Air purification device and air purification method

Description

[Technical field]

[0001] The present invention relates to an air purification device and an air purification method. [Background technology]

[0002] Conventionally, air purification devices are known that use a temperature swing adsorption method to remove impurities from raw air containing impurities such as water and carbon dioxide to extract purified air. Patent Document 1 discloses this type of air purification device. The air purification device described in Patent Document 1 is equipped with two adsorption towers. In the air purification device of Patent Document 1, an air purification process for purifying raw air is performed in one adsorption tower, and a regeneration process for regenerating the adsorbent is performed in the other adsorption tower. In the air purification device of Patent Document 1, the above-mentioned air purification process and regeneration process are alternately performed between the two adsorption towers, thereby continuously purifying the air as a whole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-80669 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when air purification processing and regeneration processing are alternately switched between two adsorption towers as in the air purification device described in Patent Document 1, the oxygen concentration of the purified air may vary before and after the switch. Specifically, the oxygen concentration of the purified air purified in one of the adsorption towers immediately after switching from regeneration processing to air purification processing may differ from the oxygen concentration of the purified air purified in the other adsorption tower that had been performing the air purification processing until immediately before the switch.

[0005] One of the adsorption columns that is switched from the regeneration process to the air purification process is pressure-equalized with the other adsorption column that is performing the air purification process, for example by being pressurized just before the switch. This allows the execution of the air purification process to be continuously switched from the other adsorption column to one of the adsorption columns. However, due to the above-mentioned pressure equalization, adsorption of oxygen or nitrogen to the adsorbent or desorption from the adsorbent may occur in one of the adsorption columns. In other words, the above-mentioned pressure equalization is performed in one of the adsorption columns just before the switch from the regeneration process to the air purification process, which may cause the oxygen concentration to fluctuate before and after the switch.

[0006] This fluctuation in oxygen concentration occurs immediately after switching, but is eliminated as the air purification process progresses in one of the adsorption columns. However, there are cases where the occurrence of the above-mentioned fluctuation in oxygen concentration before and after switching is undesirable, such as the air used in an exposure tool, which is one type of semiconductor manufacturing equipment.

[0007] The present invention aims to provide an air purification device and an air purification method that can suppress fluctuations in oxygen concentration in purified air that occur before and after switching when air purification process and regeneration process are alternately switched between two adsorption columns. [Means for solving the problem]

[0008] An air purifying apparatus according to a first aspect of the present invention comprises: (1) 1. An air purification apparatus for purifying a feed air by removing impurities from the feed air by a temperature swing adsorption method, comprising: The method includes the steps of: providing two adsorption columns each filled with an adsorbent capable of adsorbing the impurities, and capable of alternately performing an air purification process for purifying the raw air using the adsorbent, and a regeneration process for regenerating the adsorption capacity of the adsorbent; The air purification device is such that one of the two adsorption columns in which the regeneration process is being performed is switched to perform the air purification process after a flow purge is performed in a pressure equalization state with the other of the two adsorption columns in which the air purification process is being performed.

[0009] An air purifying apparatus according to one embodiment of the present invention comprises: (2) a regeneration gas supply path capable of supplying a regeneration gas to the two adsorption columns in the regeneration treatment; an exhaust path capable of exhausting exhaust gas in a state in which the impurities desorbed from the adsorbent in the regeneration process are mixed with the regeneration gas from the two adsorption columns; This is an air purification apparatus as described in (1) above, wherein in the regeneration process, before the one adsorption tube is brought into a pressure-equal state with the other adsorption tube, the exhaust gas is exhausted from the one adsorption tube through the exhaust path, and after the one adsorption tube is brought into a pressure-equal state with the other adsorption tube, the flow purge is performed in which a flow purge gas is exhausted from the one adsorption tube through the exhaust path.

[0010] An air purifying apparatus according to one embodiment of the present invention comprises: (3) a flow rate adjusting unit capable of adjusting a flow rate is provided in the exhaust path, In the air purification device according to (2) above, the one adsorption column is brought into a pressure equal state with the other adsorption column by operating the flow rate adjustment unit.

[0011] An air purifying apparatus according to one embodiment of the present invention comprises: (4) The exhaust path is an exhaust gas path capable of exhausting the exhaust gas from the one of the adsorption columns; a flow purge gas passage capable of discharging the flow purge gas from the one of the adsorption columns when the flow purge is performed, The flow rate adjusting unit is A first opening / closing valve provided in the exhaust gas path; a second opening / closing valve provided in the flow purge gas path and having a flow rate in an open state smaller than that of the first opening / closing valve; The air purification device according to (3) above, wherein the one adsorption column is made to be in a pressure equal state with the other adsorption column by manipulating the opening and closing states of the first opening and closing valve and the second opening and closing valve.

