Equipment for manufacturing synthetic compounds and method for protecting catalysts

Abstract

This disclosure aims to provide a synthetic compound manufacturing facility and a catalyst protection method that reduce the consumption of inert gas compared to the case where inert gas is used when shutting down water electrolysis equipment and reaction equipment. [Solution] The methanation equipment 100 includes a water electrolysis equipment 110 that obtains hydrogen by electrolyzing water, and a Sabatier reaction equipment 120 that obtains methane by reacting the hydrogen obtained from the water electrolysis equipment 110 with carbon dioxide. When the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are shut down, the internal gas is replaced with carbon dioxide.

Description

Technical Field

[0001] The present disclosure relates to synthetic compound manufacturing equipment and a catalyst protection method.

Background Art

[0002] For example, Patent Document 1 discloses a hydrocarbon production system that produces hydrocarbons having two or more carbon atoms from methane by an oxidative coupling reaction of methane, the system including an oxidative coupling reaction apparatus that performs an oxidative coupling reaction from methane and oxygen, a raw material gas separation apparatus that separates the inert component from a raw material gas containing an inert component, a carbon dioxide separation apparatus that separates carbon dioxide contained in the product gas generated by the oxidative coupling reaction apparatus, and a methanation apparatus that performs a methanation reaction from hydrogen and carbon dioxide.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In synthetic compound manufacturing equipment, when stopping the operation of the water electrolysis equipment, it is required to protect the catalysts possessed by the water electrolysis equipment and the reaction equipment. However, in the technology described in Patent Document 1, when stopping the operation of the water electrolysis equipment and the reaction equipment, the internal gas is replaced with an inert gas, so the consumption of the inert gas tends to increase when the operation is stopped.

[0005] An object of the present disclosure is to provide a synthetic compound manufacturing equipment and a catalyst protection method in which the consumption of an inert gas is reduced as compared with the case of using an inert gas when stopping the operation of the water electrolysis equipment and the reaction equipment.

Means for Solving the Problems

[0006] The first embodiment of the synthetic compound manufacturing equipment comprises a water electrolysis unit that obtains hydrogen by electrolyzing water, and a reaction unit that obtains a synthetic compound by reacting the hydrogen obtained from the water electrolysis unit with carbon dioxide, wherein the internal gas of the water electrolysis unit and the reaction unit is replaced with carbon dioxide when they are shut down.

[0007] In the synthetic compound manufacturing equipment of this embodiment, the internal gas of the water electrolysis equipment and reaction equipment is replaced with carbon dioxide when the equipment is shut down. Therefore, with this synthetic compound manufacturing equipment, the amount of inert gas consumed is reduced compared to when an inert gas is used when the water electrolysis equipment and reaction equipment are shut down.

[0008] The synthetic compound manufacturing equipment of the second embodiment is the same as the synthetic compound manufacturing equipment of the first embodiment, wherein when the water electrolysis equipment is shut down, the internal gas is replaced with carbon dioxide, and when the reaction equipment is shut down, the replacement operation is started after the internal gas of the water electrolysis equipment has been replaced with carbon dioxide, and the internal gas of the reaction equipment is replaced with carbon dioxide until the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration, and the replacement operation is terminated when the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration.

[0009] In this embodiment of the synthetic compound manufacturing apparatus, the internal gas of the water electrolysis equipment is replaced with carbon dioxide, and then the reaction equipment is replaced with carbon dioxide until the internal hydrogen gas concentration reaches a predetermined concentration. As a result, in this synthetic compound manufacturing apparatus, the internal gas of the water electrolysis equipment is replaced with carbon dioxide, and then the internal hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration.

[0010] Therefore, with this synthetic compound manufacturing equipment, compared to the case where the internal gas of the water electrolysis equipment and the reaction equipment are replaced with carbon dioxide at the same time, the situation in which the internal gas of the water electrolysis equipment is not replaced with carbon dioxide and the synthetic compound manufacturing equipment shuts down is less likely to occur.

[0011] The synthetic compound manufacturing equipment of the third embodiment is the same as the synthetic compound manufacturing equipment of the first embodiment, wherein when the reaction equipment is shut down, the internal gas is replaced with carbon dioxide until the internal hydrogen gas concentration reaches a predetermined concentration, and when the water electrolysis equipment is shut down, the replacement operation is started after the internal hydrogen gas concentration inside the reaction equipment has been replaced with carbon dioxide until a predetermined concentration has been reached, and the replacement operation is completed when the internal gas is replaced with carbon dioxide.

