Separation System

Abstract

To provide a separation system that can be stopped without flowing unreacted fluid and insufficiently separated fluid to the outside.SOLUTION: A separation system 1 is provided with: a first separator 10 into which fluid containing a hydrogen isotope flows and which flows out fluid that is lower in hydrogen isotope content rate than the fluid including the hydrogen isotope; a gas / liquid separator 20 that separates the fluid flowing out from the first separator 10 into gas and liquid; a second separator 30 that generates electric power using the gas discharged from the gas / liquid separator 20; a water electrolyzing device 40 that electrolyzes water; a first storage container 60 that stores raw materials electrolyzed by the water electrolyzing device 40; a refluxing passage 100A through which the liquid discharged from the gas / liquid separator 20 is refluxed to the first storage container 60; switching means 110A that switches between a connected state where the gas / liquid separator 20 is connected to the reflux passage 100A and a non-connected state where the connection state is released; and a control part 140. When stopping the operation of the separation system 1, the control part 140 makes the switching means 110A switch the non-connected state into the connected state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a separation system. [Background technology]

[0002] A known technique for enriching the hydrogen isotopes deuterium and tritium is to use multiple fuel cells connected in series, each of which generates electricity independently, separate the hydrogen isotopes from a gas containing the hydrogen isotopes, and extract the isotopes as liquid water (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 194182 Summary of the Invention [Problem to be solved by the invention]

[0004] In a system for separating hydrogen isotopes, when the system is shut down, it is necessary to shut down the system without leaking to the outside any unreacted fluid remaining in the fuel cell that has not been used to generate electricity, or any fluid in which hydrogen isotopes have not been sufficiently separated. An object of the present invention is to provide a separation system that can shut down the system without causing unreacted fluid or insufficiently separated fluid to flow outside. [Means for solving the problem]

[0005] The present invention has the following aspects. [1] A separation system comprising: a first separation device into which a fluid containing hydrogen isotopes is introduced and which outputs a fluid having a lower hydrogen isotope content than the fluid; a gas-liquid separator located downstream of the first separation device and which separates the fluid flowing out of the first separation device into gas and liquid; a second separation device located downstream of the gas-liquid separator and which generates electricity using the gas discharged from the gas-liquid separator; a water electrolysis device located upstream of the first separation device and which electrolyzes water; a first storage container connected to the water electrolysis device and which stores raw material to be electrolyzed in the water electrolysis device; a return flow path through which liquid discharged from the gas-liquid separator is returned to the first storage container; switching means for switching between a connected state in which the gas-liquid separator and the return flow path are connected and a disconnected state in which the connection state is released; and a control unit, wherein the control unit switches to the connected state using the switching means when stopping operation of the separation system. With this configuration, when the separation system is stopped, any unreacted fluid or insufficiently separated fluid remaining in the first separation device can be returned to the first storage container, and the separation system can be stopped without the unreacted fluid or insufficiently separated fluid leaking to the outside.

[0006] [2] In the aspect [1] above, the system may further include a second storage container for storing the liquid discharged from the gas-liquid separator, and a supply path for supplying the liquid discharged from the gas-liquid separator to the second storage container, the switching means being provided in the supply path, and the control unit may use the switching means to set the separation system to the disconnected state when the separation system is operating, and set the gas-liquid separator and the second storage container to a connected state. According to this configuration, when the separation system is in operation, the fluid after separation treatment can be stored in the second storage container.

[0007] [3] In the aspect [1] above, when stopping the operation of the separation system, the control unit may stop the first separation device after switching the switching means to the connected state, and operate the second separation device so that the amount of power generated by the second separation device is reduced. This configuration allows the residual pressure in the separation system to be reduced and the separation system to be shut down, and also prevents the fluid containing hydrogen isotopes from leaking from the anode side to the cathode side of the second separation device.

[0008] [4] In the aspect of [3] above, the first separation device and the second separation device each include an electrolyte membrane, an anode catalyst layer and an anode flow path are provided in this order on a first surface of the electrolyte membrane, and a cathode catalyst layer and a cathode flow path are provided in this order on a second surface of the electrolyte membrane, at least one of the first separation device and the second separation device includes a sealing means for sealing off the outflow of fluid from the anode flow path, and the control unit may close the sealing means when stopping operation of the separation system, and operate the second separation device so that the anode side of the electrolyte membrane of the second separation device is at a lower pressure than the cathode side. According to this configuration, in the second separation device, it is possible to further prevent the fluid containing hydrogen isotopes from flowing out from the anode side via the cathode side to the outside.

[0009] [5] In the aspect [4] above, when stopping the operation of the separation system, the control unit may operate the second separation device so that the amount of current generated is lower than the power generation state before the second separation device was stopped. This configuration can suppress deterioration of the electrolyte membrane of the second separation device.

[0010] [6] In the above aspect [4] or [5], when stopping the operation of the separation system, the control unit may stop the second separation device after the anode side of the second separation device becomes lower in pressure than the cathode side. According to this configuration, the second separation device can be stopped after the fluid has been sufficiently consumed in the second separation device.

[0011] [7] In the aspect [6] above, the gas-liquid separator is provided with a cooling unit that cools the fluid supplied to the gas-liquid separator, and the control unit may, when the separation system is operating, cool the fluid supplied to the gas-liquid separator using the cooling unit, and when the operation of the separation system is stopped, stop cooling of the fluid by the cooling unit after the first separation device and the second separation device have stopped. According to this configuration, when the separation system is stopped, the fluid flowing out of the first separation device is separated into gas and liquid while the second separation device is operating, so even if fluid is present in the piping of each separation device, gases such as water vapor are removed, thereby preventing freezing in the piping. Furthermore, even if the fluid remaining in the piping of each separation device contains HDO, the gas-liquid separator cools the fluid, condenses the HDO, and separates it, so the separation function can be maintained even when the separation system is stopped.

