the adsorption tower 2A. The adsorption tower 2A performs an adsorption process on the raw material gas G1, thereby outputting a purified gas G2 as a product through the product gas output path L2.

[0099] Meanwhile, a regeneration process is performed in adsorption towers 2B and 2C simultaneously with the adsorption process in adsorption tower 2A. Specifically, a cooling process (regeneration process) for cooling adsorbent 6 is performed in adsorption tower 2B, and a heating process and a cooling process (regeneration process) for heating adsorbent 6 are performed in adsorption tower 2C.

[0100] exist Figure 2 In the operation process shown in FIG, the on-off valves V1a, V2a, V3b, V4c and the switching valves V5b, V5f are in the open state, and the other valves are in the closed state. Figure 2 In the operation shown in FIG, a portion of the regeneration gas G3 is introduced from the other end 2b side of the adsorption tower 2B via the regeneration gas introduction path L3, and the exhaust gas of the regeneration gas G3 discharged from the one end 2a side of the adsorption tower 2B is introduced from the other end 2b side into the adsorption tower 3C via the adsorption tower connecting path L5. Furthermore, the exhaust gas of the regeneration gas G3 discharged from the one end 2a side of the adsorption tower 3C is discharged to the outside of the adsorption tower 3C via the regeneration gas discharge path L4.

[0101] In addition, Figure 2In the operation process shown in FIG, only the heating portion 9 of the adsorption tower 2C that is performing the heating process (regeneration process) is turned on.

[0102] Next, from the start of operation for more than 11 hours to 12 hours, Figure 3 The flow of raw gas G1, purified gas G2 and regeneration gas G3 shown in FIG is carried out in the operation process. Figure 3 As shown in FIG, the raw gas G1 is continuously supplied from the raw gas introduction path L1 only to the adsorption tower 2A, and the adsorption tower 2A performs an adsorption process on the raw gas G1, thereby outputting the purified gas G2 as a product through the product gas output path L2.

[0103] On the other hand, the regeneration process is continued in adsorption towers 2B and 2C, but Figure 3 During the operation shown in Figure 2 The operation process shown in FIG2 is different from that in that the pressurization process is performed in the adsorption tower 2B, and the standby process is performed in the adsorption tower 2C.

[0104] exist Figure 3 In the operation process shown in , the on-off valves V1a, V2a, and V3b are in the open state, and the other valves are in the closed state. Figure 3 In the operation process shown in , the heating unit 9 included in the adsorption tower 2C is also shut down in the same manner as the other adsorption towers 2A and 2B.

[0105] When the gas purification device 1 of this embodiment is used for operation, for example, Figure 4 Based on the valve timing diagram shown, the above operation process can be implemented in rotation on the three adsorption towers 2A, 2B, and 2C.

[0106] [Gas purification method]

[0107] Next, the gas purification method of the present embodiment will be described in detail with reference to the same drawing, taking the above-mentioned operation using the gas purification device 1 of the present embodiment as an example.

[0108] The gas purification method of this embodiment is a method that uses at least three adsorption towers 2A, 2B, and 2C to adsorb and remove impurities from the raw gas G1 by TSA to obtain a purified gas G2 as a product, wherein the adsorption towers 2A, 2B, and 2C are filled with an adsorbent 6 for adsorbing impurities in the raw gas G1.

[0109] That is, the gas purification method of this embodiment repeatedly performs an adsorption process (1) and a regeneration process (2), wherein the adsorption process (1) is for removing impurities in the raw gas G1 by adsorption in the adsorption towers 2A, 2B, and 2C, and the regeneration process (2) is for removing the impurities adsorbed in the adsorption towers 2A, 2B, and 2C from the adsorption towers 2A, 2B, and 2C by heating the adsorption towers 2A, 2B, and 2C. At the same time, in this embodiment, the adsorption process (1) is performed in at least one of the three adsorption towers 2A, 2B, and 2C, and a portion of the purified gas G2 obtained by removing impurities from the raw gas G1 through the adsorption process (1) is used as a regeneration gas G3 for purging the adsorption towers 2B and 2C in the regeneration process (2) while performing gas purification.

[0110] Moreover, the gas purification method of this embodiment is the following method: that is, when at least two adsorption towers 2B and 2C among the three adsorption towers 2A, 2B, and 2C are subjected to the regeneration process (2), the regeneration gas G3 is sequentially circulated to each adsorption tower 2B and 2C that is subjected to the regeneration process (2).

[0111] That is, in this embodiment, an example is given in which the adsorption process (1) is performed in one adsorption tower 2A, and the regeneration process (2) is performed in two adsorption towers 2B and 2C at the same time.

[0112] (Adsorption process (1))

[0113] First, in the adsorption process (1), as described in the description of the gas purification device 1 of this embodiment, the on-off valves V1a, V2a, V3b, V4c and the switching valves V5b, V5f are in the open state, and the other valves are in the closed state. Figure 2 As in the operation process shown in FIG, the raw material gas G1 supplied from the raw material gas introduction path L1 is supplied to the adsorption tower 2A through the connecting pipe L6a.

