Gas concentration device

Abstract

To make it possible to recover carbon dioxide at a higher concentration than when recovering carbon dioxide from a gas by a one-stage gas concentration process.SOLUTION: A gas concentration device 1 comprises: a gas intake unit 10 that takes in a gas; a first concentration unit 2 that generates from the intake gas a first concentrated gas in which the concentration of carbon dioxide is increased; a second concentration unit 5 that generates from the first concentrated gas a second concentrated gas in which the concentration of carbon dioxide is further increased; and a gas exhaust unit 70 that exhausts the second concentrated gas to the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for concentrating gases from the atmosphere. [Background technology]

[0002] Conventionally, devices for concentrating gas components in a gas have been known.

[0003] For example, Patent Document 1 describes a gas concentration device that recovers highly concentrated carbon dioxide from a raw material gas (gas) containing carbon dioxide through a one-stage gas concentration process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-127000 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 has a limit to the concentration of gas that can be concentrated depending on the gas concentration, and it has not been possible to directly recover higher-concentration carbon dioxide from the atmosphere at a very low concentration.

[0006] In view of the above problems, the present invention aims to provide a gas concentration device that can recover carbon dioxide at a higher concentration compared to recovering carbon dioxide from a gas through a single-stage gas concentration process. [Means for solving the problem]

[0007] To solve the above problems, according to a first aspect of the present invention, there is provided the following gas concentration device: This gas concentration device includes a gas intake unit that takes in gas, a first concentration unit that produces a first concentrated gas from the taken in gas by increasing the concentration of carbon dioxide, a second concentration unit that produces a second concentrated gas from the first concentrated gas by further increasing the concentration of carbon dioxide, and a gas exhaust unit that exhausts the second concentrated gas to the outside.

[0008] In addition, in a gas concentration apparatus according to a second aspect of the present invention, the first concentration section has a first adsorption section that adsorbs and desorbs carbon dioxide from the gas to produce the first concentrated gas, and the second concentration section has a second adsorption section that adsorbs and desorbs carbon dioxide from the first concentrated gas to produce the second concentrated gas, and further comprises a pump configured to adjust the pressure within the first concentration section and the pressure within the second concentration section, and a control device that controls the pump and adjusts the pressure within the first concentration section and the pressure within the second concentration section.

[0009] In addition, in a gas concentration device according to a third aspect of the present invention, the first concentration section has a first switching section configured to be able to switch the supply destination of the gas, the first adsorption section has a first adsorption tank and a second adsorption tank, the second concentration section has a second switching section configured to be able to switch the supply destination of the first concentrated gas, and the second adsorption section has a third adsorption tank and a fourth adsorption tank, and the control device controls the first switching section to switch the supply destination of the gas and controls the second switching section to switch the supply destination of the first concentrated gas.

[0010] In the gas concentrating apparatus according to the fourth aspect of the present invention, the volume of the gas in the first concentrating section is different from the volume of the gas in the second concentrating section.

[0011] In addition, in a gas concentrating apparatus according to a fifth aspect of the present invention, the volume of the third adsorption tank or the volume of the fourth adsorption tank is smaller than the volume of the first adsorption tank or the volume of the second adsorption tank.

[0012] In addition, in a gas concentration apparatus according to a sixth aspect of the present invention, the volume of the third adsorption tank or the volume of the fourth adsorption tank is less than three-quarters and more than one-half of the volume of the first adsorption tank or the second adsorption tank.

[0013] In addition, in a gas concentration apparatus according to a seventh aspect of the present invention, the first concentration section has a first buffer tank that reduces pressure fluctuations within the first concentration section, and the second concentration section has a second buffer tank that reduces pressure fluctuations within the second concentration section, and the volume of the second buffer tank is smaller than the volume of the first buffer tank.

[0014] Moreover, the gas concentrating apparatus according to an eighth aspect of the present invention further comprises a throttle valve configured to be able to adjust the flow rate of the first concentrated gas.

[0015] In addition, in a gas concentration device according to a ninth aspect of the present invention, the first concentration section has a first exhaust valve that exhausts the first concentrated gas, the second concentration section has a second exhaust valve that exhausts the second concentrated gas, and the control device controls the first switching section and the first exhaust valve in conjunction with each other to adjust the timing of the exhaust of the gas and the exhaust of the first concentrated gas, and controls the second switching section and the second exhaust valve in conjunction with each other to adjust the timing of the exhaust of the first concentrated gas and the exhaust of the second concentrated gas.

[0016] In addition, in a gas concentration device according to a tenth aspect of the present invention, the first concentration section has a first filter that filters the first concentrated gas, and the second concentration section has a second filter that filters the second concentrated gas. [Effects of the Invention]

[0017] The gas concentrator according to the present invention makes it possible to recover carbon dioxide at a higher concentration than when carbon dioxide is recovered from a gas through a single-stage gas concentration process. [Brief explanation of the drawings]

[0018] [Figure 1]1 is a diagram illustrating an example of the overall configuration of a gas concentrating device according to an embodiment of the present invention. [Figure 2] 2 is a timing chart showing an example of the flow of processing in the first concentrating section of the gas concentrating device of FIG. 1. [Figure 3] FIG. 10 is a diagram showing the gas flow in the first enrichment section at time T11. [Figure 4] FIG. 10 is a diagram showing the gas flow in the first enrichment section at time T14. [Figure 5] 2 is a timing chart showing an example of the flow of processing in the second concentrating section of the gas concentrating device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0020] <Embodiment> First, a gas concentrating device 1 according to an embodiment of the present invention will be described.

[0021] <Overall structure> FIG. 1 is a diagram schematically illustrating an example of the overall configuration of a gas concentrating device 1 according to an embodiment of the present invention.

[0022] 1, the gas concentrator 1 includes a gas intake section 10, a pump 9, a water removal tank 12, a first concentrator 2, a second concentrator 5, and a control device 8. Note that the specific configuration of the gas concentrator 1 is not limited to that shown in FIG.