[0012] The method for purifying air according to a second aspect of the present invention comprises the steps of: (5) 1. A method for purifying feed air by removing impurities from the feed air using a temperature swing adsorption method, comprising: a continuous purification process in which an air purification process for purifying the raw air using an adsorbent capable of adsorbing the impurities and a regeneration process for regenerating the adsorption capacity of the adsorbent are alternately performed by two adsorption columns filled with the adsorbent, This is an air purification method, wherein in the continuous purification process, one of the two adsorption columns in which the regeneration process is being performed is switched to perform the air purification process after a flow purge is performed in a pressure equalization state with the other of the two adsorption columns in which the air purification process is being performed.

[0013] As one embodiment of the present invention, a method for purifying air comprises the steps of: (6) a regeneration gas supply path capable of supplying a regeneration gas to the two adsorption columns in the regeneration treatment; an exhaust path capable of exhausting exhaust gas in a state in which the impurities desorbed from the adsorbent in the regeneration process are mixed with the regeneration gas from the two adsorption columns; This is an air purification method as described in (5) above, wherein in the regeneration process, before the one adsorption tube is brought into a pressure-equal state with the other adsorption tube, the exhaust gas is exhausted from the one adsorption tube through the exhaust path, and after the one adsorption tube is brought into a pressure-equal state with the other adsorption tube, the flow purge is performed in which a flow purge gas is exhausted from the one adsorption tube through the exhaust path.

[0014] As one embodiment of the present invention, a method for purifying air comprises the steps of: (7) a flow rate adjusting unit capable of adjusting a flow rate is provided in the exhaust path, The air purification method according to (6) above, wherein the one adsorption column is brought into a pressure equal state with the other adsorption column by operating the flow rate adjustment unit.

[0015] As one embodiment of the present invention, a method for purifying air comprises the steps of: (8) The exhaust path is an exhaust gas path capable of exhausting the exhaust gas from the one of the adsorption columns; a flow purge gas passage capable of discharging the flow purge gas from the one of the adsorption columns when the flow purge is performed, The flow rate adjusting unit is A first opening / closing valve provided in the exhaust gas path; a second opening / closing valve provided in the flow purge gas path and having a flow rate in an open state smaller than that of the first opening / closing valve; This is an air purification method described in (7) above, wherein the one adsorption column is made to be in a pressure equal state with the other adsorption column by manipulating the opening and closing states of the first opening and closing valve and the second opening and closing valve. Effect of the Invention

[0016] According to the present invention, an air purification device and an air purification method can be provided that, when air purification process and regeneration process are alternately switched between two adsorption columns, can suppress fluctuations in oxygen concentration in purified air that occur before and after switching. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing an air purification device according to one embodiment of the present invention; [Diagram 2] 2 is a flowchart showing an example of a regeneration process executed in the adsorption column shown in FIG. [Diagram 3] FIG. 3 is an explanatory diagram showing the air purification device in a state in which the pre-pressure equalization step shown in FIG. 2 is being performed. [Figure 4]FIG. 3 is an explanatory diagram showing the air purification device in a state in which the pressure equalization step shown in FIG. 2 has been performed. [Diagram 5] FIG. 3 is an explanatory diagram showing the air purification apparatus in a state in which the flow purge process as the post-pressure equalization process shown in FIG. 2 is being performed. [Figure 6] 3 is a diagram showing a modified method for performing the pressure equalization step shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an air purification device and an air purification method according to the present invention will be described by way of example with reference to the drawings. In each drawing, the same components are designated by the same reference numerals.

[0019] <Air Purification Device 1> Fig. 1 is a system diagram showing the configuration of an air purification apparatus 1 as one embodiment of the air purification apparatus according to the present invention. As shown in Fig. 1, the air purification apparatus 1 of this embodiment includes two adsorption columns 2A and 2B, a feed air introduction path L1, a purified air discharge path L2, a regeneration gas supply path L3, a heating means 3, an exhaust path L4, and a flow rate adjustment unit 4. The air purification apparatus 1 of this embodiment is an apparatus for purifying feed air by removing impurities such as water and carbon dioxide from the feed air by a temperature swing adsorption (TSA) method.

[0020] The two adsorption columns 2A and 2B are cylindrical adsorption vessels that are heat-resistant and pressure-resistant. The shape of the vessels is not particularly limited.

[0021] The two adsorption columns 2A, 2B are each filled with an adsorbent capable of adsorbing water and carbon dioxide as impurities in the feed air. The adsorbent capable of adsorbing water may be, for example, activated alumina. The adsorbent capable of adsorbing carbon dioxide may be, for example, synthetic zeolite. The two adsorption columns 2A, 2B may each be filled with an adsorbent capable of adsorbing impurities other than water and carbon dioxide in the feed air.

[0022] 1, branched feed air inlet paths L1A and L1B branching off from feed air inlet path L1 are connected to one end of adsorption column 2A and one end of adsorption column 2B, respectively. This allows raw air before purification to be supplied to adsorption columns 2A and 2B via feed air inlet path L1.