[0114] The adsorbent 6 in the adsorption tower 2A removes impurities from the raw gas G1, generating a purified gas (product gas) G2. The purified gas G2 is then discharged as a product gas to the outside via the connecting pipe L7a and the product gas outlet path L2.

[0115] In the adsorption process (1), the components contained in the impurities removed by adsorption by the adsorbent, that is, the removal target in the gas purification method of this embodiment is not particularly limited, but is, for example, at least any one of H2O, CO2, O2, CO and hydrocarbons.

[0116] Furthermore, the other adsorption towers 2B and 2C also have the same structure as the adsorption tower 2A, and therefore can obtain the same effect as that of the adsorption tower 2A in the adsorption process (1).

[0117] (Regeneration process (2))

[0118] In the regeneration process (2), as described above, the on-off valves V1a, V2a, V3b, V4c and the switching valves V5b, V5f are in the open state, and the other valves are in the closed state, so that the adsorption process (1) is carried out in the adsorption tower 2A while the regeneration process (2) is carried out in the adsorption towers 2B and 2C.

[0119] The regeneration process (2) in the example described in this embodiment includes at least a heating process (2-1) for heating the adsorption tower 2C and a cooling process (2-2) for cooling the adsorption tower 2C after the heating process (2-1) to a temperature at which the adsorption process (1) can be performed. More specifically, when one adsorption tower 2C of the three adsorption towers 2A, 2B, and 2C is performing the heating process (2-1) and one adsorption tower 2B is performing the cooling process (2-2), the regeneration gas G3 is introduced into the adsorption tower 2B that is performing the cooling process (2-2). At the same time, the regeneration gas G3 discharged from the adsorption tower 2B that is performing the cooling process (2-2) is introduced into the adsorption tower 2C that is performing the heating process (2-1).

[0120] That is, in the regeneration process (2), while the refined gas G2 is being exported from the product gas outlet path L2 to the outside, a portion of the refined gas G2 is introduced into the adsorption tower 2B as the regeneration gas G3 via the regeneration gas inlet path L3 and the connecting pipe L7b, and at the same time, a portion of the refined gas G2 is introduced into the adsorption tower 2C as the regeneration gas G3 via the regeneration gas inlet path L3 and the connecting pipe L7c.

[0121] At this time, in the adsorption tower 2C, the heating unit 9 is activated to heat the shell 5, thereby indirectly (auxiliarily) heating the regeneration gas G3 and adsorbent 6 in the shell 5. On the other hand, in the adsorption tower 2B, the regeneration gas G3 extracted from the regeneration gas introduction path L3 is introduced into the adsorption tower 2B, thereby cooling the adsorbent 6 in the shell 5.

[0122] Moreover, in the regeneration process (2) of this embodiment, the exhaust gas of the regeneration gas G3 discharged from one end 2a side of the adsorption tower 2B is introduced into the adsorption tower 2C from the other end 2b side via the connecting pipe L6b, the adsorption tower connecting path L5 and the connecting pipe L7C.

[0123] As described above, the adsorbent 6 within the adsorption tower 2C (housing 5) is heated to approximately 100-400°C using the regeneration gas G3 and the heating unit 9, thereby desorbing impurities from the adsorbent 6. The impurities desorbed from the adsorbent 6 are then mixed with the regeneration gas G3 and discharged to the outside via the connecting pipe L6c and the regeneration gas desorption path L4.

[0124] After the impurities adsorbed on the adsorbent 6 are sufficiently removed in the heating process (2-1), the operation of the heating unit 9 is stopped, the on-off valves V1a, V2a, and V3b are opened, and the other valves are closed.

[0125] Therefore, as in Figure 3 As shown in the operation process, the raw gas G1 continues to be supplied only to the adsorption tower 2A from the raw gas inlet path L1, and the adsorption tower 2A performs the adsorption process (1) on the raw gas G1, thereby continuing to output the purified gas G2 as the product through the product gas outlet path L2.

[0126] On the other hand, the regeneration process (2) is also continued in the adsorption towers 2B and 2C, but Figure 2 The operation process shown in FIG2 is different from that in which a pressurizing process is implemented in the adsorption tower 2B and a standby process is implemented in the adsorption tower 2C.

[0127] In the gas purification method of the present embodiment, for example, the above-mentioned operation process can be carried out in rotation with respect to the three adsorption towers 2A, 2B, and 2C.

[0128] According to the gas purification method of this embodiment, when the regeneration process (2) is carried out in at least two adsorption towers 2B and 2C, by sequentially circulating the regeneration gas G3 to each of the adsorption towers 2B and 2C, the flow rate of the regeneration gas G3 required for heating and cooling the adsorption towers 2B and 2C can be reduced. Furthermore, the flow rate of the exhaust gas of the regeneration gas G3 discharged from the adsorption towers 2B and 2C during the regeneration process (2) can be reduced. As a result, the amount of the exhaust gas of the regeneration gas G3 contained in the purified gas G2 can be reduced, and the recovery rate of the product gas can be improved.