[0023] The gas concentrator 1 takes in gas from outside the gas concentrator 1 and generates a second concentrated gas with an increased concentration of carbon dioxide. Note that the gas components whose concentrations can be increased by the gas concentrator 1 are not limited to carbon dioxide, and may include nitrogen, oxygen, hydrogen, carbon monoxide, or the like.

[0024] First, we will explain the gas intake unit 10. The gas intake unit 10 takes in gas from outside the gas concentrator 1 into the gas concentrator 1. Specifically, the gas intake unit 10 supplies gas from outside the gas concentrator 1 to the air pump 11. The gas taken in may be the atmosphere or a separately prepared raw material gas.

[0025] Next, the pump 9 will be described. The pump 9 is configured to be able to adjust the pressure in the first concentrating section 2 and the pressure in the second concentrating section 5. Specifically, the gas concentrator 1 includes, as the pump 9, an air pump 11, a first decompression pump 25, a first boost pump 27, a second decompression pump 55, and a second boost pump 57. The air pump 11 supplies gas sucked in from the gas intake section 10 to the water removal tank 12.

[0026] Next, the water removal tank 12 will be described. The water removal tank 12 removes moisture from the gas sucked from the air pump 11, thereby reducing the moisture content in the gas. The gas with reduced moisture content is supplied to the first inlet portion 20.

[0027] Next, the first concentrating section 2 will be described. The first concentrating section 2 includes a first inlet section 20, a first switching section 21, a first adsorption section 22, a first pressure sensor 29, a first exhaust section 30, a first filter 31, a first check valve 33, a first throttle valve 35, a second throttle valve 37, a first exhaust valve 39, a first buffer tank 41, and a first outlet section 40. The first concentrating section 2 generates a first concentrated gas with an increased concentration of carbon dioxide from gas taken in from outside the gas concentrating apparatus 1.

[0028] The first inlet section 20 is an intake port that takes in gas from outside the first condensing section 2 into the first condensing section 2. Specifically, gas is supplied from the water removal tank 12 to the first switching section 21.

[0029] The first switching unit 21 is configured to be able to switch the supply destination of the gas supplied from the first inlet unit 20. The first switching unit 21 includes a first solenoid valve 21A, a first solenoid valve 21B, a first solenoid valve 21C, and a first solenoid valve 21D. The gas flow path is controlled by switching each solenoid valve between an open state (OPEN) and a closed state (CLOSE), thereby switching the supply destination of the gas. Each solenoid valve prevents backflow from the supply side to the intake side, and the side marked "IN" is the intake side. Specifically, the first solenoid valve 21A is a solenoid valve that controls the supply of gas from the water removal tank 12 to the first adsorption tank 23. The first solenoid valve 21B is a solenoid valve that controls the supply of gas from the water removal tank 12 to the second adsorption tank 24. The first solenoid valve 21C is a solenoid valve that controls the supply of gas from the first adsorption tank 23 to the first filter 31. The first electromagnetic valve 21D is a electromagnetic valve that controls the supply of gas from the second adsorption tank 24 to the first filter 31.

[0030] The first adsorption unit 22 adsorbs and desorbs carbon dioxide from gas taken in from outside the gas concentrator 1 to generate a first concentrated gas. The first adsorption unit 22 is composed of a first adsorption tank 23 and a second adsorption tank 24. The first adsorption tank 23 and the second adsorption tank 24 are tanks that receive gas from the first switching unit 21 and adsorb carbon dioxide from the gas. Gas is alternately supplied to the first adsorption tank 23 and the second adsorption tank 24. A first concentrated gas with an increased carbon dioxide concentration is generated by desorbing the carbon dioxide adsorbed in the first adsorption tank 23 or the second adsorption tank 24. The generated first concentrated gas is supplied to the first filter 31. The first exhaust gas, which has had carbon dioxide adsorbed and has a lower carbon dioxide concentration, is exhausted to the outside of the gas concentrator 1 through the first check valve 33A or the first check valve 33B and the first throttle valve 35. The first adsorption tank 23 and the second adsorption tank 24 contain a carbon dioxide adsorbent using zeolite. Note that the first adsorption tank 23 and the second adsorption tank 24 may contain an adsorbent for oxygen, hydrogen, carbon monoxide, nitrogen, or the like instead of the carbon dioxide adsorbent.

[0031] The first filter 31 filters the first concentrated gas. For example, the first filter 31 filters the adsorbent desorbed from the first adsorption tank 23 and the second adsorption tank 24. The gas filtered by the first filter 31 is supplied to the first decompression pump 25.

[0032] The first decompression pump 25 is a pump that decompresses the gas in the first adsorption tank 23 and the second adsorption tank 24. The gas is supplied from the first decompression pump 25 to the first booster pump 27.

[0033] The first booster pump 27 is a pump that pressurizes the gas flowing toward the buffer tank 41, the third adsorption tank 53 and the fourth adsorption tank 54 of the second concentration section 5.

[0034] The first check valve 33 is a valve that prevents backflow from the intake or exhaust side to the intake side. As the first check valves 33, first check valves 33A, 33B, and 33C are provided in the first concentrating section 2. The first check valve 33A prevents backflow of gas from the first throttle valve 35 side to the first adsorption tank 23 side. The first check valve 33B prevents backflow of gas from the first throttle valve 35 side to the second adsorption tank 24 side. The first check valve 33C prevents backflow of gas from the first buffer tank 41 side to the first boost pump 27 side.

[0035] The first buffer tank 41 is a tank that temporarily stores gas and reduces pressure fluctuations and flow rate fluctuations within the first concentrating section 2. Specifically, the first buffer tank 41 temporarily stores the first concentrated gas generated in the first adsorption tank 23 or the second adsorption tank 24, and supplies the first concentrated gas to the second throttle valve 37.