[0012] Further, another aspect of the present invention is as follows. [8] A method for shutting down a separation system according to one aspect of the present invention includes a first separation device into which a fluid containing hydrogen isotopes is introduced and which outputs a fluid having a lower hydrogen isotope content than the first fluid; a gas-liquid separator disposed downstream of the first separation device and which separates the fluid flowing out of the first separation device into gas and liquid; a second separation device disposed downstream of the gas-liquid separator and which generates electricity using the gas discharged from the gas-liquid separator; a water electrolyzer disposed upstream of the first separation device and which electrolyzes water; a first storage container connected to the water electrolyzer and which stores raw material to be electrolyzed in the water electrolyzer; a reflux path for refluxing the liquid discharged from the gas-liquid separator to the first storage container; switching means for switching between a connected state in which the gas-liquid separator and the reflux path are connected and a disconnected state in which the connected state is released; and a control unit, wherein the control unit switches the switching means to the connected state when stopping operation of the separation system. With this configuration, when the separation system is stopped, any unreacted fluid or insufficiently separated fluid remaining in the first separation device can be returned to the first storage container, and the separation system can be stopped without the unreacted fluid or insufficiently separated fluid leaking to the outside.

[0013] [9] In the aspect [8] above, the separation system further includes a second storage container for storing the liquid discharged from the gas-liquid separator, and a supply path for supplying the liquid discharged from the gas-liquid separator to the second storage container, and the switching means is provided in the supply path, and the control unit may cause the switching means to be in the disconnected state when the separation system is operating, and the gas-liquid separator and the second storage container to be in the connected state. According to this configuration, when the separation system is in operation, the fluid after separation treatment can be stored in the second storage container.

[0014]

[10] In the aspect [8] above, when the control unit stops the operation of the separation system, after the switching means has set the separation system to the connected state, the control unit may stop the first separation device and operate the second separation device so that the amount of power generated by the second separation device is reduced. This configuration allows the residual pressure in the separation system to be reduced and the separation system to be shut down, and also prevents the fluid containing hydrogen isotopes from leaking from the anode side to the cathode side of the second separation device.

[0015]

[11] In the aspect

[10] above, the first separation device and the second separation device each include an electrolyte membrane, an anode catalyst layer and an anode flow path are provided in this order on a first surface of the electrolyte membrane, and a cathode catalyst layer and a cathode flow path are provided in this order on a second surface of the electrolyte membrane, and at least one of the first separation device and the second separation device includes a sealing means for sealing off the outflow of fluid from the anode flow path, and when the operation of the separation system is stopped, the control unit may close the sealing means and operate the second separation device so that the anode side of the electrolyte membrane of the second separation device is at a lower pressure than the cathode side. This configuration can further prevent the fluid containing hydrogen isotopes from leaking from the anode side to the cathode side to the outside.

[0016]

[12] In the aspect

[11] above, when the control unit stops operation of the separation system, the control unit may operate the second separation device so that the amount of current generated is lower than the power generation state before the second separation device was stopped. This configuration can suppress deterioration of the electrolyte membrane of the second separation device.

[0017]

[13] In the above aspect

[11] or

[12] , when the control unit stops the operation of the separation system, the control unit may stop the second separation device after the anode side of the second separation device becomes less than a predetermined pressure. According to this configuration, the second separation device can be stopped after the fluid has been sufficiently consumed in the second separation device.

[0018]

[14] In the aspect

[13] above, the gas-liquid separator is provided with a cooling unit that cools the fluid supplied to the gas-liquid separator, and the control unit may be configured to cool the fluid supplied to the gas-liquid separator by the cooling unit when the separation system is operating, and to stop cooling of the fluid by the cooling unit after the first separation device and the second separation device are stopped when the operation of the separation system is stopped. According to this configuration, when the separation system is stopped, the fluid flowing out of the first separation device is separated into gas and liquid while the second separation device is operating, so even if fluid is present in the piping of each separation device, gases such as water vapor are removed, thereby preventing freezing in the piping. Furthermore, even if the fluid remaining in the piping of each separation device contains HDO, the gas-liquid separator cools the fluid, condenses the HDO, and separates it, so the separation function can be maintained even when the separation system is stopped. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a separation system that can stop the system without causing unreacted fluid or insufficiently separated fluid to flow outside. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a configuration diagram schematically illustrating an example of a separation system of the present invention. [Figure 2] 1 is a flowchart showing an example of the flow of a method for stopping a separation system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a separation system and a stopping method according to an embodiment of the present invention will be described in detail with reference to FIGS. In the present invention, among the three isotopes of hydrogen, deuterium ( 2 H or D) and tritium with mass number 3 ( 3 H or T) are collectively called "hydrogen isotopes," and hydrogen with mass number 1 ( 1 H or H) is called "light hydrogen". Furthermore, gas and liquid are collectively referred to as "fluid." In the present invention, a fluid includes a gas containing a liquid and a liquid containing a gas. As the fluid, a gas or a gas containing a liquid is preferred. Furthermore, the period from when a series of operations performed to shut down the operation of the separation system of the present invention is completed to when that series of operations is completed is referred to as "shutdown of the separation system." Specifically, the period from when the water electrolysis device described below is shut down to when the gas-liquid separator described below is shut down is referred to as "shutdown of the separation system." Furthermore, the operation of the separation system before shut down is referred to as "operation of the separation system." In addition, in each drawing used in the following description, characteristic portions may be enlarged for convenience in order to make the features easier to understand, and the dimensional ratios of each component may differ from the actual ones. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to them and can be implemented with appropriate changes within the scope of the present invention.

[0022] "Separation System" FIG. 1 is a schematic diagram showing an example of a separation system of the present invention. The separation system 1 shown in Figure 1 includes a first separation device 10, a gas-liquid separator 20, a second separation device 30, a water electrolysis device 40, a humidifier 50, a first storage container 60, a second storage container 70, a third storage container 80, two supply paths 90A, 90B, two return paths 100A, 100B, two switching means 110A, 110B, and a control unit 140. The water electrolyzer 40, the humidifier 50, the first separator 10, the gas-liquid separator 20, and the second separator 30 are connected in this order from the upstream side by a hydrogen supply flow path 120. The water electrolyzer 40, the humidifier 50, and the first separator 10 or the second separator 30 are connected in this order from the upstream side by an oxygen supply flow path 130.

[0023] <First Separation Device> The first separation device 10 is a device into which a fluid containing hydrogen isotopes (hereinafter also referred to as the "first fluid") flows and from which a fluid having a lower hydrogen isotope content than the first fluid (hereinafter also referred to as the "second fluid") flows out. The first separation device 10 comprises a first fuel cell 11 .