[0129] Furthermore, in the gas purification method of this embodiment, before the regeneration gas G3 discharged from the adsorption tower 2B undergoing the cooling process (2-2) is introduced into the adsorption tower 2C undergoing the heating process (2-1), the temperature of the regeneration gas G3 is preferably cooled to 150°C or less.

[0130] <Second embodiment>

[0131] Next, a gas purification method and a gas purification device according to a second embodiment of the present invention will be described below.

[0132] In the following description, the same reference numerals may be used to describe the same (or similar) structures as those of the gas purification apparatus 1 of the first embodiment, and detailed descriptions thereof may be omitted. In the following description, the same procedures and conditions as those of the gas purification method of the first embodiment may also be omitted.

[0133] Figure 5 It is a system diagram showing the general configuration of a gas purification device 1A according to the second embodiment.

[0134] Figure 7 To express Figure 5 The valve timing diagram of the opening and closing actions of each valve for controlling the flow of the raw gas G1, the purified gas G2 and the regeneration gas G3 in the gas purification device 1A is shown. Figure 7 In the diagram, the time period marked with a slash in the valve row indicates that the valve is in an open state, and the time period marked with a dot in the heating section row indicates that the heating section is operating and heating the adsorption tower.

[0135] Figure 5 The gas purification device 1A of the second embodiment shown in the figure comprises adsorption towers 2A, 2B, 2C, a raw gas inlet path L1, a product gas outlet path L2, a regeneration gas inlet path L3, and a regeneration gas outlet path L4. Figure 1 The same is true for the gas purification device 1 of the first embodiment shown.

[0136] On the other hand, the gas purification apparatus 1A of the second embodiment is provided with separate adsorption tower connecting paths (adsorption tower connecting pipes) L5A1, L5A2, and L5A3, each of which connects one end 2a of any one of the adsorption towers 2A, 2B, and 2C to the other end 2b of the other adsorption towers via connecting pipes L6a, L6b, and L6c or connecting pipes L7a, L7b, and L7c. This point differs from the gas purification apparatus 1 of the first embodiment, which is provided with the adsorption tower connecting path L5 that connects all three adsorption towers 2A, 2B, and 2C in a ring shape.

[0137] That is Figure 5 In the illustrated gas purification apparatus 1A, one end 2a of the adsorption tower 2C and the other end 2b of the adsorption tower 2A are connected by an adsorption tower connecting path L5A1 via connecting pipes L6c and L7a, respectively.

[0138] Furthermore, one end 2a of the adsorption tower 2A and the other end 2b of the adsorption tower 2B are connected by an adsorption tower connecting path L5A2 via connecting pipes L6a and L7b, respectively.

[0139] Furthermore, one end 2a of the adsorption tower 2B and the other end 2b of the adsorption tower 2c are connected by an adsorption tower connecting path L5A3 via connecting pipes L6b and L7c, respectively.

[0140] In such Figure 5 When operating the gas purification device 1A having the adsorption tower connection paths L5A1, L5A2, and L5A3 shown in FIG, for example, Figure 7 Each operation process is implemented using the valve timing diagram shown. Specifically, in the gas purification apparatus 1A of the second embodiment, the switching valves V5a, V5b, and V5c provided on the adsorption tower connecting paths L5A1, L5A2, and L5A3 can be opened and closed at predetermined timings, similarly to the gas purification apparatus 1 of the first embodiment. Thus, the gas purification apparatus 1A can also implement the following operation process: during this operation process, when at least two of the three adsorption towers 2A, 2B, and 2C are undergoing the regeneration process (2), the regeneration gas G3 is sequentially circulated to each of the adsorption towers 2B and 2C undergoing the regeneration process (2).

[0141] Furthermore, in the operation of the gas purification method using the gas purification apparatus 1A of this embodiment, after the heating process (2-1) of the regeneration process (2) is completed and after the cooling process (2-2) begins, the high-temperature regeneration gas G3 (gas having a temperature corresponding to the heating temperature in the adsorption tower) is discharged from the outlet side of the adsorption towers 2A, 2B, and 2C. Therefore, in the gas purification apparatus 1A of this embodiment, Figure 5 The on-off valves V4a, V4a, V4b and the switching valves V5a, V5b, V5c shown in FIG need to be heat-resistant valves that can be used at the heating temperature of the adsorption towers 2A, 2B, 2C.