[0036] The first pressure sensors 29 are sensors that measure pressure. As the first pressure sensors 29, first pressure sensors 29A, 29B, and 29C are provided in the first concentrating section 2. The first pressure sensor 29A measures the pressure in the first adsorption tank 23, the first pressure sensor 29B measures the pressure in the second adsorption tank 24, and the first pressure sensor 29C measures the pressure in the first buffer tank 41.

[0037] The first throttle valve 35 and the second throttle valve 37 are throttle valves configured to adjust the flow rates of the first exhaust gas and the first concentrated gas. The first throttle valve 35 and the second throttle valve 37 are valves that adjust the pressure by adjusting the flow rates of the first exhaust gas and the first concentrated gas. Specifically, the first throttle valve 35 adjusts the flow rate of the first exhaust gas exhausted from the first adsorption tank 23 and the second adsorption tank 24 and exhausts it outside the gas concentrator 1. The second throttle valve 37 adjusts the flow rate of the first concentrated gas supplied from the first buffer tank 41 and supplies it to the second concentrator 5. In the first check valve 33, the smaller the pressure difference between the supply or exhaust side and the intake side, the more likely backflow from the supply or exhaust side to the intake side occurs. By limiting the flow rate with the first throttle valve 35 or the second throttle valve 37 and maintaining a high pressure on the supply or exhaust side, backflow can be suppressed. Specifically, the first throttle valve 35 maintains a high pressure on the exhaust side of the first check valve 33A or the first check valve 33B, thereby preventing backflow of the first exhaust gas toward the first adsorption tank 23 and the second adsorption tank 24.

[0038] In addition, the second throttle valve 37 maintains a constant flow rate of the first concentrated gas supplied from the first concentrating section 2 to the second concentrating section 5. By maintaining a constant flow rate of the first concentrated gas concentrated in the gas concentration process in the second concentrating section 5, the gas concentration process is stabilized and the flow rate of the second concentrated gas exhausted to the outside of the second concentrating section 5 is also stabilized. Furthermore, by maintaining a constant flow rate, carbon dioxide comes into uniform contact with the surface of the adsorbent in the second concentrating section 5, improving adsorption efficiency.

[0039] The first exhaust part 30 is an exhaust port that exhausts the first exhaust gas, the flow rate of which has been adjusted by the first throttle valve 35, to the outside of the gas concentrating device 1.

[0040] The first exhaust valve 39 is a valve for exhausting the first concentrated gas, and is provided downstream of the first boost pump 27 and upstream of the first check valve 33C.

[0041] The first outlet 40 is an outlet through which the first concentrated gas, the flow rate of which has been adjusted by the second throttle valve 37, is supplied from the first concentrating section 2.

[0042] Next, the second concentrating section 5 will be described. The second concentrating section 5 includes a second inlet section 50, a second switching section 51, a second adsorption section 52, a second pressure sensor 59, a second exhaust section 60, a second filter 61, a third filter 62, a second check valve 63, a third throttle valve 65, a second exhaust valve 69, a second buffer tank 71, a pressure reducing valve 73, a flow meter 75, a constant flow valve 77, and a gas exhaust section 70. The second concentrating section 5 produces a second concentrated gas from the first concentrated gas, in which the concentration of carbon dioxide is further increased.

[0043] Of the components of the second concentrating section 5, duplicated descriptions will be omitted as appropriate for components that are similar to those of the first concentrating section 2. That is, the second switching section 51 can be the first switching section 21, the third adsorption tank 53 and the fourth adsorption tank 54 can be the first adsorption tank 23 and the second adsorption tank 24, the second pressure sensor 59 can be the first pressure sensor 29, the second exhaust section 60 can be the first exhaust section 30, the second filter 61 can be the first filter 31, the second check valve 63 can be the first check valve 33, the third throttle valve 65 can be the first throttle valve 35, the second exhaust valve 69 can be the first exhaust valve 39, and the second buffer tank 71 can be the first buffer tank 41, and therefore duplicated descriptions will be omitted as appropriate.

[0044] The second inlet section 50 is an intake port through which the first concentrated gas supplied from the first outlet section 40 is supplied into the second concentration section 5 .

[0045] The second decompression pump 55 is a pump that decompresses the gas in the third adsorption tank 53 and the fourth adsorption tank 54. The gas is supplied from the first decompression pump 25 to the first booster pump 27.

[0046] The second booster pump 57 is a pump for pressurizing the second concentrated gas and discharging it to the outside of the gas concentrating apparatus 1 .

[0047] The volume of gas in the first concentration section 2 is different from the volume of gas in the second concentration section 5. Specifically, the volume of gas in the second concentration section 5 is smaller than the volume of gas in the first concentration section 2. Because the volume of gas in the second concentration section 5 is smaller than the volume of gas in the first concentration section 2, the volume of gas that requires pressure control is reduced, and therefore the output of each pump 9 that controls the pressure in the first concentration section 2 can be reduced.

[0048] The second adsorption unit 52 adsorbs and desorbs carbon dioxide from the first concentrated gas to produce a second concentrated gas. The second adsorption unit 52 includes a third adsorption tank 53 and a fourth adsorption tank 54. The volume of the third adsorption tank 53 or the volume of the fourth adsorption tank 54 is smaller than the volume of the first adsorption tank 23 or the volume of the second adsorption tank 24. For example, the volume of the third adsorption tank or the fourth adsorption tank may be one-half, two-thirds, one-third, three-quarters, four-fifths, or four-thirds of the volume of the first adsorption tank or the second adsorption tank, and preferably is less than four-fifths and more than one-fifth. More preferably, the volume of the third adsorption tank or the fourth adsorption tank is less than three-quarters and more than one-half of the volume of the first adsorption tank or the second adsorption tank. The first concentrated gas has a higher carbon dioxide concentration than the gas drawn into the first concentrating section 2 from outside the gas concentrator 1, i.e., it has a larger number of carbon dioxide molecules per specific volume. Therefore, the volume required to concentrate the first concentrated gas in the third adsorption tank 53 or the fourth adsorption tank 54 is smaller than the volume required to concentrate the gas drawn into the gas concentrator 1 from outside the first adsorption tank 23 or the second adsorption tank 24. A smaller tank volume allows for lower costs for the tank itself compared to a larger tank volume. Furthermore, the volume of gas requiring pressure control is smaller, allowing for reduced output of each pump. In other words, the output of the second decompression pump 55 may be smaller than the output of the first decompression pump 25.