[0023] Furthermore, branched purified air outlet paths L2A, L2B branching off from purified air outlet path L2 are connected to the other ends of adsorption columns 2A, 2B, respectively. This allows purified air, from which impurities such as water and carbon dioxide have been removed in adsorption columns 2A, 2B, to be taken out via purified air outlet path L2 and supplied to the outside from adsorption columns 2A, 2B.

[0024] The branched raw air introduction paths L1A and L1B are provided with on-off valves V1A and V1B, respectively. The branched purified air discharge paths L2A and L2B are provided with on-off valves V2A and V2B, respectively. By controlling the open / close states of the on-off valves V1A, V1B, V2A, and V2B, raw air can be supplied to only one of the adsorption columns 2A and 2B. For example, when raw air is to be supplied only to the adsorption column 2A, the on-off valves V1A and V2A are opened, and the on-off valves V1B and V2B are closed. For example, when raw air is to be supplied only to the adsorption column 2B, the on-off valves V1A and V2A are closed, and the on-off valves V1B and V2B are opened.

[0025] One end of the regeneration gas supply line L3 is connected to the purified air outlet line L2, and the other end is connected to the branch regeneration gas supply lines L3A and L3B. The branch regeneration gas supply line L3A is connected on the branch purified air outlet line L2A between the other end of the adsorption column 2A and the on-off valve V2A. The branch regeneration gas supply line L3B is connected on the branch purified air outlet line L2B between the other end of the adsorption column 2B and the on-off valve V2B.

[0026] A portion of the purified air is supplied as regeneration gas from the purified air discharge path L2 to the regeneration gas supply path L3, and the regeneration gas can be supplied to the adsorption columns 2A and 2B via the regeneration gas supply path L3.

[0027] The branched regeneration gas supply paths L3A and L3B are provided with on-off valves V3A and V3B, respectively. By controlling the on-off states of the on-off valves V3A and V3B, regeneration gas can be supplied to only one of the adsorption columns 2A and 2B. For example, when regeneration gas is to be supplied only to the adsorption column 2B, the on-off valve V3B is opened and the on-off valve V3A is closed. Also, when regeneration gas is to be supplied only to the adsorption column 2A, the on-off valve V3B is closed and the on-off valve V3A is opened.

[0028] The heating means 3 is provided on the regeneration gas supply path L3. The heating means 3 heats the supplied regeneration gas to warm it. Therefore, the temperature of the regeneration gas supplied from the regeneration gas supply path L3 to the adsorption columns 2A and 2B is high. In this way, by supplying the heated regeneration gas to the adsorption columns 2A and 2B, the adsorbent is heated by the regeneration gas, and the adsorbent can be thermally regenerated.

[0029] A branch exhaust passage L4A is connected to the branch feed air introduction passage L1A between one end of the adsorption column 2A and the on-off valve V1A, and a branch exhaust passage L4B is connected to the branch feed air introduction passage L1B between one end of the adsorption column 2B and the on-off valve V1B.

[0030] The branch exhaust path L4A and the branch exhaust path L4B are connected midway to form the exhaust path L4. The exhaust path L4 allows the exhaust gas generated in the adsorption columns 2A and 2B to be exhausted to the outside. The "exhaust gas" referred to here means a gas in which impurities desorbed from the adsorbent are mixed with the regeneration gas.

[0031] The branch exhaust paths L4A and L4B are provided with on-off valves V4A and V4B, respectively. By controlling the open / close states of the on-off valves V4A and V4B, the exhaust gases generated in the adsorption columns 2A and 2B can be exhausted to the outside. For example, when exhaust gas generated in the adsorption column 2B is exhausted to the outside, the on-off valve V4B is opened and the on-off valve V4A is closed. Also, for example, when exhaust gas generated in the adsorption column 2A is exhausted to the outside, the on-off valve V4B is closed and the on-off valve V4A is opened.

[0032] Furthermore, by controlling the open / close states of the above-mentioned on-off valves V1A, V1B, V2A, V2B, V3A, V3B, V4A, and V4B, an air purification process for removing impurities from the raw air can be performed in one of the two adsorption columns 2A and 2B, while impurities adsorbed in the adsorbent can be supplied to the exhaust path L4 from the other adsorption column to perform a regeneration process for regenerating the adsorption capacity of the adsorbent. For example, when the air purification process is performed in the adsorption column 2A and the regeneration process is performed in the adsorption column 2B, the on-off valves V1A, V2A, V3B, and V4B are opened, and the on-off valves V1B, V2B, V3A, and V4A are closed. Also, for example, when the air purification process is performed in the adsorption column 2B and the regeneration process is performed in the adsorption column 2A, the on-off valves V1A, V2A, V3B, and V4B are closed, and the on-off valves V1B, V2B, V3A, and V4A are opened. In this manner, the air purification device 1 is provided with two adsorption columns 2A, 2B that are capable of alternately carrying out air purification processing and regeneration processing.