[0024] The first fuel cell 11 is for separating hydrogen isotopes from the first fluid. A known fuel cell can be used as the first fuel cell 11. As a specific example, the first fuel cell 11 includes an electrolyte membrane, and an anode catalyst layer and an anode flow path are provided in this order on a first surface of the electrolyte membrane, and a cathode catalyst layer and a cathode flow path are provided in this order on a second surface. The first fuel cell 11 also includes a pair of separators that sandwich the electrolyte membrane, the anode catalyst layer, the anode flow path, and the cathode catalyst layer and the cathode flow path.

[0025] The electrolyte membrane contains an electrolyte, and when the first separation device 10 is operated, hydrogen and hydrogen isotopes contained in the first fluid diffuse from the anode catalyst layer to the cathode catalyst layer through the electrolyte membrane. The electrolyte membrane is not particularly limited as long as it has an electrolyte, but a solid polymer membrane is preferred because it allows hydrogen and hydrogen isotopes to diffuse easily, making it easier for an isotope exchange reaction (HD+HO⇔H+HDO) to occur at the interface between the electrolyte membrane and the cathode catalyst layer, and improving reaction efficiency. Examples of the solid polymer membrane include a proton-conductive solid polymer membrane and an anion-conductive solid polymer membrane.

[0026] The anode catalyst layer is provided on the first surface of the electrolyte membrane. Examples of catalysts contained in the anode catalyst layer include precious metals such as platinum and ruthenium, transition metals such as nickel and cobalt, and alloys and oxides thereof. Among these, platinum is preferred because it facilitates the isotope substitution reaction (H2 + D2 ⇔ 2DH) and increases the reaction efficiency. The anode flow channel is provided on the surface of the anode catalyst layer opposite the electrolyte membrane and is a region between the anode catalyst layer and the separator.

[0027] The cathode catalyst layer is provided on the second surface of the electrolyte membrane. Examples of catalysts contained in the cathode catalyst layer include precious metals such as platinum and ruthenium, transition metals such as nickel and cobalt, and alloys and oxides thereof. Among these, platinum is preferred because it facilitates isotope exchange reactions in the cathode catalyst layer and at the interface between the electrolyte membrane and the cathode catalyst layer, thereby increasing the reaction efficiency. In particular, it is preferable that the electrolyte membrane is a solid polymer membrane and that the anode catalyst layer and the cathode catalyst layer contain platinum, since this makes the isotope exchange reaction more likely to occur and increases the reaction efficiency. The cathode flow channel is provided on the surface of the cathode catalyst layer opposite the electrolyte membrane and is a region between the cathode catalyst layer and the separator. A first outlet flow path 12 is connected to the outlet of the cathode flow path, and allows a sixth fluid (described later) to flow out of the cathode flow path.

[0028] The separators are provided on the outside of the anode flow channel and the cathode flow channel, respectively. The separator may be made of, for example, styrene, titanium, or carbon.

[0029] When the electrolyte membrane, anode catalyst layer, anode flow path, cathode catalyst layer, cathode flow path and separator are considered to be one cell (fuel cell), the first fuel cell 11 may be composed of one fuel cell, or may be an assembly of multiple fuel cell cells (fuel cell stack).

[0030] <Gas-liquid separator> The gas-liquid separator 20 is provided downstream of the first separation device 10 and separates the second fluid flowing out from the first separation device 10 into gas and liquid. The gas-liquid separator 20 preferably includes a cooling unit (not shown) that cools the second fluid supplied to the gas-liquid separator 20. A gas-liquid separator that includes a cooling unit is also particularly referred to as a "cooling gas-liquid separator." The second fluid is separated in the gas-liquid separator 20 into a gas (hereinafter also referred to as a "third fluid") and a liquid (hereinafter also referred to as a "fourth fluid").

[0031] <Second Separation Device> The second separation device 30 is provided downstream of the gas-liquid separator 20, and generates power using the gas (third fluid) discharged from the gas-liquid separator 20. In other words, the separation system 1 shown in Fig. 1 also functions as a separation and power generation system. The second separation device 30 comprises a second fuel cell 31 and a sealing means 33 .

[0032] The second fuel cell 31 generates electricity and water using the third fluid and oxygen, and hydrogen isotopes are separated from the third fluid during the power generation. A known fuel cell can be used as the second fuel cell 31. As a specific example, the second fuel cell 31 includes an electrolyte membrane, and an anode catalyst layer and an anode flow path are provided in this order on a first surface of the electrolyte membrane, and a cathode catalyst layer and a cathode flow path are provided in this order on a second surface. The second fuel cell 31 also includes a pair of separators that sandwich the electrolyte membrane, the anode catalyst layer, the anode flow path, and the cathode catalyst layer and the cathode flow path. A second outlet flow path 32 is connected to the outlet of the anode flow path, and allows a seventh fluid (described later) to flow out of the anode flow path.

[0033] The electrolyte membrane, anode catalyst layer, anode flow path, cathode catalyst layer, cathode flow path, and separator constituting the second fuel cell 31 may be similar to the electrolyte membrane, anode catalyst layer, anode flow path, cathode catalyst layer, cathode flow path, and separator constituting the first fuel cell 11 provided in the first separation device 10, respectively. The second fuel cell 31 may be configured as a single fuel cell unit, or may be an assembly of a plurality of fuel cells (fuel cell stack).

[0034] The sealing means 33 (hereinafter also referred to as "first sealing means 33") serves to block the outflow of a fluid (a seventh fluid described below) from the anode flow channel of the second fuel cell 31. A sealing means 33 is provided in the second outlet channel 32 . The sealing means 33 may be, for example, a valve such as a solenoid valve or an electric valve.

[0035] The second separation device 30 may further include one or more of a second sealing means (not shown) that seals off the inflow of a fluid (third fluid) into the anode flow path of the second fuel cell 31, a third sealing means (not shown) that seals off the inflow of a fluid (fifth fluid described below) into the cathode flow path of the second fuel cell 31, and a fourth sealing means (not shown) that seals off the outflow of a fluid (eighth fluid described below) from the cathode flow path of the second fuel cell 31. The second sealing means is provided in a fourth hydrogen supply channel 124 (described later). The third sealing means is provided in a third oxygen supply channel 133 (described later). The fourth sealing means is provided in a second upstream supply channel 91B (described later).

[0036] <Water electrolysis device> The water electrolysis device 40 is provided upstream of the first separation device 10 and is a device that electrolyzes water. A known water electrolyzer can be used as the water electrolyzer 40, such as a solid polymer water electrolyzer, an alkaline water electrolyzer, etc. Among these, an alkaline water electrolyzer is preferred because it can generate a large amount of hydrogen gas.