[0049] The third filter 62 filters the second concentrated gas. For example, the third filter 62 filters out dust particles and the like in the buffer. The gas filtered by the third filter 62 is supplied to the pressure reducing valve 73.

[0050] The volume of the second buffer tank 71 is smaller than the volume of the first buffer tank 41. For example, the volume of the second buffer tank 71 may be one-half, two-thirds, one-third, three-quarters, four-fifths, or four-thirds of the volume of the first buffer tank 41, and preferably, it may be four-fifths or less and one-fifth or more. More preferably, the volume of the second buffer tank 71 is three-quarters or less and one-half or more of the volume of the first buffer tank 41. The smaller the tank volume, the lower the cost of the tank itself can be compared to when the tank volume is large, and the smaller the volume of gas that requires pressure control, allowing the output of each pump to be reduced.

[0051] The pressure reducing valve 73 reduces the pressure of the second concentrated gas. The pressure reducing valve 73 may be an electronic expansion valve whose opening is adjustable, or a solenoid valve. When the pressure reducing valve 73 is a solenoid valve, it can be switched between a fully open state and a state in which the opening is reduced so as to reduce the pressure of the second concentrated gas. The second concentrated gas reduced in pressure by the pressure reducing valve 73 is supplied to a flow meter 75.

[0052] The flow meter 75 detects the flow rate of the second concentrated gas. The second concentrated gas whose flow rate has been detected by the flow meter 75 is supplied to a constant flow valve 77.

[0053] The constant flow valve 77 limits the maximum flow rate of the second concentrated gas passing through it. The second concentrated gas is supplied from the constant flow valve 77 to the gas exhaust section 70.

[0054] The gas exhaust unit 70 exhausts the second concentrated gas from inside the gas concentrating device 1 to outside the gas concentrating device 1. The exhausted second concentrated gas may be stored in a tank or the like, or may be used as appropriate.

[0055] Next, the control device 8 will be described. The control device 8 controls each part of the gas concentrating device 1. The control device 8 is partially or entirely composed of analog circuits, or composed of a digital processor or memory. The control device 8 includes a communication unit 81, a control unit 83, and a storage unit 85 as functional blocks.

[0056] The communication unit 81 of the control device 8 transmits and receives signals. The communication unit 81 transmits and receives signals, for example, to and from the outside of the gas concentrating device 1, or transmits and receives signals to and from components within the gas concentrating device 1, such as the pressure sensors 29 and 59 and the flow meter 75. The control unit 83 of the control device 8 performs various controls based on signals received by the gas concentrating device 1 from the outside or the inside, measured values ​​or control target values ​​such as flow rate and pressure stored in the memory unit 85, or various control parameters. The control parameters include, for example, the open / closed state of each solenoid valve of the first switching unit 21 or the second switching unit 51, the open / closed state of the first exhaust valve 39 and the second exhaust valve 69, etc. The memory unit 85 of the control device 8 stores the measured values ​​or control target values, or various control parameters.

[0057] The control unit 83 of the control device 8 controls the pump 9 to adjust the pressure in the first concentrating unit 2 and the pressure in the second concentrating unit 5. Specifically, the control unit 83 controls the first decompression pump 25 and the air pump 11 to adjust the pressure in the first concentrating unit 2. The control unit 83 also controls the second decompression pump 55, the first boost pump 27, and the second boost pump 57 to adjust the pressure in the second concentrating unit 5. The control unit 83 also controls the first switching unit to switch the supply destination of the gas, and the second switching unit to switch the supply destination of the first concentrated gas. Specifically, the control unit 83 controls the open / close states of the first solenoid valves 21A, 21B, 21C, and 21D of the first switching unit 21. The control unit 83 controls the open / close states of each solenoid valve to control the supply of gas to or from the first adsorption tank 23 or the second adsorption tank 24. Similarly, the control unit 83 controls the open / close states of second solenoid valves 51A, 51B, 51C, and 51D of the second switching unit 51, thereby controlling the supply destination of the gas to the third adsorption tank 53 or the fourth adsorption tank 54. Furthermore, the control unit 83 controls the first switching unit 21 and the first exhaust valve 39 in cooperation with each other to adjust the timing of exhausting the gas and the first concentrated gas. Specifically, the control unit 83 controls the open / close states of the solenoid valves of the first switching unit 21 and the first exhaust valve 39, thereby adjusting the timing of exhausting the gas and the first concentrated gas. Similarly, the control unit 83 controls the second switching unit 51 and the second exhaust valve 69 in cooperation with each other to adjust the timing of exhausting the first concentrated gas and the second concentrated gas.