[0033] Further, the exhaust path L4 is provided with a flow rate adjustment unit 4 capable of adjusting the flow rate. More specifically, the exhaust path L4 of this embodiment includes an exhaust gas path L41 and a flow purge gas path L42. The exhaust gas path L41 is a path capable of exhausting exhaust gas from one of the adsorption tubes in which regeneration processing is being performed. The flow purge gas path L42 is a path capable of exhausting flow purge gas from one of the adsorption tubes in which regeneration processing is being performed. The exhaust gas path L41 is provided with an opening and closing valve V41. Furthermore, the flow purge gas path L42 is provided with an opening and closing valve V42 whose flow rate in an open state is smaller than that of the opening and closing valve V41. This allows the flow rate in the flow purge gas path L42 in which the opening and closing valve V42 is open to be smaller than the flow rate in the exhaust gas path L41 in which the opening and closing valve V41 is open. The flow rate adjustment unit 4 of this embodiment is configured to include the above-mentioned opening and closing valve V41 and opening and closing valve V42. Hereinafter, for ease of explanation, in order to distinguish between the on-off valve V41 and the on-off valve V42, the on-off valve V41 will be referred to as the "first on-off valve V41" and the on-off valve V42 will be referred to as the "second on-off valve V42." As will be described in detail later, one of the adsorption cylinders undergoing regeneration treatment is made to be in a pressure-equal state with the other adsorption cylinder undergoing air purification treatment by operating the flow rate adjustment unit 4. More specifically, in this embodiment, one of the adsorption cylinders undergoing regeneration treatment is made to be in a pressure-equal state with the other adsorption cylinder undergoing air purification treatment by operating the open / close states of the first on-off valve V41 and the second on-off valve V42.

[0034] The configurations of the above-mentioned opening and closing valves V1A, V1B, V2A, V2B, V3A, V3B, V4A, and V4B, the first opening and closing valve V41, and the second opening and closing valve V42 are not particularly limited. These opening and closing valves may be configured, for example, by air-operated valves, solenoid valves, needle valves, and the like. In this embodiment, as an example, the opening and closing valves V1A, V1B, V2A, V2B, V3A, V3B, V4A, and V4B, and the first opening and closing valve V41 are configured by air-operated valves. Also, in this embodiment, as an example, the second opening and closing valve V42 is configured by a needle valve.

[0035] <Air purification method> Next, an air purification method using the above-mentioned air purification device 1 will be described as one embodiment of the air purification method according to the present invention. In the air purification method of this embodiment, adsorption columns 2A and 2B are connected in parallel, and an air purification process for purifying raw air is performed in one adsorption column, and a regeneration process for regenerating the adsorbent is performed in the other adsorption column. By alternately switching between the above-mentioned air purification process and regeneration process between the two adsorption columns 2A and 2B, air can be continuously purified as a whole. In the present embodiment, for convenience of explanation, a method in which the air purification process is performed in the adsorption column 2A and the regeneration process is performed in the adsorption column 2B will be exemplified below, but the same applies if it is performed vice versa.

[0036] (Air purification process) First, the on-off valves V1A, V2A, V3B, and V4B are opened, and the on-off valves V1B, V2B, V3A, and V4A are closed. As a result, the raw air supplied from the raw air inlet path L1 is supplied to the adsorption column 2A via the branched raw air inlet path L1A. Then, the adsorbent in the adsorption column 2A removes impurities such as water and carbon dioxide from the raw air at room temperature to generate purified air. The impurities such as water and carbon dioxide are adsorbed by the adsorbent. Then, the purified air is supplied to the outside via the branched purified air outlet path L2A and the purified air outlet path L2.

[0037] (Recycling) On the other hand, while the purified air is being supplied to the outside from the purified air discharge path L2, a part of the purified air is supplied as regeneration gas via the regeneration gas supply path L3 to the heating means 3. The heating means 3 heats the supplied regeneration gas and supplies the heated regeneration gas to the adsorption column 2B via the regeneration gas supply path L3 and the branch regeneration gas supply path L3B.

[0038] Next, in adsorption column 2B, the heated regeneration gas heats the adsorbent in adsorption column 2B to, for example, 100 to 300°C, thereby desorbing impurities such as water and carbon dioxide from the adsorbent and regenerating the adsorption capacity of the adsorbent. The desorbed impurities mix with the regeneration gas and become exhaust gas, which is exhausted to the outside via branch exhaust path L4B and exhaust path L4.

[0039] By the above process, air purification process can be performed in adsorption column 2A, and regeneration process can be performed in adsorption column 2B.

[0040] Next, the on-off valves V1B, V2B, V3A, and V4A are opened, and the on-off valves V1A, V2A, V3B, and V4B are closed. This allows the adsorption column 2A to perform a regeneration process while the adsorption column 2B performs an air purification process. By alternately switching between these, the air can be purified continuously as a whole.