[0037] <humidifier> The humidifier 50 is provided between the water electrolyzer 40 and the first separation device 10, and humidifies the fluids supplied to the first separation device 10 and the second separation device 30. Specifically, the humidifier 50 humidifies a fluid containing oxygen (hereinafter also referred to as a "fifth fluid") from the hydrogen and oxygen generated by electrolysis of water in the water electrolyzer 40. The fifth fluid humidified by the humidifier 50 is supplied to the cathode flow path of the first fuel cell 11 and the cathode flow path of the second fuel cell 31, respectively. The humidifier 50 is not particularly limited as long as it can generate water vapor.

[0038] <First Storage Container> The first storage container 60 is connected to the water electrolyzer 40 and is a tank for storing the raw material to be electrolyzed in the water electrolyzer 40 . The first storage container 60 has a raw material supply flow path 61. The raw material supply flow path 61 is a pipe for supplying raw materials to be electrolyzed from the first storage container 60 to the water electrolyzer 40. In other words, the first storage container 60 and the water electrolyzer 40 are connected by the raw material supply flow path 61. One end of the raw material supply flow path 61 is connected to the first storage container 60, and the other end is connected to the water electrolyzer 40. There are no particular limitations on the first storage container 60 as long as it can store the raw material. The raw material stored in the first storage container 60 may be water containing hydrogen isotopes.

[0039] <Second storage container> The second storage container 70 is a tank that stores the liquid (fourth fluid) discharged from the gas-liquid separator 20. There are no particular limitations on the second storage container 70 as long as it can store the fourth fluid.

[0040] <Third Storage Container> The third storage container 80 is a tank that stores the fluid (an eighth fluid, which will be described later) that flows out from the cathode flow channel of the second fuel cell 31. The third storage container 80 is not particularly limited as long as it can store the eighth fluid.

[0041] <Supply route> The supply path 90A is a pipe that supplies the liquid (fourth fluid) discharged from the gas-liquid separator 20 to the second storage container 70. That is, the gas-liquid separator 20 and the second storage container 70 are connected by the supply path 90A. One end of the supply path 90A is connected to the gas-liquid separator 20, and the other end is connected to the second storage container 70. A switching means 110A, which will be described later, is provided midway along the supply path 90A.

[0042] The supply path 90B is a pipe that supplies the fluid (eighth fluid) flowing out from the cathode flow path of the second fuel cell 31 to the third storage container 80. In other words, the second separation device 30 and the third storage container 80 are connected by the supply path 90B. One end of the supply path 90B is connected to the second fuel cell 31, and the other end is connected to the third storage container 80. A switching means 110B, which will be described later, is provided midway along the supply path 90B.

[0043] In the present invention, the supply path 90A that supplies the fourth fluid discharged from the gas-liquid separator 20 to the second storage container 70 is also particularly referred to as the "first supply path 90A." Also, the supply path 90B that supplies the eighth fluid flowing out from the cathode flow path of the second fuel cell 31 to the third storage container 80 is also particularly referred to as the "second supply path 90B." In addition, in the supply path 90A, the upstream side of the switching means 110A, i.e., the gas-liquid separator 20 side, is also referred to as the "first upstream supply path 91A," and the downstream side of the switching means 110A, i.e., the second storage container 70 side, is also referred to as the "first downstream supply path 92A." In addition, in the supply path 90B, the upstream side of the switching means 110B, i.e., the second separation device 30 side, is also referred to as the "second upstream supply path 91B," and the downstream side of the switching means 110B, i.e., the third storage container 80 side, is also referred to as the "second downstream supply path 92B."

[0044] <Return path> The return path 100A is a pipe that returns the liquid (fourth fluid) discharged from the gas-liquid separator 20 to the first storage container 60. One end of the return path 100A is connected to a switching means 110A (described later) that is provided midway along the supply path 90A, and the other end is connected to the first storage container 60. When the gas-liquid separator 20 and the return path 100A are connected by the switching means 110A, the gas-liquid separator 20 and the first storage container 60 are connected by the first upstream supply path 91A and the return path 100A.

[0045] The return flow path 100B is a pipe that returns the fluid (eighth fluid) flowing out from the cathode flow path of the second fuel cell 31 to the first storage container 60. One end of the return path 100B is connected to a switching means 110B (described later) that is provided midway along the supply path 90B, and the other end joins the return path 100A midway along the return path 100A. When the switching means 110B establishes a connected state in which the second separation device 30 and the return path 100B are connected, the second separation device 30 and the first storage container 60 are connected by the second upstream supply path 91B, the return path 100B, and the return path 100A.

[0046] In the present invention, the return path 100A, which returns the fourth fluid discharged from the gas-liquid separator 20 to the first storage container 60, is also particularly referred to as the "first return path 100A." Also, the return path 100B, which returns the eighth fluid flowing out from the cathode path of the second fuel cell 31 to the first storage container 60, is also particularly referred to as the "second return path 100B."

[0047] <Switching method> The switching means 110A is a means for switching between a connected state in which the gas-liquid separator 20 and the return path 100A are connected, and a non-connected state in which the connection state is released. The switching means 110A is provided in the supply path 90A. The switching means 110B is a means for switching between a connected state in which the second separation device 30 and the return path 100B are connected, and a non-connected state in which the connection state is released. The switching means 110B is provided in the supply path 90B.

[0048] Examples of the switching means 110A and 110B include valves such as electromagnetic valves and motor-operated valves. In the present invention, the switching means 110A that switches between a connection state in which the gas-liquid separator 20 and the reflux path 100A are connected (hereinafter also referred to as a "connection state A1") and a non-connection state in which the connection state A1 is released (hereinafter also referred to as a "non-connection state A2") is also referred to as a "first switching means 110A." Furthermore, the switching means 110B that switches between a connection state in which the second separation device 30 and the reflux path 100B are connected (hereinafter also referred to as a "connection state B1") and a non-connection state in which the connection state B1 is released (hereinafter also referred to as a "non-connection state B2") is also referred to as a "second switching means 110B."