[0142] According to the gas purification apparatus 1A of this embodiment, since the adsorption tower connecting paths L5A1, L5A2, and L5A3 of the above-described structure are provided, similarly to the gas purification apparatus 1 of the first embodiment, when the regeneration process (2) of the adsorbent 6 is being performed in at least two of the three adsorption towers 2A, 2B, and 2C, the regeneration gas G3 can be sequentially circulated to each adsorption tower performing the regeneration process (2). This allows the regeneration gas G3 to be efficiently utilized in the regeneration process (2) without requiring a compressor or the like. Furthermore, similarly to the above, the flow rate of the regeneration gas G3 required for heating and cooling the adsorption towers 2A, 2B, and 2C can be reduced, thereby also reducing the flow rate of the exhaust gas of the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C. Consequently, the amount of exhaust gas of the regeneration gas G3 contained in the purified gas G2 as the product gas can be reduced, thereby improving the recovery rate of the product gas.

[0143] <Third embodiment>

[0144] Next, a gas purification method and a gas purification device according to a third embodiment of the present invention will be described below.

[0145] In the following description, the same reference numerals may be used to describe the same (or similar) structures as those of the gas purification apparatuses 1 and 1A of the first and second embodiments, and detailed description thereof may be omitted. In the following description, the same procedures and conditions as those of the gas purification methods of the first and second embodiments may also be omitted.

[0146] Figure 6 It is a system diagram showing the general configuration of a gas purification device 1B according to the third embodiment.

[0147] Figure 7 To express Figure 6 The valve timing diagram of the opening and closing actions of each valve for controlling the flow of the raw gas G1, the purified gas G2 and the regeneration gas G3 in the gas purification device 1B is shown. Figure 7 In the diagram, the time period marked with a slash in the valve row indicates that the valve is in an open state, and the time period marked with a dot in the heating section row indicates that the heating section is operating and heating the adsorption tower.

[0148] Figure 6 The gas purification device 1B of the third embodiment shown in the figure comprises adsorption towers 2A, 2B, 2C, a raw gas inlet path L1, a product gas outlet path L2, a regeneration gas inlet path L3, and a regeneration gas outlet path L4, and further comprises adsorption tower connecting paths L5A1, L5A2, L5A3 for connecting one end 2a of any one of the adsorption towers 2A, 2B, 2C to the other end 2b of the other adsorption tower. Figure 5 The same is true for the gas purification device 1A of the second embodiment shown. Figure 6 The gas purification device 1B of the third embodiment shown can be used, for example, according to Figure 7 The valve timing diagram shown in the figure implements each operation process, which is also consistent with the Figure 5 The same applies to the gas purification device 1A of the second embodiment shown.

[0149] On the other hand, the gas refining device 1B of the third embodiment is different from the gas refining device 1A of the second embodiment in that heat exchangers 7a, 7b, 7c are provided on the primary side of the switching valves V5a, V5b, V5c respectively provided on the adsorption tower connecting paths L5A1, L5A2, L5A3 for cooling the regeneration gas G3 flowing in the adsorption tower connecting paths L5A1, L5A2, L5A3.

[0150] As Figure 3The heat exchangers 7a, 7b, and 7c shown in FIG. 5 may be finned tube, bellows, or plate fin type heat exchangers, but the type of heat exchanger and the cooling method (air cooling or water cooling) are not particularly limited.

[0151] In the operation of the gas purification method using the gas purification apparatus 1B of the present embodiment, the temperature of the high-temperature regeneration gas G3 discharged from the outlet side of the adsorption towers 2A, 2B, and 2C after the completion of the heating process (2-1) in the regeneration process (2) and the start of the cooling process (2-2) is preferably reduced to 150° C. or less, more preferably to 80° C. or less, by the heat exchangers 7 a, 7 b, and 7 c. This is because if the outlet temperature of the heat exchangers 7 a, 7 b, and 7 c exceeds 150° C., it is necessary to use expensive all-metal diaphragm valves (e.g., FWB-71 series manufactured by Fujikin Co., Ltd.) for the switching valves V5 a, V5 b, and V5 c disposed on the outlet side of the heat exchangers 7 a, 7 b, and 7 c.

[0152] On the other hand, the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C is cooled to a temperature below 150°C by heat exchangers 7a, 7b, and 7c, so that cheap valves such as metal diaphragm valves using polyimide or PFA as the valve seat material (for example, FPR-ND-71-6.35-PI manufactured by Fujikin Co., Ltd.) can be used.

[0153] Furthermore, when the regeneration gas G3 discharged from the adsorption towers 2A, 2B, 2C is cooled to a temperature below 80°C by the heat exchangers 7a, 7b, 7c, a cheaper valve such as a general-purpose metal diaphragm valve (for example, FPR-ND-71-6.35 manufactured by Fujikin Co., Ltd.) can be used.

[0154] Furthermore, the all-metal diaphragm valve is not only expensive, but also, due to its structural characteristics, even if a small amount of dust enters, it is easy to cause internal leakage, in which gas continues to flow even when the valve is closed. This may cause problems in the gas purification device, so it is preferably avoided.