[0041] (Details of the playback process) Next, the regeneration process executed in the adsorption column 2B will be described in detail with reference to Figures 2 to 5. Figure 2 is a flow chart showing an example of the regeneration process executed in the adsorption column 2B.

[0042] While the air purification process is being performed in adsorption column 2A, the regeneration process shown in Fig. 2 is being performed in adsorption column 2B. As shown in Fig. 2, the regeneration process in adsorption column 2B includes a pre-pressure equalization step S1, a pressure equalization step S2, and a flow purging step S3 as a post-pressure equalization step. Fig. 3 is an explanatory diagram showing a state in which the pre-pressure equalization step S1 is being performed. Fig. 4 is an explanatory diagram showing a state in which the pressure equalization step S2 has been performed from the state shown in Fig. 3. Fig. 5 is an explanatory diagram showing a state in which the flow purging step S3 as a post-pressure equalization step is being performed from the state shown in Fig. 4.

[0043] As shown in Fig. 2, the pre-pressure equalization step S1 includes a heating regeneration step S1a and a cooling step S1b. Also, as shown in Fig. 2, the pre-pressure equalization step S1 may further include a batch purge step S1c in addition to the heating regeneration step S1a and the cooling step S1b.

[0044] As described above, the thermal regeneration step S1a is performed by heating the adsorbent by supplying the heated regeneration gas to the adsorption column 2B. The impurities adsorbed to the adsorbent at room temperature in the air purification process are desorbed from the adsorbent by heating the adsorbent in the thermal regeneration step S1a. This allows the adsorption capacity of the adsorbent to be regenerated. As shown in FIG. 3, the impurities desorbed from the adsorbent are mixed with the regeneration gas and become exhaust gas, which is exhausted from the exhaust path L4. In this thermal regeneration step S1a, the exhaust gas is exhausted through the exhaust gas path L41 of the exhaust path L4. That is, in the thermal regeneration step S1a in the pre-pressure equalization step S1, the first opening and closing valve V41 provided in the exhaust gas path L41 is opened, and the second opening and closing valve V42 provided in the flow purge gas path L42 is closed. As the regeneration gas, a part of the purified air purified in the adsorption column 2A may be used as the regeneration gas as in this embodiment, but another gas may be used as the regeneration gas.

[0045] The cooling step S1b is performed, for example, by flowing a regeneration gas at room temperature into the adsorption column 2B as a cooling gas. This allows the adsorbent heated in the thermal regeneration step S1a and the adsorption column 2B filled with the adsorbent to be cooled for the air purification process performed at room temperature after the regeneration process. As shown in FIG. 3, the cooling gas used in the cooling step S1b is also exhausted from the exhaust path L4. In this cooling step S1b, the cooling gas is exhausted through the exhaust gas path L41 of the exhaust path L4, similar to the above-mentioned thermal regeneration step S1a. That is, in the cooling step S1b in the pre-pressure equalization step S1, the first opening and closing valve V41 provided in the exhaust gas path L41 is opened, and the second opening and closing valve V42 provided in the flow purge gas path L42 is closed. Note that, as in this embodiment, the regeneration gas may be used as the cooling gas, but another gas may be used as the cooling gas.

[0046] The batch purge step S1c is performed by repeatedly varying the internal pressure of the adsorption column 2B between a low pressure state and a high pressure state. The internal pressure of the adsorption column 2B may be varied between atmospheric pressure (0.1 MPa) and 0.7 MPa, for example. By performing the batch purge step S1c, it is possible to promote the removal of impurities remaining in the adsorption column 2B. The batch purge step S1c may be performed, for example, by manipulating the opening and closing states of the opening and closing valves V4A and V4B. As shown in FIG. 3, the batch purge gas used in the batch purge step S1c is also exhausted from the exhaust path L4. In this batch purge step S1c, the batch purge gas is exhausted through the exhaust gas path L41 of the exhaust path L4, similar to the above-mentioned thermal regeneration step S1a and cooling step S1b. That is, in the batch purge step S1c in the pre-pressure equalization step S1, the first on-off valve V41 provided in the exhaust gas path L41 is opened, and the second on-off valve V42 provided in the flow purge gas path L42 is closed. As the batch purge gas supplied to the adsorption column 2B in the batch purge step S1c, for example, the regeneration gas at room temperature may be used as in the cooling step S1b described above, but another gas may also be used as the batch purge gas.

[0047] As described above, in the pre-pressure equalization step S1 of this embodiment, the heating regeneration step S1a, the cooling step S1b, and the batch purge step S1c are performed. Also, as described above, in the pre-pressure equalization step S1, the gases (regeneration gas, cooling gas, and batch purge gas) used in each of the heating regeneration step S1a, the cooling step S1b, and the batch purge step S1c are exhausted through the exhaust gas path L41 of the exhaust path L4 (see FIG. 3).