[0049] <Hydrogen supply channel> The hydrogen supply flow path 120 is a pipe that connects the water electrolyzer 40, the humidifier 50, the first separator 10, the gas-liquid separator 20, and the second separator 30 in this order from the upstream side, and supplies a fluid containing hydrogen isotopes in this order. The hydrogen supply channel 120 includes a first hydrogen supply channel 121 , a second hydrogen supply channel 122 , a third hydrogen supply channel 123 , a fourth hydrogen supply channel 124 , and a first pump 125 .

[0050] The first hydrogen supply flow path 121 is a pipe for supplying a fluid (first fluid) containing hydrogen isotopes generated by electrolysis of water containing hydrogen isotopes in the water electrolyzer 40 from the water electrolyzer 40 to the humidifier 50. In other words, the water electrolyzer 40 and the humidifier 50 are connected by the first hydrogen supply flow path 121. The second hydrogen supply flow path 122 is a pipe for supplying the first fluid from the humidifier 50 to the first separation device 10. In other words, the humidifier 50 and the first separation device 10 are connected by the second hydrogen supply flow path 122. One end of the second hydrogen supply flow path 122 is connected to the humidifier 50, and the other end is connected to the inlet of the anode flow path of the first fuel cell 11. The third hydrogen supply flow path 123 is a pipe for supplying a fluid (second fluid) having a lower hydrogen isotope content than the first fluid from the first separation device 10 to the gas-liquid separator 20. In other words, the first separation device 10 and the gas-liquid separator 20 are connected by the third hydrogen supply flow path 123. One end of the third hydrogen supply flow path 123 is connected to the outlet of the anode flow path of the first fuel cell 11, and the other end is connected to the gas-liquid separator 20. The fourth hydrogen supply flow path 124 is a pipe for supplying the gas (third fluid) obtained by gas-liquid separation in the gas-liquid separator 20 from the gas-liquid separator 20 to the second separation device 30. In other words, the gas-liquid separator 20 and the second separation device 30 are connected by the fourth hydrogen supply flow path 124. One end of the fourth hydrogen supply flow path 124 is connected to the gas-liquid separator 20, and the other end is connected to the inlet of the anode flow path of the second fuel cell 31. The first pump 125 is provided in the first hydrogen supply passage 121 . In addition, since hydrogen is produced in the water electrolysis device 40, the pressure difference at that time causes the fluid to flow downstream. Therefore, it is not always necessary to provide the first pump 125, and the hydrogen supply flow path 120 does not necessarily have to have the first pump 125.

[0051] <Oxygen supply channel> The oxygen supply flow path 130 is a pipe that connects the water electrolyzer 40, the humidifier 50, and the first separator 10 or the second separator 30 in this order from the upstream side, and supplies an oxygen-containing fluid to these in this order. The oxygen supply channel 130 includes a first oxygen supply channel 131, a second oxygen supply channel 132, a third oxygen supply channel 133, and a second pump 134.

[0052] The first oxygen supply flow path 131 is a pipe for supplying a fluid (fifth fluid) containing oxygen generated by electrolysis of water containing hydrogen isotopes in the water electrolyzer 40 from the water electrolyzer 40 to the humidifier 50. In other words, the water electrolyzer 40 and the humidifier 50 are connected by the first oxygen supply flow path 131. The second oxygen supply flow path 132 is a pipe for supplying the fifth fluid from the humidifier 50 to the first separation device 10. That is, the humidifier 50 and the first separation device 10 are connected by the second oxygen supply flow path 132. One end of the second oxygen supply flow path 132 is connected to the humidifier 50, and the other end is connected to the inlet of the cathode flow path of the first fuel cell 11. The third oxygen supply flow path 133 is a pipe for supplying the fifth fluid from the humidifier 50 to the second separation device 30. That is, the humidifier 50 and the second separation device 30 are connected by the third oxygen supply flow path 133. One end of the third oxygen supply flow path 133 is connected to the humidifier 50, and the other end is connected to the inlet of the cathode flow path of the second fuel cell 31. The second pump 134 is provided in the first oxygen supply channel 131 . In addition, oxygen is generated in the water electrolysis device 40, and the resulting pressure difference causes the fluid to flow downstream. Therefore, it is not always necessary to provide the second pump 134, and the oxygen supply flow path 130 does not necessarily have to have the second pump 134.

[0053] <Control unit> The control unit 140 controls the operation of the first separation device 10, the gas-liquid separator 20, the second separation device 30, the sealing means 33, the water electrolysis device 40, the switching means 110A, 110B, the first pump 125, and the second pump 134. Specifically, when stopping the operation of the separation system 1, the control unit 140 switches the switching means 110A to a connection state A1 in which the gas-liquid separator 20 and the return path 100A are connected. In the connection state A1, it is preferable to switch the switching means 110B to a connection state B1 in which the second separation device 30 and the return path 100B are connected.

[0054] Furthermore, when the separation system 1 is operating, the control unit 140 uses the switching means 110A to set the connection state A1 between the gas-liquid separator 20 and the return path 100A to a disconnected state A2, and set the gas-liquid separator 20 to a connected state (hereinafter also referred to as a "connected state A3") between the second storage container 70 and the gas-liquid separator 20. At this time, it is preferable that the switching means 110B sets the connection state B1 between the second separation device 30 and the return path 100B to a disconnected state B2, and set the second separation device 30 to a connected state (hereinafter also referred to as a "connected state B3") between the third storage container 80 and the gas-liquid separator 20 to a connected state (hereinafter also referred to as a "connected state B1").

[0055] In addition, when stopping the operation of the separation system 1, the control unit 140 uses the switching means 110A to set the gas-liquid separator 20 and the return path 100A to a connection state A1, and then stops the first separation device 10 and operates the second separation device 30 so that the amount of power generated by the second separation device 30 is reduced.

[0056] In addition, when the control unit 140 stops the operation of the separation system 1, it closes the sealing means 33 and operates the second separation device 30 so that the anode side of the electrolyte membrane of the second separation device 30 is at a lower pressure than the cathode side. Furthermore, when stopping the operation of the separation system 1, the control unit 140 operates the second separation device 30 so that the amount of current during power generation is lower than the power generation state before the second separation device 30 was stopped. Furthermore, when stopping the operation of the separation system 1, the control unit 140 stops the second separation device 30 after the anode side of the second separation device 30 becomes lower in pressure than the cathode side.

[0057] In addition, when the separation system 1 is operating, the control unit 140 cools the second fluid supplied to the gas-liquid separator 20 using a cooling unit (not shown), and when the operation of the separation system 1 is stopped, the control unit 140 stops cooling the second fluid using the cooling unit after the first separation device 10 and the second separation device 30 have stopped.