[0155] <Fourth embodiment>

[0156] Next, a gas purification method and a gas purification device according to a fourth embodiment of the present invention will be described below.

[0157] In the following description, components identical (or similar) to the gas purification apparatuses 1, 1A, and 1B of the first to third embodiments may be described using the same reference numerals, and detailed description thereof may be omitted. Furthermore, in the following description, components identical (or similar) to the gas purification methods of the first to third embodiments may be described using the same reference numerals, and detailed description thereof may be omitted.

[0158] Figure 8It is a system diagram showing the general configuration of a gas purification device 1C according to the fourth embodiment.

[0159] Figure 8 The gas purification device 1C of the fourth embodiment shown in the figure comprises adsorption towers 2A, 2B, and 2C, a raw gas inlet path L1, a product gas outlet path L2, a regeneration gas inlet path L3, and a regeneration gas outlet path L4, and further comprises adsorption tower connecting paths L5A1, L5A2, and L5A3 for connecting one end 2a of any one of the adsorption towers 2A, 2B, and 2C to the other end 2b of the other adsorption tower. Figure 5 The same is true for the gas purification device 1A of the second embodiment shown. Figure 8 The gas purification device 1C of the fourth embodiment shown can be used, for example, according to Figure 7 The valve timing diagram shown in the figure implements each operation process, which is also consistent with the Figure 5 The same applies to the gas purification device 1A of the second embodiment shown.

[0160] On the other hand, the gas refining device 1C of the fourth embodiment is different from the gas refining device 1A of the second embodiment in that heat exchangers 71a, 71b, 71c are provided between the adsorption towers 2A, 2B, 2C and the on-off valves V4a, V4b, V4c provided on the regeneration gas outlet path L4 for cooling the regeneration gas G3 flowing in the regeneration gas outlet path L4.

[0161] Furthermore, the gas refining device 1C of the fourth embodiment is different from the gas refining device 1A of the second embodiment in that drain traps 8a, 8b, 8c are provided inside the heat exchangers 71a, 71b, 71c provided on the regeneration gas outlet path L4 or on the regeneration gas outlet path L4 on the outlet side of these heat exchangers 71a, 71b, 71c. Figure 8 2 shows an example in which drain traps 8a, 8b, and 8c are provided at the terminal ends of three drain pipes L41, which are pipes introduced from the regeneration gas outlet path L4.

[0162] According to the gas purification apparatus 1C of this embodiment, heat exchangers 71a, 71b, and 71c are provided in the regeneration gas outlet path L4 between the adsorption towers 2A, 2B, and 2C and the on-off valves V4a, V4b, and V4c, respectively. This eliminates the need for expensive heat-resistant valves for the on-off valves V4a, V4b, and V4c, as described above. Specifically, the high-temperature regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C is cooled by the heat exchangers 71a, 71b, and 71c. This allows the use of inexpensive, general-purpose valves for the on-off valves V4a, V4b, and V4c, thereby reducing apparatus costs.

[0163] Furthermore, the gas purification apparatus 1C of this embodiment, provided with the drain traps 8a, 8b, and 8c of the aforementioned configuration, achieves the following advantages. Specifically, the regeneration gas G3 discharged from the adsorption tower during the heating process (2-1) contains moisture desorbed from the adsorbent 6. Therefore, cooling by the heat exchangers 71a, 71b, and 71c generates a large amount of condensed water. The generation of such a large amount of condensed water could potentially clog the regeneration gas outlet path L4. However, by employing the configuration of the gas purification apparatus 1C of this embodiment, provided with the drain traps 8a, 8b, and 8c, this clogging of the regeneration gas outlet path L4 can be prevented.

[0164] <Effects>

[0165] As described above, the gas purification method using the gas purification apparatuses 1, 1A, 1B, and 1C of this embodiment employs the following method: As described above, when at least two of the three adsorption towers 2A, 2B, and 2C are undergoing the regeneration process (2), the regeneration gas G3 is sequentially passed through the adsorption towers 2B and 2C undergoing the regeneration process (2). By adopting this method, the flow rate of the regeneration gas G3 required for heating and cooling the adsorption towers 2A, 2B, and 2C can be reduced, and the flow rate of the exhaust gas of the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C during the regeneration process (2) can also be reduced. Consequently, the amount of exhaust gas of the regeneration gas G3 contained in the purified gas G2 can be reduced, and the recovery rate of the product gas can be improved.