[0048] Next, the pressure equalization step S2 is performed. In the pressure equalization step S2, purified air purified by the adsorption column 2A is supplied to the adsorption column 2B after the pre-pressure equalization step S1 is performed, and the pressure is equalized with the adsorption column 2A in which the air purification process is being performed. More specifically, as shown in FIG. 4, the pressure equalization step S2 of this embodiment is performed by manipulating the opening and closing states of the first opening and closing valve V41 and the second opening and closing valve V42. That is, the pressure equalization step S2 is performed by closing the first opening and closing valve V41 provided in the exhaust gas path L41 and opening the second opening and closing valve V42 provided in the flow purge gas path L42. As described above, the flow rate in the flow purge gas path L42 when the second opening and closing valve V42 is open is smaller than the flow rate in the exhaust gas path L41 when the first opening and closing valve V41 is open. Therefore, even if the second on-off valve V42 is open in the flow purge gas path L42 connected to the adsorption column 2B, the adsorption column 2B is pressurized by being connected to the adsorption column 2A in which the air purification process is being performed, and is equalized in pressure with the adsorption column 2A.

[0049] In this embodiment, the exhaust path L4 is provided with the exhaust gas path L41 and the flow purge gas path L42, and the exhaust gas path L41 is provided with the first opening / closing valve V41 and the flow purge gas path L42 is provided with the second opening / closing valve V42, but the configuration is not limited to this. In other words, the configuration is not particularly limited as long as the flow rate adjustment unit 4 can adjust the flow rate of the exhaust path L4.

[0050] For example, the exhaust gas path L41 and the flow purge gas path L42 in this embodiment are designed to have substantially equal cross-sectional areas and have substantially equal flow rates. Therefore, in this embodiment, the flow rates in the exhaust gas path L41 and the flow purge gas path L42 are adjusted by operating the opening and closing states of the first opening and closing valve V41 and the second opening and closing valve V42 as described above, thereby realizing pressure equalization of the adsorption columns 2A and 2B. However, the pressure equalization of the adsorption columns 2A and 2B may be realized by other means. For example, the flow purge gas path L42 may be provided with a narrow diameter portion or the like, so that the flow rates of the exhaust gas path L41 and the flow purge gas path L42 are made different from each other, and a switching valve capable of switching between the exhaust gas path L41 and the flow purge gas path L42 may be operated to realize the above-mentioned pressure equalization of the adsorption columns 2A and 2B.

[0051] In addition, the exhaust gas path L41 and the flow purge gas path L42 of this embodiment are different only in some of the branch paths arranged in parallel, and the other parts are common, but are not limited to this configuration. The exhaust gas path L41 and the flow purge gas path L42 may be configured as completely separate paths. However, by configuring the exhaust gas path L41 and the flow purge gas path L42 of this embodiment such that only some of the branch paths are different, and providing the first opening and closing valve V41 and the second opening and closing valve V42 in this branch path, the configuration of the exhaust path L4 can be simplified and the exhaust path L4 can be prevented from becoming complicated.

[0052] Next, a flow purge step S3 is performed as a post-pressure equalization step. In the flow purge step S3, a flow purge is performed in which a flow purge gas is flowed into the adsorption column 2B while maintaining the two adsorption columns 2A and 2B in an equal pressure state. As shown in Fig. 5, the flow purge gas is exhausted through a flow purge gas path L42 of the exhaust path L4. Purified air purified by the adsorption column 2A is used as the flow purge gas.

[0053] In the above-mentioned pressure equalization step S2, when the adsorption column 2B is filled and equalized with the internal pressure of the adsorption column 2A, adsorption of oxygen and nitrogen to the adsorbent or desorption from the adsorbent may occur in the adsorption column 2B. Therefore, if the regeneration process is switched to the air purification process immediately after the pressure equalization step S2, the oxygen concentration of the purified air purified from the adsorption column 2B immediately after the switching may differ from the oxygen concentration of the purified air purified by the adsorption column 2A until then. In response to this, by performing the flow purge step S3 as a post-pressure equalization step after the pressure equalization step S2, the purified air purified by the adsorption column 2A that was contained in the adsorption column 2B when the pressure equalization step S2 was performed can be exhausted through the flow purge gas path L42 before switching to the air purification process. At the same time, the purified air purified by the adsorption column 2A can be supplied to the adsorption column 2B while maintaining the two adsorption columns 2A and 2B in an equalized state. This makes it possible to reduce the fluctuation in oxygen concentration before and after the switching caused by the above-mentioned pressure equalization step S2.

[0054] The flow purge performed in the flow purge step S3 may be performed, for example, so that the variation in oxygen concentration before and after the above-mentioned switching is within ±1%. To achieve this, the flow purge is preferably performed, for example, at a space velocity of 5 to 10 times / hour with respect to the volume of the adsorption column 2B. The time for performing the flow purge may be, for example, 10 to 120 minutes.