[0058] <Example of operation> Gas concentration is performed, for example, as follows. Gas drawn in from outside the gas concentrator 1 by the air pump 11 is supplied to the first adsorption tank 23. The carbon dioxide adsorbent in the first adsorption tank 23 adsorbs carbon dioxide from the gas supplied to the first adsorption tank 23. The first exhaust gas, which has had carbon dioxide adsorbed and has a lower carbon dioxide concentration, is exhausted to the outside of the gas concentrator 1 through the first exhaust section 30. Next, the pressure of the gas in the first adsorption tank 23 is reduced by the first decompression pump 25, causing carbon dioxide to be desorbed from the carbon dioxide adsorbent in the first adsorption tank 23. Because carbon dioxide is desorbed from the adsorbent, the adsorbent can adsorb carbon dioxide again. In other words, the carbon dioxide adsorbent is regenerated by the desorption of carbon dioxide. The carbon dioxide-containing gas desorbed from the first adsorption tank 23 is a first concentrated gas, which has a higher carbon dioxide concentration than the gas supplied from outside the gas concentrator 1. The first concentrated gas is pressurized by the first booster pump 27 and supplied to the second concentrating section 5. The first concentrated gas introduced into the second concentrating section 5 is supplied to the third adsorption tank 53. The carbon dioxide adsorbent in the third adsorption tank 53 adsorbs carbon dioxide from the gas supplied to the third adsorption tank 53. The second exhaust gas, which has had carbon dioxide adsorbed and has a lower carbon dioxide concentration, is exhausted to the outside of the gas concentrating apparatus 1 through the second exhaust section 60. Next, the pressure of the gas in the third adsorption tank 53 is reduced by the second decompression pump 55, thereby desorbing the carbon dioxide from the third adsorption tank 53. The gas containing carbon dioxide desorbed from the third adsorption tank 53 is a second concentrated gas which has a higher carbon dioxide concentration than the first concentrated gas supplied from the first concentrating section 2. This second concentrated gas is pressurized by the second booster pump 57 and exhausted to the outside of the gas concentrating apparatus 1. The adsorption and desorption of carbon dioxide is carried out alternately between the first adsorption tank 23 and the second adsorption tank 24, and alternately between the third adsorption tank 53 and the fourth adsorption tank .

[0059] <Processing flow> FIG. 2 is a timing chart showing an example of the process flow in the first concentrating section 2 of the gas concentrating apparatus 1 of FIG. 1. FIG. 2 chronologically shows the open / close states (OPEN or CLOSE) of the first solenoid valves 21A, 21B, 21C, and 21D of the first switching section 21, and the open / close state (OPEN or CLOSE) of the first exhaust valve 39. FIG. 2 also chronologically shows which stage the first adsorption tank 23 and the second adsorption tank 24 are in: adsorption, pressure equalization, or desorption. FIG. 3 is a diagram showing the gas flow in the first concentrating section 2 at time T11. FIG. 4 is a diagram showing the gas flow in the first concentrating section 2 at time T14. The flow of carbon dioxide adsorption and desorption alternately performed between the first adsorption tank 23 and the second adsorption tank 24 will be described with reference to FIGS. 1, 2, 3, and 4.

[0060] At time T11, first solenoid valve 21A is open, first solenoid valve 21B is closed, first solenoid valve 21C is closed, and first solenoid valve 21D is open, so that first adsorption tank 23 is in an adsorption state and second adsorption tank 24 is in a desorption state. As shown in FIG. 3 , gas drawn from outside gas concentrator 1 by air pump 11 is supplied to first adsorption tank 23. First adsorption tank 23 adsorbs carbon dioxide from the supplied gas. The first exhaust gas, which has absorbed carbon dioxide and has a reduced carbon dioxide concentration, is discharged outside gas concentrator 1 through first exhaust section 30. Meanwhile, the pressure of the gas in second adsorption tank 24 is reduced by first decompression pump 25, causing carbon dioxide to desorb from the carbon dioxide adsorbent in second adsorption tank 24 to produce a first concentrated gas. The first concentrated gas is supplied to second concentrator 5 through first outlet section 40. By desorption of carbon dioxide, the carbon dioxide adsorbent in the second adsorption tank 24 is regenerated.

[0061] Returning to FIG. 2 , at time t111, first solenoid valve 21B switches to the open state, and first solenoid valve 21D switches to the closed state. At time T12, the first adsorption tank 23 and the second adsorption tank 24 are in a pressure-equalized state. Gas drawn in from outside the gas concentrating apparatus 1 by air pump 11 is supplied to the first adsorption tank 23 and the second adsorption tank 24. Furthermore, the gas in the first adsorption tank 23 flows into the second adsorption tank 24, which was in a reduced-pressure state at time T11, and the pressure in the first adsorption tank 23 and the pressure in the second adsorption tank 24 become equal. Here, because first solenoid valves 21C and 21D are in the closed state, gas is not supplied to the second concentrating section 5, and gas is exhausted from first exhaust section 30.

[0062] At time t112, first solenoid valve 21A switches to the closed state, and first solenoid valve 21C switches to the open state. At time T13, first adsorption tank 23 is in the desorption state, and second adsorption tank 24 is in the adsorption state. The adsorption and desorption states of each tank at time T11 are reversed, and first concentrated gas is supplied from first adsorption tank 23 to first filter 31. Also, at time t112, first exhaust valve 39 switches to the open state. By opening first exhaust valve 39, gas on the intake side of first check valve 33C is exhausted, and its pressure decreases. By reducing the pressure on the intake side of first check valve 33, the differential pressure between the intake and supply sides of first check valve 33C is maintained in a state where the supply side is higher, thereby preventing backflow of gas from the supply side to the intake side of first check valve 33C. The exhaustion can prevent the backflow caused by pressure fluctuations when the adsorption and desorption states of each tank are switched.

[0063] At time t113, the first exhaust valve 39 switches to a closed state, and exhaust stops. At time T14, the first adsorption tank 23 remains in the desorption state, and the second adsorption tank 24 remains in the adsorption state. As shown in FIG. 4, gas drawn from outside the gas concentrator 1 by the air pump 11 is supplied to the second adsorption tank 24. The second adsorption tank 24 adsorbs carbon dioxide from the supplied gas. The first exhaust gas, which has absorbed carbon dioxide and has a reduced carbon dioxide concentration, is discharged outside the gas concentrator 1 through the first exhaust section 30. Meanwhile, the pressure of the gas in the first adsorption tank 23 is reduced by the first decompression pump 25, causing the carbon dioxide to desorb from the carbon dioxide adsorbent in the first adsorption tank 23, thereby generating a first concentrated gas. The first concentrated gas is supplied to the second concentrator 5 through the first outlet section 40. The carbon dioxide adsorbent in the first adsorption tank 23 is regenerated by the desorption of carbon dioxide.