[0166] The gas purification apparatus of the present invention also employs a structure in which an adsorption tower connecting path L5 is provided between the three adsorption towers 2A, 2B, and 2C. This adsorption tower connecting path L5 connects one end 2a of each adsorption tower 2A, 2B, and 2C connected to the regeneration gas outlet path L4 with the other end 2b connected to the regeneration gas inlet path L3. Furthermore, switching valves V5a, V5b, and V5c are provided on the adsorption tower connecting path L5. This structure, as described above, reduces the flow rate of the regeneration gas G3 required for heating and cooling the adsorption towers 2A, 2B, and 2C, and also reduces the flow rate of the exhaust gas of the regeneration gas G3 discharged from the adsorption towers 2A, 2B, and 2C. Furthermore, the regeneration gas G3 can be efficiently utilized without requiring a compressor (booster) or the like. Consequently, a gas purification apparatus 1, 1A, 1B, or 1C is provided that reduces the amount of exhaust gas of the regeneration gas G3 contained in the purified gas G2 and improves the recovery rate of the product gas.

[0167] In addition, the regeneration gas G3 that is heated by taking heat from the adsorbent 6 and is passed into the adsorption tower that is implementing the cooling process (2-2) included in the regeneration process (2) is passed into the adsorption tower that is implementing the heating process (2-1). Therefore, it is possible to reduce the load of the heating part 9 in the heating process (2-1) while shortening the heating time in the heating process (2-1).

[0168] <Other forms>

[0169] While the above embodiment describes an example of the gas purification method and gas purification apparatus of the present invention, the present invention is not limited to the above embodiment. The various structures and combinations thereof in the above embodiment are merely examples, and additions, omissions, substitutions, and other modifications may be made without departing from the spirit of the present invention.

[0170] For example, in the above embodiments, the gas purification device 1, 1A, 1B, 1C having three adsorption towers 2A, 2B, 2C is illustrated, but the number of adsorption towers installed is not limited thereto. For example, a device structure and method having four or more adsorption towers may also be adopted.

[0171] Example

[0172] Hereinafter, the gas purification method and gas purification apparatus of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples and can be implemented with appropriate modifications without departing from the spirit of the invention.

[0173] <Purification Conditions and Regeneration Conditions and Structure of Gas Purification Device>

[0174] In this embodiment, the Figure 1 The three-column switching TSA method shown in FIG. 1 was used to purify hydrogen using the gas purification device 1 having the adsorption column connecting path L5 and having the structure of the present invention, thereby verifying the effect of the present invention (Example).

[0175] In addition, in this example, as relative to Figure 1 As a comparative example of the three-tower switching gas purification apparatus 1 shown, a conventional two-tower switching gas purification apparatus disclosed in Japanese Patent Application Laid-Open No. 2020-65984 and not having an adsorption tower connecting path was prepared and evaluated under the same conditions (comparative example).

[0176] In this example, to obtain purified hydrogen, a raw material gas mainly composed of hydrogen and containing about 2800 ppm of water as an impurity was used. The amount of regeneration gas contained in the purified gas was compared between the example and the comparative example.

[0177] [Gas purification / regeneration conditions]

[0178] The composition of the raw material gas and the gas purification / regeneration conditions in Examples and Comparative Examples are shown below in detail.

[0179] (1) Composition of raw gas: H2+H2O

[0180] (2) H2O concentration: 2800 ppm (removal target component)

[0181] (3) Flow rate: 100Nm 3 / h

[0182] (4) Pressure: 800kPaG

[0183] (5) Temperature: 25°C

[0184] (6) Adsorbent: Zeolite (synthetic)

[0185] (7) Regeneration temperature: 300°C

[0186] (8) Regeneration pressure: atmospheric pressure

[0187] In both the examples and the comparative examples, an adsorption tower having an inner cylinder (shell) made of SUS304 (size: 80A-Sch10S) and a height of 1330 mm was used.

[0188] As described above, synthetic zeolite was used as the adsorbent, and the filling height (the height of the adsorbent layer) was 1240 mm.

[0189] [Operation sequence]

[0190] (Example)

[0191] In the examples, a three-tower switching type gas purification apparatus was used to adsorb water and other impurities from the raw gas in the following procedure to obtain hydrogen as a purified gas.

[0192] First, according to Figure 4 The valve timing diagram shown is as follows Figure 2 In the operation process shown in FIG, the raw gas G1 is supplied from the raw gas introduction path L1 to the adsorption tower 2A to perform the adsorption process, and the purified gas G2 is discharged through the product gas discharge path L2.

[0193] In addition, a regeneration process is performed in adsorption towers 2B and 2C simultaneously with the adsorption process in adsorption tower 2A. At this time, a cooling process (regeneration process) for cooling the adsorbent 6 is performed in adsorption tower 2B, and a heating process and a cooling process (regeneration process) for heating the adsorbent 6 are performed in adsorption tower 2C. Specifically, while a portion of the regeneration gas G3 is introduced from the other end 2b of adsorption tower 2B via the regeneration gas introduction path L3, the exhaust gas of the regeneration gas G3, which is discharged from one end 2a of adsorption tower 2B, is introduced into adsorption tower 3C from the other end 2b via the adsorption tower connecting path L5. Furthermore, the exhaust gas of the regeneration gas G3, which is discharged from one end 2a of adsorption tower 3C, is discharged to the outside of adsorption tower 3C via the regeneration gas discharge path L4. Furthermore, during this operation, only the heating section 9 of adsorption tower 2C, which is performing the heating process (regeneration process), is turned on.