[0055] Immediately after the flow purge step S3 is performed, the adsorption column 2B is switched to perform the air purification process. That is, in the air purification device 1, one of the two adsorption columns 2A, 2B, which is undergoing regeneration processing, is switched to perform the air purification process after a flow purge is performed in a pressure equalization state with the other adsorption column 2A, which is undergoing air purification processing. In this manner, the regeneration processing of the adsorption column 2B is completed, and the regeneration processing of the adsorption column 2A is started. The regeneration processing of the adsorption column 2A is similar to the regeneration processing of the adsorption column 2B described above.

[0056] The flow purge step S3 is preferably performed immediately before switching from the regeneration process to the air purification process. Therefore, the adsorption column 2B may be in a standby state for a certain period of time after the above-mentioned pressure equalization step S2 is completed. If this standby state continues for a long period of time, for example, impurities may be desorbed from the inner surface of the adsorption column 2B. Therefore, for example, if the standby state time is longer than a predetermined period of time, the batch purge step S1c of the pre-pressure equalization step S1 and the pressure equalization step S2 may be performed again before performing the above-mentioned flow purge step S3.

[0057] Furthermore, adsorption column 2B is switched to perform air purification processing immediately after the flow purge step S3 is performed, and both adsorption columns 2A and 2B may perform air purification processing immediately after this switching. In other words, a combined process in which air purification processing is performed simultaneously in the two adsorption columns 2A and 2B may be performed for a predetermined time. In this way, continuous purification of air can be performed more reliably. The time for performing the combined process is not particularly limited, and may be, for example, several tens of seconds to several tens of minutes. After this combined process, adsorption column 2A is switched from air purification processing to regeneration processing.

[0058] As described above, in the air purification device 1 of this embodiment, in the regeneration process of one adsorption column 2B, before the one adsorption column 2B and the other adsorption column 2A are equalized in pressure (see FIG. 3), exhaust gas is exhausted from the one adsorption column 2B through exhaust path L4 (exhaust gas path L41 of exhaust path L4 in this embodiment) (see FIG. 3). Then, after the one adsorption column 2B and the other adsorption column 2A are equalized in pressure (see FIG. 4), flow purge is performed in which flow purge gas is exhausted from the one adsorption column 2B through exhaust path L4 (flow purge gas path L42 of exhaust path L4 in this embodiment) (see FIG. 5).

[0059] In particular, in the air purification device 1 of this embodiment, a flow rate adjustment unit 4 capable of adjusting the flow rate is provided in the exhaust path L4, and one adsorption column 2B is made equal in pressure to the other adsorption column 2A by operating the flow rate adjustment unit 4. More specifically, in the air purification device 1 of this embodiment, the exhaust path L4 includes an exhaust gas path L41 and a flow purge gas path L42. A first opening / closing valve V41 is provided in the exhaust gas path L41, and a second opening / closing valve V42 is provided in the flow purge gas path L42, as the flow rate adjustment unit 4 capable of adjusting the flow rate of the exhaust path L4. Therefore, in this embodiment, one adsorption column 2B is made equal in pressure to the other adsorption column 2A by operating the opening / closing states of the first opening / closing valve V41 and the second opening / closing valve V42 (see FIG. 4).

[0060] The air purification device and air purification method according to the present invention are not limited to the specific configurations and steps shown in the above-mentioned embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0061] In the above-described embodiment, the flow rates in the exhaust gas path L41 and the flow purge gas path L42 are adjusted by controlling the open / close states of the first on-off valve V41 and the second on-off valve V42, thereby realizing pressure equalization of the adsorption columns 2A and 2B. However, the pressure equalization of the adsorption columns 2A and 2B is not limited to the above-described method. In the pressure equalization step S2, for example, as shown in FIG. 6, the on-off valve V4B may be switched from an open state to a closed state to fill the adsorption column 2B and equalize the pressure with the adsorption column 2A. In this way, the adsorption columns 2A and 2B can be more quickly brought into a pressure equalization state. Then, the flow purge step S3 shown in FIG. 5 is performed after that. Note that in the example shown in FIG. 6, the on-off valve V4B is closed to equalize the pressure of the adsorption columns 2A and 2B, so that in the pressure equalization step S2, it is not essential to switch the first on-off valve V41 from an open state to a closed state and to switch the second on-off valve V42 from a closed state to an open state. In other words, the above-described opening and closing operations of the first opening and closing valve V41 and the second opening and closing valve V42 may be performed when the flow purge step S3 is performed after the pressure equalization step S2 is completed. [Industrial Applicability]

[0062] The present invention relates to an air purification device and an air purification method. [Explanation of symbols]

[0063] 1: Air purifier 2A, 2B: Adsorption cylinder 3: Heating means 4:Flow rate adjustment part L1: Feed air introduction path L1A, L1B: Branch feed air introduction route L2: Purified air outlet path L2A, L2B: Branched purified air outlet route L3: Regenerated gas supply route L3A, L3B: Branched regeneration gas supply route L4: Exhaust route L4A, L4B: Branch exhaust route L41: Exhaust gas route L42: Flow purge gas route V1A, V1B, V2A, V2B, V3A, V3B, V4A, V4B: Opening and closing valves V41: First opening and closing valve V42: Second opening and closing valve