[0058] <Separation system operation> An example of a separation method using the separation system 1 will be described below. First, water containing, for example, hydrogen isotopes is electrolyzed in a water electrolyzer 40. The fluid (first fluid) containing hydrogen isotopes obtained by this electrolysis is introduced into the inlet of the anode flow path of the first fuel cell 11 in the first separation device 10. At this time, the first fluid may be passed through a humidifier 50 before being introduced into the anode flow path of the first fuel cell 11, or may be introduced into the anode flow path of the first fuel cell 11 directly from the water electrolyzer 40. Note that even when the first fluid is passed through the humidifier 50, the first fluid is not humidified. In other words, the first fluid is simply passed through the humidifier 50 without being humidified. Separately, a fluid (fifth fluid) containing oxygen obtained by electrolysis is introduced into the cathode flow passage of the first fuel cell 11 of the first separation device 10 from the inlet. At this time, it is preferable to humidify the fifth fluid in a humidifier 50 before introducing it into the cathode flow passage of the first fuel cell 11. In this case, the fifth fluid contains oxygen and water vapor. The fifth fluid may also contain nitrogen.

[0059] In the first separation device 10, some of the hydrogen and hydrogen isotopes contained in the first fluid that has flowed into the anode flow path migrate from the anode flow path to the anode catalyst layer, and then from the anode catalyst layer through the electrolyte membrane to the cathode catalyst layer. The protons and hydrogen isotopes that have migrated to the cathode catalyst layer undergo an isotope exchange reaction with water vapor (HO) contained in the fifth fluid that has migrated from the cathode flow path to the cathode catalyst layer, in the cathode catalyst layer and at the interface between the electrolyte membrane and the cathode catalyst layer, to produce DO and HDO. The protons and hydrogen isotopes contained in the first fluid that do not migrate to the cathode catalyst layer are discharged from the outlet of the anode flow channel as a second fluid, which is a fluid having a lower hydrogen isotope content than the first fluid. The isotope exchange reaction also occurs on the surface of the anode catalyst layer.

[0060] The fifth fluid that passes through the cathode flow path of the first fuel cell 11 without being used in the above-mentioned isotope exchange reaction, and the D2O, HDO, and H2 that are produced by the isotope exchange reaction and move to the cathode flow path, are discharged as a fluid (hereinafter also referred to as the "sixth fluid") from the outlet of the cathode flow path of the first fuel cell 11. The sixth fluid flowing out from the cathode flow channel of the first fuel cell 11 may be separated into gas and liquid, or may be recovered as water containing D2O. When the sixth fluid is subjected to gas-liquid separation, the gas separated from the sixth fluid is discharged. The liquid separated from the sixth fluid may be supplied to the water electrolysis device 40 or may be recovered as water containing DO.

[0061] A part of the second fluid that flows out from the anode flow path of the first fuel cell 11 may be returned to the anode flow path of the first fuel cell 11, or the whole may be supplied to the gas-liquid separator 20 and used for power generation after being separated into gas and liquid in the gas-liquid separator 20. If the second fluid is used for power generation after being separated into gas and liquid, the protons and hydrogen isotopes contained in the second fluid can be consumed.

[0062] In the gas-liquid separator 20, the second fluid is separated into a gas (third fluid) and a liquid (fourth fluid). At this time, it is preferable that the control unit 140 operates a cooling unit (not shown) provided in the gas-liquid separator 20 to cool the second fluid supplied to the gas-liquid separator 20 by the cooling unit. Cooling the second fluid promotes gas-liquid separation of the second fluid. Furthermore, the control unit 140 causes the switching means 110A to switch the gas-liquid separator 20 and the return path 100A from the connected state A1 to a disconnected state A2, and to switch the gas-liquid separator 20 and the second storage container 70 to a connected state A3. The third fluid is supplied to the second separation device 30. Meanwhile, the fourth fluid is stored in the second storage vessel 70 as water containing D2O.

[0063] In the second separation device 30 , first, the third fluid supplied from the gas-liquid separator 20 flows into the inlet of the anode flow path of the second fuel cell 31 . Separately, a fifth fluid is introduced into the cathode flow passage of the second fuel cell 31 from the inlet. At this time, it is preferable to humidify the fifth fluid using a humidifier 50 before introducing the fifth fluid into the cathode flow passage of the second fuel cell 31. In this case, the fifth fluid contains oxygen and water vapor. The fifth fluid may also contain nitrogen.

[0064] A portion of the hydrogen and hydrogen isotopes contained in the third fluid that has flowed into the anode flow path of the second fuel cell 31 migrate in the form of ions from the anode flow path to the anode catalyst layer, and then from the anode catalyst layer through the electrolyte membrane to the cathode catalyst layer. The hydrogen ions and hydrogen isotope ions that have migrated to the cathode catalyst layer of the second fuel cell 31 react with oxygen that has migrated from the cathode flow path to the cathode catalyst layer in the cathode catalyst layer and at the interface between the electrolyte membrane and the cathode catalyst layer to produce water (HO and DO). This reaction generates electricity in the second separation device 30. In this way, the second fluid flowing out from the anode flow channel of the first fuel cell 11 is used for power generation after gas-liquid separation and is consumed.

[0065] The fluid (hereinafter also referred to as the "seventh fluid") that is not used for power generation and has a lower hydrogen isotope content than the third fluid is discharged from the outlet of the anode flow path of the second fuel cell 31. At this time, the sealing means 33 is left open by the control unit 140. The discharged seventh fluid may be discharged, or at least a portion of the seventh fluid may be returned to the anode flow path of the second fuel cell 31. Furthermore, the liquid generated on the anode side may be returned to the return flow path 100B.

[0066] Meanwhile, water (HO and DO) generated in the cathode catalyst layer of the second fuel cell 31 and transferred to the cathode flow path flows out as a fluid (hereinafter also referred to as an "eighth fluid") from the outlet of the cathode flow path of the second fuel cell 31. At this time, it is preferable that the control unit 140 controls the switching means 110B to switch the connection state B1 between the second separation device 30 and the return flow path 100B to a disconnected state B2, in which the connection state B1 is released, and to switch the connection state B3 between the second separation device 30 and the third storage container 80. By keeping the second separation device 30 and the third storage container 80 in the connected state B3, the water (HO and DO) that is the eighth fluid flowing out from the cathode flow path of the second fuel cell 31 can be stored in the third storage container 80 as water containing DO. In the present invention, the fluid discharged is appropriately treated after being discharged.