[0194] Then, follow Figure 3 In the operation process shown in FIG, while continuing to implement the adsorption process in the adsorption tower 2A, the pressurization process is implemented in the adsorption tower 2B, and the standby process is implemented in the adsorption tower 2C.

[0195] In the embodiment, according to Figure 4 As shown in the valve timing diagram, the above operation process is implemented in rotation for the three adsorption towers 2A, 2B, and 2C.

[0196] (Comparative Example)

[0197] A gas purification apparatus of a comparative example using a double-tower switching type adsorbs water and the like as impurities from a raw material gas in the following procedure, and obtains hydrogen as a purified gas.

[0198] First, the raw gas is continuously fed into one adsorption tower to be converted into purified gas. Meanwhile, in the other adsorption tower, a portion of the purified gas obtained from one adsorption tower is used as regeneration gas and circulated into the other adsorption tower. Furthermore, the other adsorption tower is heated by the heating unit at this time.

[0199] Next, in one adsorption tower, under the same conditions as above, while the raw gas is purified in one adsorption tower, in another adsorption tower, a portion of the purified gas obtained from one adsorption tower is used as regeneration gas and circulated into the other adsorption tower to cool the other adsorption tower.

[0200] Then, the above processes are switched and rotated between one adsorption tower and another adsorption tower.

[0201] <Evaluation Results>

[0202] Table 1 below shows the operation processes of the two-tower switching type (comparative example) and the three-tower switching type (example) and the comparison results of the amount of regeneration gas contained in the purified gas (product gas) in these examples and comparative examples.

[0203] In addition, the recovery rates shown in the following Table 1 are values ​​expressed by the following formula.

[0204] {(Supply amount of raw gas per cycle) - (Discharge amount of regeneration gas per cycle) / (Supply amount of raw gas per cycle)}

[0205] [Table 1]

[0206] TSA method Dual tower switching Three-tower switching type (this invention) Switching time 24h 12h Raw gas flow <![CDATA[100Nm 3 / h]]> <![CDATA[100Nm 3 / h]]> Adsorbent dose 30kg / tower 20kg / tower Heating process 9h 6h Cooling process 11h 16h Charging / standby process 4h 1h Refining process 24h 12h Average gas flow rate per cycle <![CDATA[3.3Nm 3 / h]]> <![CDATA[1.8Nm 3 / h]]> Recovery rate 96.7％ 98.2％

[0207] As shown in Table 1, in the comparative example using a double-tower switching-type gas purification apparatus having a conventional structure, the recovery rate of the purified gas after subtracting the regeneration gas from the purified gas was 96.7%.

[0208] In contrast, it can be confirmed that in an embodiment of a gas purification device 1 using the structure of the present invention (i.e., a three-tower switching TSA method and an adsorption tower connecting path L5), the recovery rate of the purified gas after subtracting the regeneration gas from the purified gas is 98.2%, which is an improved recovery rate compared to the comparative example.

[0209] From the results of this embodiment as described above, it can be seen that by applying the present invention, the flow rate of the regeneration gas required for heating and cooling the adsorption tower can be reduced, and the flow rate of the exhaust gas of the regeneration gas discharged from the adsorption tower during the regeneration process can be reduced, thereby reducing the amount of exhaust gas of the regeneration gas contained in the refined gas and improving the recovery rate of the refined gas as a product.

[0210] Industrial applicability

[0211] The gas purification method and gas purification apparatus of the present invention efficiently utilize regeneration gas without requiring a compressor, and can reduce the amount of regeneration gas discharged, thereby improving the recovery rate of product gas. Therefore, the present invention is particularly suitable for applications such as purification of expensive rare gases and for use in gas generation systems such as hydrogen generators, where the amount of gas generated (raw gas) is limited and the amount of product gas (usable gas) is desired to be increased.

[0212] Description of Reference Numerals

[0213] 1. 1A, 1B, 1C gas refining units

[0214] 2A, 2B, 2C adsorption towers

[0215] 2a One end

[0216] 2b The other end

[0217] 5. Housing

[0218] 6 Adsorbent

[0219] 9 Heating unit

[0220] L1 Raw material gas introduction path (raw material gas introduction pipe)

[0221] L2 product gas outlet path (product gas outlet pipeline)

[0222] L3 regeneration gas inlet path (regeneration gas inlet pipe)

[0223] L4 regeneration gas outlet path (regeneration gas exhaust pipe)

[0224] L5, L5A1, L5A2, L5A3 adsorption tower connection path (adsorption tower connection pipe)

[0225] L41 discharge pipe

[0226] L6a, L6b, L6c, L7a, L7b, L7c connecting pipes

[0227] V1a, V1b, V1c, V2a, V2b, V2c, V3a, V3b, V3c, V4a, V4b, V4c on / off valves