Claims

1. 1. An air purification apparatus for purifying a feed air by removing impurities from the feed air by a temperature swing adsorption method, comprising: two adsorption columns filled with an adsorbent capable of adsorbing the impurities, and capable of alternately performing an air purification process for purifying the raw air using the adsorbent and a regeneration process for regenerating the adsorption capacity of the adsorbent; a regeneration gas supply path capable of supplying a regeneration gas to the two adsorption columns in the regeneration treatment; an exhaust path capable of exhausting exhaust gas in a state in which the impurities desorbed from the adsorbent in the regeneration process are mixed with the regeneration gas from the two adsorption columns; two branch exhaust paths connecting the two adsorption cylinders and the exhaust path, The exhaust path is an exhaust gas path capable of discharging the exhaust gas from one of the two adsorption columns in which the regeneration process is being performed; a flow purge gas passage capable of discharging the flow purge gas from the one of the adsorption columns when the flow purge is performed, the one adsorption column is made to be in a pressure equalizing state with the other adsorption column of the two adsorption columns in which the air purification process is being performed, and then a flow purge is performed thereon; and after the flow purge is performed, the one adsorption column is switched to the execution of the air purification process; An air purification apparatus in which one of the adsorption tubes is pressurized with the regeneration gas and equalized in pressure with the other adsorption tube by switching an opening / closing valve provided in one of the two branch exhaust paths that connects the one of the adsorption tubes to the exhaust path from an open state to a closed state.

2. An air purification apparatus as described in claim 1, wherein in the regeneration process, before the one adsorption tube is brought into a state of equal pressure with the other adsorption tube, the exhaust gas is exhausted from the one adsorption tube through the exhaust gas path of the exhaust route, and after the one adsorption tube is brought into a state of equal pressure with the other adsorption tube, the flow purge is performed in which flow purge gas is exhausted from the one adsorption tube through the flow purge gas path of the exhaust route.

3. A first opening and closing valve is provided in the exhaust gas path, a second opening / closing valve having a flow rate in an open state smaller than that of the first opening / closing valve is provided in the flow purge gas path; 3. The air purification apparatus according to claim 1, wherein the flow purge is performed while the first opening / closing valve is closed and the second opening / closing valve is open, and while the two adsorption columns are maintained in an equal pressure state.

4. A method for purifying raw air by removing impurities from the raw air using an air purification apparatus by a temperature swing adsorption method, comprising: The air purification device comprises: two adsorption columns filled with an adsorbent capable of adsorbing the impurities, and capable of alternately performing an air purification process for purifying the raw air using the adsorbent and a regeneration process for regenerating the adsorption capacity of the adsorbent; a regeneration gas supply path capable of supplying a regeneration gas to the two adsorption columns in the regeneration treatment; an exhaust path capable of exhausting exhaust gas in a state in which the impurities desorbed from the adsorbent in the regeneration process are mixed with the regeneration gas from the two adsorption columns; two branch exhaust paths connecting the two adsorption cylinders and the exhaust path, The exhaust path is an exhaust gas path capable of discharging the exhaust gas from one of the two adsorption columns in which the regeneration process is being performed; a flow purge gas passage capable of discharging the flow purge gas from the one of the adsorption columns when the flow purge is performed, A continuous purification process in which the air purification process and the regeneration process are alternately performed by the two adsorption columns, In the continuous purification step, one of the adsorption columns is subjected to a flow purge after being brought into a pressure equalizing state with the other of the two adsorption columns in which the air purification process is being performed, and after the flow purge is performed, the adsorption column is switched to perform the air purification process; In this air purification method, an opening / closing valve provided in one of the two branch exhaust paths connecting the one of the adsorption tubes to the exhaust path is switched from an open state to a closed state, so that the one of the adsorption tubes is pressurized with the regeneration gas and is equalized in pressure with the other adsorption tube.

5. An air purification method as described in claim 4, wherein in the regeneration process, before the one adsorption tube is brought into a state of equal pressure with the other adsorption tube, the exhaust gas is exhausted from the one adsorption tube through the exhaust gas path of the exhaust route, and after the one adsorption tube is brought into a state of equal pressure with the other adsorption tube, the flow purge is performed in which a flow purge gas is exhausted from the one adsorption tube through the flow purge gas path of the exhaust route.

6. A first opening and closing valve is provided in the exhaust gas path, a second opening / closing valve having a flow rate in an open state smaller than that of the first opening / closing valve is provided in the flow purge gas path; 6. The air purification method according to claim 4, wherein the flow purge is performed while the first opening / closing valve is closed and the second opening / closing valve is open, thereby maintaining the two adsorption columns in an equal pressure state.

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