[0064] Returning to FIG. 2 , at time t114, first solenoid valve 21A switches to the open state, and first solenoid valve 21C switches to the closed state. At time T15, the first adsorption tank 23 and the second adsorption tank 24 are in a pressure-equalized state. Gas drawn in from outside the gas concentrating apparatus 1 by air pump 11 is supplied to the first adsorption tank 23 and the second adsorption tank 24. Furthermore, the gas in the second adsorption tank 24 flows into the first adsorption tank 23, which was in a reduced-pressure state at time T11, and the pressure in the first adsorption tank 23 and the pressure in the second adsorption tank 24 become equal. Here, because first solenoid valves 21C and 21D are in the closed state, gas is not supplied to the second concentrating section 5, and gas is exhausted from the first throttle valve 35 side.

[0065] At time t115, first solenoid valve 21B switches to the closed state, and first solenoid valve 21D switches to the open state. At time T16, first adsorption tank 23 is in the adsorption state, and second adsorption tank 24 is in the desorption state. The adsorption and desorption states of each tank at time T14 are reversed, and the first concentrated gas is supplied from second adsorption tank 24 to the first filter 31 side. Also at time t115, first exhaust valve 39 switches to the open state.

[0066] At time t116, first exhaust valve 39 switches to the closed state, and exhaust stops. Here, as in the case of T11, first solenoid valve 21A is open, first solenoid valve 21B is closed, first solenoid valve 21C is closed, first solenoid valve 21D is open, first adsorption tank 23 is in the adsorption state, and second adsorption tank 24 is in the desorption state.

[0067] The above process is repeated, and carbon dioxide adsorption and desorption are alternately performed in the first adsorption tank 23 and the second adsorption tank 24 of the first concentration section 2, to generate a first concentrated gas. Here, the adsorption and desorption of carbon dioxide are controlled by switching the first switching section 21 and adjusting the pressure inside the gas concentration apparatus 1 using the air pump 11 and the first decompression pump 25.

[0068] Fig. 5 is a timing chart showing an example of the processing flow in the second concentrating section 5 of the gas concentrating apparatus 1 of Fig. 1. Fig. 5 chronologically shows the open / closed states (OPEN or CLOSE) of second solenoid valves 51A, 51B, 51C, and 51D of second switching section 51, and the open / closed state (OPEN or CLOSE) of second exhaust valve 69. Fig. 5 also chronologically shows whether third adsorption tank 53 and fourth adsorption tank 54 are in the adsorption, pressure equalization, or desorption stage.

[0069] 5, the description of the flow of carbon dioxide adsorption and desorption in the second concentrator 5 that overlaps with the flow of carbon dioxide adsorption and desorption in the first concentrator 2 will be omitted as appropriate. The components of the second concentrator 5 can be replaced with the components corresponding to those in the first concentrator 2. That is, since similar configurations can be adopted, such as the air pump 11 being the first boost pump 27, the first adsorption tank 23 being the third adsorption tank 53, the second adsorption tank 24 being the fourth adsorption tank 54, the first solenoid valve 21A being the second solenoid valve 51A, the first solenoid valve 21B being the second solenoid valve 51B, the first solenoid valve 21C being the second solenoid valve 51C, the first solenoid valve 21D being the second solenoid valve 51D, the first check valve 33C being the second check valve 63C, the first exhaust valve 39 being the second exhaust valve 69, times T11 to T16 being times T21 to T26, respectively, and times t100 to t126 being times t200 to t226, duplicated explanations will be omitted as appropriate.

[0070] Similar to the first concentrating section 2, carbon dioxide adsorption and desorption are alternately carried out in the third adsorption tank 53 and the fourth adsorption tank 54 of the second concentrating section 5, to generate a second concentrated gas. Here, the adsorption and desorption of carbon dioxide in the second adsorption section 52 of the second concentrating section 5 is controlled by switching the second switching section 51 and adjusting the pressure inside the second concentrating section 5 by the first boost pump 27 and the second decompression pump 55.

[0071] <Action and effect> As described above, the gas concentration device 1 of this embodiment comprises a gas intake section 10 that takes in gas, a first concentration section 2 that produces a first concentrated gas with an increased concentration of carbon dioxide from the taken-in gas, a second concentration section 5 that produces a second concentrated gas with an even increased concentration of carbon dioxide from the first concentrated gas, and a gas exhaust section 70 that exhausts the second concentrated gas to the outside.

[0072] According to this configuration, gas concentration is performed in two stages, making it possible to recover carbon dioxide at a higher concentration than when carbon dioxide is recovered from gas through a single-stage gas concentration process.

[0073] In addition, in the gas concentration device 1, the first concentration section 2 has a first adsorption section 22 that adsorbs and desorbs carbon dioxide from the gas to produce a first concentrated gas, and the second concentration section 5 has a second adsorption section 52 that adsorbs and desorbs carbon dioxide from the first concentrated gas to produce a second concentrated gas, and further includes a pump 9 that is configured to be able to adjust the pressure within the first concentration section 2 and the pressure within the second concentration section 5, and a control device 8 that controls the pump 9 and adjusts the pressure within the first concentration section 2 and the pressure within the second concentration section 5.

[0074] According to this configuration, a gas containing carbon dioxide can be obtained more quickly than when gas concentration is performed by thermal control.

[0075] In addition, in the gas concentration device 1, the first concentration section 2 has a first switching section 21 configured to be able to switch the supply destination of the gas, the first adsorption section 22 has a first adsorption tank 23 and a second adsorption tank 24, the second concentration section 5 has a second switching section 51 configured to be able to switch the supply destination of the first concentrated gas, the second adsorption section 52 has a third adsorption tank 53 and a fourth adsorption tank 54, and the control device 8 controls the first switching section 21 to switch the supply destination of the gas and controls the second switching section 51 to switch the supply destination of the first concentrated gas.

[0076] With this configuration, gas can be concentrated alternately in the two adsorption tanks of each enrichment section, making gas concentration more efficient than when each enrichment section has only one adsorption tank.

[0077] Furthermore, in the gas concentrator 1, the volume of the gas in the first concentrator 2 and the volume of the gas in the second concentrator 5 are different.