[0228] V5a, V5b, V5c, V5d, V5e, V5f switching valves

[0229] Heat exchangers 7a, 7b, 7c, 71a, 71b, 71c

[0230] 8a, 8b, 8c drainage traps

[0231] NV1 Regeneration Gas Flow Control Valve

[0232] G1 raw gas

[0233] G2 refined gas

[0234] G3 regeneration gas

Claims

1. A gas purification method, characterized in that: At least three adsorption towers filled with an adsorbent for adsorbing impurities in a raw gas are used, and an adsorption process and a regeneration process are repeatedly performed by temperature swing adsorption. The adsorption process removes the impurities in the raw gas by adsorption in the adsorption towers, and the regeneration process removes the impurities adsorbed in the adsorption towers by heating the adsorption towers. In the gas purification method, the adsorption process is performed in at least one of the three adsorption towers, and a portion of the purified gas obtained by removing the impurities from the raw gas during the adsorption process and discharged from the adsorption tower in the adsorption process is used as a regeneration gas for purging the adsorption towers in the regeneration process to perform gas purification. When at least two of the three adsorption towers are undergoing the regeneration process, the regeneration gas is sequentially circulated to the respective adsorption towers undergoing the regeneration process.

2. The gas purification method according to claim 1, characterized in that: The regeneration process at least includes a heating process of heating the adsorption tower and a cooling process of cooling the adsorption tower after the heating process to a temperature at which the adsorption process can be performed. When at least one of the three adsorption towers is implementing the heating process and at least one of the adsorption towers is implementing the cooling process, the regeneration gas is introduced into the adsorption tower that is implementing the cooling process, and at the same time, the regeneration gas discharged from the adsorption tower that is implementing the cooling process is introduced into the adsorption tower that is implementing the heating process.

3. The gas purification method according to claim 1 or 2, characterized in that: Before the regeneration gas discharged from the adsorption tower undergoing the cooling process is introduced into the adsorption tower undergoing the heating process, the temperature of the regeneration gas is cooled to 150° C. or less.

4. The gas purification method according to claim 1 or 2, characterized in that: The component contained in the impurities adsorbed and removed by the adsorbent is at least any one of H 2 O, CO 2 , O 2 , CO, and hydrocarbons.

5. A gas purification device for removing impurities from raw gas by adsorption to generate purified gas, characterized in that: include: at least three adsorption towers filled with an adsorbent for adsorptive removal of the impurities from the raw gas; a raw gas inlet pipe and a regeneration gas outlet pipe respectively connected to one end of the adsorption tower, wherein the raw gas inlet pipe is used to introduce the raw gas into the adsorption tower, and the regeneration gas outlet pipe is used to discharge the regeneration gas introduced into the adsorption tower from the adsorption tower; a product gas outlet pipe and a regeneration gas inlet pipe respectively connected to the other end of the adsorption tower, wherein the product gas outlet pipe is used to discharge the refined gas from the adsorption tower, and the regeneration gas inlet pipe is used to introduce the regeneration gas into the adsorption tower; On the raw gas inlet pipe, the regeneration gas outlet pipe, the product gas outlet pipe and the regeneration gas inlet pipe, an on-off valve is respectively provided on one end side or the other end side of the adsorption tower; and a heating unit provided on the adsorption tower and used to heat the adsorbent or the regeneration gas; An adsorption tower connecting pipe is provided between the three adsorption towers, and the adsorption tower connecting pipe connects the one end of the adsorption tower connected to the regeneration gas exhaust pipe and the other end connected to the regeneration gas inlet pipe, and a switching valve is provided on the adsorption tower connecting pipe.

6. The gas purification device according to claim 5, characterized in that: The adsorption tower connecting pipe is configured to connect all three adsorption towers into a ring shape.

7. The gas purification device according to claim 5 or 6, characterized in that: The switching valve provided on the adsorption tower connecting pipe has a heat-resistant temperature that is at least equal to or higher than the heating temperature of the adsorption tower.

8. The gas purification device according to claim 5 or 6, characterized in that: A heat exchanger for cooling the regeneration gas flowing through the adsorption tower connecting pipe is provided on the primary side of the switching valve provided on the adsorption tower connecting pipe.

9. The gas purification device according to claim 5 or 6, characterized in that: A heat exchanger for cooling the gas flowing through the regeneration gas exhaust pipe is provided between the adsorption tower and the on-off valve provided on the regeneration gas exhaust pipe.

10. The gas purification device according to claim 9, characterized in that: A drain trap is provided inside the heat exchanger provided on the regeneration gas exhaust pipe or on the regeneration gas exhaust pipe on the outlet side of the heat exchanger.

11. The gas purification device according to claim 5 or 6, characterized in that: The component contained in the impurities adsorbed and removed by the adsorbent is at least any one of H 2 O, CO 2 , O 2 , CO, and hydrocarbons.

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