[0067] <How to stop the separation system> An example of a method for stopping the above-described separation system 1 will be described below with reference to FIG. FIG. 2 is a flowchart showing an example of the flow of a method for stopping the separation system 1.

[0068] First, it is determined whether or not a stop signal for the separation system 1 has been received (step S1). When the stop signal is received, the control unit 140 stops the water electrolyzer 40 (step S2). By stopping the water electrolyzer 40, the supply of the first fluid and the fifth fluid to the first separation device 10 and the supply of the fifth fluid to the second separation device 30 are stopped.

[0069] Next, the control unit 140 switches the switching means 110A to a disconnected state (hereinafter also referred to as "disconnected state A4") in which the connection state A3 between the gas-liquid separator 20 and the second storage container 70 is released, and the gas-liquid separator 20 is connected to the return path 100A in a connected state A1 (step S3). At this time, it is preferable that the control unit 140 causes the switching means 110B to switch the connection state B3 between the second separation device 30 and the third storage container 80 to a disconnected state (hereinafter also referred to as "disconnected state B4"), and switch the connection state B1 in which the second separation device 30 and the return path 100B are connected.

[0070] Next, the control unit 140 stops the first separation device 10 and operates the second separation device 30 so that the amount of power generated by the second separation device 30 decreases (step S4). At this time, it is preferable that the control unit 140 closes the sealing means 33 and operates the second separator 30 so that the anode side of the electrolyte membrane of the second separator 30 is at a lower pressure than the cathode side. It is also preferable that the control unit 140 operates the second separation device 30 so that the amount of current during power generation is lower than the power generation state before the second separation device 30 was stopped.

[0071] Next, the second separator 30 determines whether the pressure on the anode side (anode pressure) across the electrolyte membrane of the second fuel cell 31 is below a predetermined value (step S5). Specifically, it determines whether the pressure on the anode side across the electrolyte membrane of the second fuel cell 31 is lower than the pressure on the cathode side.

[0072] When the anode pressure falls below a predetermined value, the control unit 140 stops the second separation device 30 (step S6).

[0073] Next, the control unit 140 stops the cooling of the second fluid by the cooling unit (not shown) provided in the gas-liquid separator 20 (step S7). In the present invention, stopping the cooling of the second fluid by the cooling unit is also referred to as "stopping the gas-liquid separator 20." When the gas-liquid separator 20 is stopped, the separation system 1 is completely stopped.

[0074] <Action and effect> In the separation system and its shutdown method of this embodiment described above, when the separation system is shut down, after the water electrolysis device is shut down, the first switching means switches to connection state A1, in which the gas-liquid separator and the first return path are connected. By switching to connection state A1, when the separation system is shut down, the second fluid remaining in the first separation device, i.e., unreacted fluid or insufficiently separated fluid, can be separated into gas and liquid, and the liquid fourth fluid can be returned to the first storage container. At this stage, the second separation device is still operating, so the gaseous third fluid obtained by gas-liquid separation of the second fluid is used and consumed for power generation in the second decomposition device. Therefore, the separation system can be shut down without the unreacted fluid or insufficiently separated fluid leaking to the outside. Furthermore, because the unreacted fluid or insufficiently separated fluid is no longer supplied to the second storage container, the quality of the separated fluid obtained during operation of the separation system, i.e., the fourth fluid stored in the second storage container, can be maintained. Furthermore, when the separation system is shut down, if the second switching means is set to a connection state B1 in which the second separator and the second return path are connected after the water electrolysis device is shut down, even if the separation performance deteriorates due to a decrease in generated current, the eighth fluid generated on the cathode side can be returned to the first storage container, allowing the system to be shut down. Also, the quality of the eighth fluid stored in the third storage container can be maintained.

[0075] Furthermore, when the separation system is shut down, the first separation device is shut down and the second separation device is operated so that the amount of power generated by the second separation device is reduced, thereby reducing the residual pressure in the separation system and shutting down the separation system. Furthermore, in the second separation device, the fluid (third fluid) containing hydrogen isotopes can be prevented from leaking from the anode side through the cathode side to the outside. In this case, if the second separator is operated so that the anode side of the second fuel cell has a lower pressure than the cathode side across the electrolyte membrane, the third fluid can be further prevented from leaking from the anode side to the cathode side. Also, if the second separator is operated so that the amount of current during power generation is lower than the state before the second separator was stopped, deterioration of the electrolyte membrane of the second separator can be suppressed.

[0076] Furthermore, when the separation system is stopped, if the second separation device is stopped after the anode side of the second separation device becomes lower in pressure than the cathode side, the second separation device can be stopped after the third fluid has been sufficiently consumed in the second separation device.

[0077] If water vapor remains in the fluid in the piping of each separation device, a drop in temperature during shutdown of the separation system can cause condensation, resulting in the freezing of the piping. When the separation system is shut down, if the cooling of the second fluid by the cooling unit of the gas-liquid separator is stopped after the first and second separation devices are shut down, the second fluid is supplied to the gas-liquid separator and separated into gas and liquid while the second separation device is operating during shutdown of the separation system. This reduces the likelihood of fluid remaining in the piping of the first separation device, and gas is removed from the fluid supplied to the second separation device, preventing freezing within the piping. Furthermore, even if the fluid remaining in the piping of each separation device contains HDO, the gas-liquid separator cools the fluid, condensing and separating the HDO, thereby maintaining the separation function during shutdown of the separation system.

[0078] <Other embodiments> The separation system and its activation method of the present invention are not limited to those described above. 1, the second separation device 30 includes a sealing means 33 that seals the outflow of the fluid (seventh fluid) from the anode flow path of the second fuel cell 31, but the first separation device 10 may include a sealing means (hereinafter also referred to as a "fifth sealing means") that seals the outflow of the fluid (second fluid) from the anode flow path of the first fuel cell 11. Furthermore, the first separation device 10 may further include one or more of a sixth sealing means that seals the inflow of the fluid (first fluid) into the anode flow path of the first fuel cell 11, a seventh sealing means that seals the inflow of the fluid (fifth fluid) into the cathode flow path of the first fuel cell 11, and an eighth sealing means that seals the outflow of the fluid (sixth fluid) from the cathode flow path of the first fuel cell 11.