[0078] According to this configuration, when the volume of gas in the second concentration section is larger than the volume of gas in the first concentration section, a larger amount of second concentrated gas can be obtained compared to when the volume of gas in the second concentration section is the same as the volume of gas in the first concentration section, and when the volume of gas in the second concentration section is smaller than the volume of gas in the first concentration section, the size of the device can be reduced and costs can be kept down.

[0079] Furthermore, in the gas concentrating apparatus 1, the volume of the third adsorption tank 53 or the volume of the fourth adsorption tank 54 is smaller than the volume of the first adsorption tank 23 or the volume of the second adsorption tank 24.

[0080] With this configuration, the cost of the tank itself can be reduced compared to when the adsorption tank has a large volume, and since the volume of gas that needs to be pressure controlled is also small, it is also possible to reduce the output of the pump used for pressure control.

[0081] In addition, in the gas concentrating apparatus 1, the volume of the third adsorption tank 53 or the volume of the fourth adsorption tank 54 is not more than three-quarters and not less than one-half of the volume of the first adsorption tank 23 or the second adsorption tank 24.

[0082] With this configuration, the cost of the tank itself can be reduced compared to when the adsorption tank has a large volume, and since the volume of gas that needs to be pressure controlled is also small, it is also possible to reduce the output of the pump used for pressure control.

[0083] In addition, in the gas concentration device 1, the first concentration section 2 has a first buffer tank 41 that alleviates pressure fluctuations within the first concentration section 2, and the second concentration section 5 has a second buffer tank 71 that alleviates pressure fluctuations within the second concentration section 5, and the volume of the second buffer tank 71 is smaller than the volume of the first buffer tank 41.

[0084] With this configuration, the cost of the buffer tank itself can be reduced compared to when the volume of the buffer tank is large, and since the volume of gas that needs to be pressure controlled is also small, it is also possible to lower the output of the pump used for pressure control.

[0085] Moreover, the gas concentrating device 1 further includes a throttle valve configured to be able to adjust the flow rate of the first concentrated gas.

[0086] According to this configuration, the gas concentration process in the second concentration section is stable, and the flow rate of the second concentrated gas discharged to the outside of the second concentration section is also stable, compared to when the flow rate of the first concentrated gas fluctuates unstably.

[0087] In addition, in the gas concentration device 1, the first concentration section 2 has a first exhaust valve 39 that exhausts the first concentrated gas, and the second concentration section 5 has a second exhaust valve 69 that exhausts the second concentrated gas, and the control device 8 controls the first switching section 21 and the first exhaust valve 39 in conjunction with each other to adjust the timing of the exhaust of the gas and the exhaust of the first concentrated gas, and also controls the second switching section 51 and the second exhaust valve 69 in conjunction with each other to adjust the timing of the exhaust of the first concentrated gas and the exhaust of the second concentrated gas.

[0088] According to this configuration, pressure fluctuations within the gas concentrating device can be alleviated compared to when exhaust is not performed.

[0089] In addition, in the gas concentrating device 1, the first concentrating section 2 has a first filter 31 that filters the first concentrated gas, and the second concentrating section 5 has a second filter 61 that filters the second concentrated gas.

[0090] This configuration can prevent desorbed adsorbents and the like from being mixed into the recovered gas, compared to when there is no filter.

[0091] <Modification> The present invention is not limited to the above-described embodiments. In other words, designs that are appropriately modified by a person skilled in the art from the above-described specific examples are also included within the scope of the present invention as long as they include the features of the present invention. Furthermore, the elements of the above-described embodiments and the following modifications can be combined to the extent technically possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention.

[0092] For example, although the embodiment has been described as an example of the gas concentrator 1 that performs gas concentration in two stages, the gas concentrator 1 may also be configured to perform gas concentration in three stages. For example, the gas concentrator 1 may further include a third concentration unit that generates a third concentrated gas with an increased carbon dioxide concentration from the second concentrated gas. In this case, a gas containing a higher concentration of carbon dioxide can be obtained compared to when gas is concentrated in two stages.

[0093] In addition, although the embodiment employs a method for concentrating gas by controlling the pressure of parallel adsorption tanks, other methods of concentrating gas may be used, such as chemical adsorption, chemical absorption, membrane separation, cryogenic separation, etc. For example, gas concentration by thermal control may be performed in two stages.

[0094] Furthermore, in the embodiment, the volume of the third adsorption tank 53 or the volume of the fourth adsorption tank 54 is shown as being smaller than the volume of the first adsorption tank 23 or the volume of the second adsorption tank 24, but the volume of the third adsorption tank 53 or the volume of the fourth adsorption tank 54 may be the same as or larger than the volume of the first adsorption tank 23 or the second adsorption tank 24. When the volume of the third adsorption tank 53 or the fourth adsorption tank 54 is large, a larger amount of second concentrated gas can be obtained in one cycle of carbon dioxide adsorption and desorption.

[0095] Furthermore, the adsorption and desorption times T21, T23, T24, and T26 in the second concentrating section 5 may be longer than, the same as, or shorter than the adsorption and desorption times T11, T13, T24, and T26 in the first concentrating section 2. For example, the time T24 at which the third adsorption tank 53 enters the desorption state may be longer than, shorter than, or the same as the time T14 at which the first adsorption tank 23 enters the desorption state. For example, by setting each of the times T11 to T16 to be shorter, faster gas concentration is possible. For example, when comparing the time required to reach adsorption breakthrough in a single stage to obtain a desired carbon dioxide concentration from the carbon dioxide concentration in the atmosphere with the total time required to reach adsorption breakthrough in the first and second concentrated gases in two stages, the latter may be faster. Furthermore, the pressure controlled in the first concentrating section 2 and the pressure controlled in the second concentrating section 5 may be the same or different. For example, the pressure in the third adsorption tank 53 at time T24 when the third adsorption tank 53 enters the desorption state may be higher, lower, or the same as the pressure in the first adsorption tank 23 at time T14 when the first adsorption tank 23 enters the desorption state. Furthermore, for example, the first cycle, which is the total time from T11 to T16 in the first concentrating section 2, may be longer, shorter, or the same as the second cycle, which is the total time from T21 to T26 in the second concentrating section 5. The above-mentioned time, pressure, cycle, etc. may be adjusted according to the desired carbon dioxide concentration, yield, stability of yield, etc. Furthermore, the timing of exhaust by opening and closing the first exhaust valve 39 or the second exhaust valve 69 may also be adjusted according to the above-mentioned time and pressure changes. Adjusting the exhaust timing allows for stable pressure balance within the gas concentrating apparatus 1.