[0079] In addition, in the separation system 1 shown in Figure 1, the other end of the return path 100B joins the return path 100A midway along the return path 100A, but the return path 100B may also be connected directly to the first storage container 60.

[0080] Furthermore, during operation of the separation system 1, the oxygen-containing fluid (fifth fluid) obtained in the water electrolyzer 40 may be supplied directly from the water electrolyzer 40 to the second separation device 30.

[0081] Furthermore, although the separation system 1 shown in FIG. 1 includes two separation devices, the separation system 1 may include three or more separation devices. In this case, as long as at least the most upstream separation device among the three or more separation devices is the first separation device 10 and the most downstream separation device is the second separation device 30, the remaining separation devices may be the first separation device 10 or the second separation device 30. In particular, it is more preferable that only the most downstream separation device is provided with the second separation device 30. Furthermore, when two or more first separation devices 10 are provided, a gas-liquid separator 20 may be provided between each of the first separation devices 10, or the first separation devices 10 may be connected to each other and a gas-liquid separator 20 may be provided between the first separation device 10 and the second separation device 30 located at the rearmost position. [Explanation of symbols]

[0082] 1 Separation System 10 First Separation Device 11 First Fuel Cell 12 First Outlet Channel 20 Gas-liquid separator 30 Second Separator 31 Second Fuel Cell 32 Second Outlet Channel 33 Sealing means (first sealing means) 40 Water Electrolyzer 50 humidifier 60 First Storage Container 61 raw material supply channel 70 Second Storage Container 80 Third Storage Container 90A supply line (first supply line) 90B Supply Channel (Second Supply Channel) 91A First upstream supply channel 92A First downstream supply channel 91B Second upstream supply channel 92B Second downstream supply channel 100A return path (first return path) 100B Reflux channel (second reflux channel) 110A Switching means (first switching means) 110B Switching means (second switching means) 120 Hydrogen supply channel 121 first hydrogen supply channel 122 second hydrogen supply channel 123 Third hydrogen supply channel 124 Fourth hydrogen supply channel 125 First Pump 130 oxygen supply channel 131 First oxygen supply channel 132 Second oxygen supply channel 133 Third oxygen supply channel 134 Second Pump 140 Control Unit

Claims

1. 1. A separation system for separating hydrogen isotopes from a fluid containing said hydrogen isotopes, comprising: The separation system includes a first separation device into which a first fluid containing hydrogen and the hydrogen isotopes is introduced and which outputs a second fluid having a lower hydrogen isotope content than the first fluid; a gas-liquid separator provided downstream of the first separation device, which separates the second fluid flowing out of the first separation device into a third fluid that is a gas and a fourth fluid that is a liquid; a second separation device provided downstream of the gas-liquid separator and configured to generate power using the third fluid discharged from the gas-liquid separator; a water electrolysis device that is provided upstream of the first separation device and that electrolyzes water; an oxygen supply passage that supplies a fifth fluid containing oxygen generated by the water electrolysis device to the first separation device and the second separation device; a first storage container connected to the water electrolysis device and configured to store a raw material to be electrolyzed in the water electrolysis device; a return path for returning the fourth fluid discharged from the gas-liquid separator to the first storage container; a switching means for switching between a connected state in which the gas-liquid separator and the return path are connected and a disconnected state in which the connection state is released; a control unit, the first separation device comprises a first fuel cell; the second separation device comprises a second fuel cell; In the first fuel cell, a part of the hydrogen and hydrogen isotopes contained in the first fluid undergoes an isotope exchange reaction with water vapor contained in the humidified fifth fluid that has separately flowed into the first fuel cell to produce D ２ O and HDO are produced, and the remainder flows out of the first fuel cell as the second fluid and is separated into gas and liquid in the gas-liquid separator; The D produced by the first fuel cell ２ a sixth fluid comprising O and the HDO exits the first fuel cell; In the second fuel cell, the protons and a part of the hydrogen isotopes contained in the third fluid react in an ionic state with oxygen contained in the fifth fluid separately flowing into the second fuel cell to produce H ２ O and D ２ O is produced, and the remainder exits the second fuel cell as a seventh fluid having a lower hydrogen isotope content than the third fluid; The H produced by the second fuel cell ２ O and the above D ２ an eighth fluid comprising O exits the second fuel cell; The control unit causes the switching unit to switch to the connected state when the operation of the separation system is stopped.

2. a second storage vessel for storing the fourth fluid discharged from the gas-liquid separator; a supply path that supplies the fourth fluid discharged from the gas-liquid separator to the second storage container, The switching means is provided in the supply path, The separation system according to claim 1 , wherein the control unit causes the switching means to set the separation system to the disconnected state and the gas-liquid separator and the second storage container to the connected state when the separation system is operating.

3. 2. The separation system according to claim 1, wherein, when stopping operation of the separation system, the control unit stops the first separation device after switching the switching means to the connected state, and operates the second separation device so as to reduce the amount of power generated by the second separation device.

4. the first fuel cell and the second fuel cell each include an electrolyte membrane, and an anode catalyst layer and an anode flow channel are provided in this order on a first surface of the electrolyte membrane, and a cathode catalyst layer and a cathode flow channel are provided in this order on a second surface of the electrolyte membrane; at least one of the first separation device and the second separation device includes a sealing means for sealing off fluid from flowing out of the anode flow path; 4. The separation system according to claim 3, wherein when the control unit stops operation of the separation system, the control unit closes the sealing means and operates the second separation device so that the anode side of the electrolyte membrane of the second fuel cell is at a lower pressure than the cathode side.

5. The separation system according to claim 4, wherein, when the control unit stops operation of the separation system, the control unit operates the second separation device so that the amount of current generated is lower than the amount of current generated before the second separation device was stopped.

6. The separation system according to claim 4 or 5, wherein when the control unit stops operation of the separation system, the control unit stops the second separation device after the anode side of the second fuel cell becomes lower in pressure than the cathode side.

7. the gas-liquid separator includes a cooling unit that cools the second fluid supplied to the gas-liquid separator, The separation system described in claim 6, wherein the control unit cools the second fluid supplied to the gas-liquid separator by the cooling unit when the separation system is operating, and when the operation of the separation system is stopped, the control unit stops cooling the second fluid by the cooling unit after the first separation device and the second separation device have stopped.

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