[0096] In addition, although the configuration in which the second throttle valve 37 for adjusting the flow rate of the first concentrated gas is provided in the first concentrating section 2 has been shown as an example, the second throttle valve 37 may be provided in the second concentrating section 5, or may be provided independently of the first concentrating section 2 and the second concentrating section 5. Furthermore, the flow rate may be changed in response to switching between opening and closing of the first switching section 21 and the second switching section 51, or a change in pressure caused by the pump 9.

[0097] In addition, although an example has been given in which the control unit 83 controls the pressure in the first concentration unit 2 and the pressure in the second concentration unit 5 at independent timings, the timings of the two-stage gas concentration may also be controlled in conjunction with each other.

[0098] Furthermore, the volume of the first adsorption tank 23 and the volume of the second adsorption tank 24 may be the same, or one may be larger. Furthermore, the volume of the third adsorption tank 53 and the volume of the fourth adsorption tank 54 may be the same, or one may be larger.

[0099] In addition, in the present embodiment, the first enrichment section 2 and the second enrichment section 5 each have two adsorption tanks as an example, but the number of adsorption tanks in each enrichment section may be one or three or more. For example, the first enrichment section 2 may have three adsorption tanks, and the second enrichment section 5 may have four adsorption tanks.

[0100] In addition, although the configuration in which the volume of gas in the second concentrator 5 is smaller than the volume of gas in the first concentrator 2 has been shown as an example, the volume of gas in the second concentrator 5 may be larger than or the same as the volume of gas in the first concentrator 2. When the volume of gas in the second concentrator 5 is larger than the volume of gas in the first concentrator 2, a larger amount of second-concentrated gas can be obtained in one cycle of carbon dioxide adsorption and desorption. In addition, although the configuration in which the adsorption tanks 23, 24, 53, and 54 and the buffer tanks 41 and 71 have different volumes has been shown as an example, the volumes of the components constituting the flow paths in the gas concentrator 1 may also be different. For example, the gas volumes may differ depending on the diameters of the tubes, hoses, and connectors constituting the flow paths in the gas concentrator 1.

[0101] Furthermore, the flow meter 75 may be provided, for example, before or after the first throttle valve 35, the second throttle valve 37, and the third throttle valve 65. The control device 8 may control each solenoid valve or each pump based on the measured flow rate, and adjust the pressure within the gas concentration device 1 and the supply destination of the gas or each concentrated gas. [Explanation of symbols]

[0102] 1: Gas concentrator 2: 1st concentration section 5:Second concentration section 10: Gas intake section 70: Gas exhaust section

Claims

1. a gas intake section for taking in gas; a first concentration section that generates a first concentrated gas in which the concentration of carbon dioxide is increased from the introduced gas; a second concentration section for generating a second concentrated gas in which the concentration of carbon dioxide is further increased from the first concentrated gas; a gas exhaust unit that exhausts the second concentrated gas to the outside; a pump configured to adjust the pressure in the first rectifying section and the pressure in the second rectifying section; a control device that controls the pump and adjusts the pressure in the first rectifying section and the pressure in the second rectifying section; a throttle valve configured to adjust the flow rate of the first concentrated gas supplied from the first concentration section to the second concentration section; Equipped with the first concentration unit includes a first adsorption unit having a first adsorption tank and a second adsorption tank, which adsorbs and desorbs carbon dioxide from the gas to generate the first concentrated gas, and a first switching unit configured to be able to switch a supply destination of the gas, the second concentration unit includes a second adsorption unit having a third adsorption tank and a fourth adsorption tank, which adsorbs and desorbs carbon dioxide from the first concentrated gas to generate the second concentrated gas, and a second switching unit configured to be able to switch a supply destination of the first concentrated gas, The control device controls the first switching unit to switch the supply destination of the gas, and controls the second switching unit to switch the supply destination of the first concentrated gas. Gas concentrator.

2. The volume of the gas in the first enrichment section is different from the volume of the gas in the second enrichment section. The gas concentrator according to claim 1 .

3. the volume of the third adsorption tank or the volume of the fourth adsorption tank is smaller than the volume of the first adsorption tank or the volume of the second adsorption tank; The gas concentrator according to claim 2 .

4. the volume of the third adsorption tank or the volume of the fourth adsorption tank is not more than three-quarters and not less than one-half of the volume of the first adsorption tank or the second adsorption tank; The gas concentrator according to claim 3 .

5. the first enrichment section includes a first buffer tank that reduces pressure fluctuations within the first enrichment section; the second enrichment section includes a second buffer tank that reduces pressure fluctuations within the second enrichment section; The volume of the second buffer tank is smaller than the volume of the first buffer tank. The gas concentrator according to claim 1 .

6. the first concentration section has a first exhaust valve that exhausts the first concentrated gas, the second concentrating section has a second exhaust valve that exhausts the second concentrated gas, the control device controls the first switching unit and the first exhaust valve in cooperation with each other to adjust the timing of exhausting the gas and the first concentrated gas, and controls the second switching unit and the second exhaust valve in cooperation with each other to adjust the timing of exhausting the first concentrated gas and the second concentrated gas. The gas concentrator according to claim 1 .

7. the first concentration unit has a first filter that filters the first concentrated gas, the second concentration unit has a second filter that filters the second concentrated gas. The gas concentrator according to claim 1 .

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