[0012] In this embodiment of the synthetic compound manufacturing equipment, the hydrogen gas concentration inside the reaction equipment is replaced with carbon dioxide until it reaches a predetermined concentration, and only then is the internal gas of the water electrolysis equipment replaced with carbon dioxide. Therefore, with this synthetic compound manufacturing equipment, compared to the case where the internal gases of the water electrolysis equipment and the reaction equipment are replaced with carbon dioxide at the same time, the situation in which the operation of the synthetic compound manufacturing equipment stops due to the internal gas of the water electrolysis equipment not being replaced with carbon dioxide is less likely to occur.

[0013] The synthetic compound manufacturing equipment of the fourth embodiment is, in addition to the synthetic compound manufacturing equipment described in the first embodiment, The reaction equipment is supplied with a gas whose hydrogen gas concentration has been adjusted to a predetermined concentration using carbon dioxide during the operation of the water electrolysis equipment, thereby replacing the internal gas of the reaction equipment.

[0014] In the synthetic compound manufacturing equipment of this embodiment, the reaction equipment's internal gas is replaced with a gas whose hydrogen gas concentration has been adjusted to a predetermined concentration by carbon dioxide supplied during the operation of the water electrolysis equipment. In other words, when the reaction equipment is shut down, its internal gas is replaced with a pre-adjusted gas. Therefore, this synthetic compound manufacturing equipment makes it easier to prevent the operation of the synthetic compound manufacturing equipment from being shut down while there is variation in the hydrogen gas concentration of the internal gas of the reaction equipment.

[0015] The synthetic compound manufacturing apparatus of the fifth embodiment is the same as the synthetic compound manufacturing apparatus of the first embodiment, wherein the water electrolysis equipment and the reaction equipment are shut down at the same time when the internal gas is replaced with carbon dioxide.

[0016] In the synthetic compound manufacturing facility of this embodiment, the water electrolysis equipment and the reaction equipment are shut down simultaneously after their internal gases are replaced with carbon dioxide. As a result, the time required to replace the internal gases of the water electrolysis equipment and the reaction equipment with carbon dioxide is shortened. Therefore, this synthetic compound manufacturing facility can reduce the amount of carbon dioxide used compared to a system where the internal gases of the water electrolysis equipment and the reaction equipment are replaced with carbon dioxide at different times.

[0017] The catalyst protection method of the sixth embodiment is a synthetic compound manufacturing facility having a water electrolysis facility that obtains hydrogen by electrolyzing water, and a reaction facility that obtains a synthetic compound by reacting hydrogen obtained from the water electrolysis facility with carbon dioxide, wherein the catalyst is protected without supplying an inert gas when the water electrolysis facility is shut down.

[0018] In the catalyst protection method of this embodiment, the water electrolysis equipment and the reaction equipment are not supplied with inert gas when the water electrolysis equipment is shut down. Therefore, this catalyst protection method reduces the amount of inert gas consumed when the water electrolysis equipment and the reaction equipment are shut down compared to when inert gas is used. [Effects of the Invention]

[0019] According to this disclosure, a synthetic compound manufacturing facility and a catalyst protection method are provided that reduce the consumption of inert gas compared to when an inert gas is used when shutting down a water electrolysis facility and a reaction facility. [Brief explanation of the drawing]

[0020] [Figure 1] This is a diagram showing a methanation system according to the present invention. [Figure 2] This is a diagram illustrating the control system of a methanation facility. [Figure 3] This diagram illustrates the procedure for stopping the methanation equipment according to the first embodiment. [Figure 4] This diagram illustrates the procedure for stopping the methanation equipment according to the second embodiment. [Figure 5] It is a diagram for explaining the procedure for stopping the methanation facility according to the third embodiment. [Figure 6] It is a diagram for explaining the procedure for stopping the methanation facility according to the fourth embodiment.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the drawings. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0022] (Configuration) (Methanation Facility 100) FIG. 1 shows a methanation facility 100 according to an embodiment of the present disclosure. The methanation facility 100 includes a water electrolysis facility 110, a Sabatier reaction facility 120, and a control device 32. Further, as shown in FIG. 1, the methanation facility includes a pure water supply unit 180 and a carbon dioxide supply unit 190. The methanation facility 100 is an example of the "synthetic compound production facility" in the present disclosure. The Sabatier reaction facility 120 is an example of the "reaction facility" in the present disclosure.

[0023] (Water Electrolysis Facility 110) The water electrolysis facility 110 has a so-called water electrolysis cell stack. The water electrolysis cell stack included in the water electrolysis facility 110 is formed by stacking water electrolysis cells that form an anode and a cathode with an electrolyte membrane interposed therebetween. In the water electrolysis facility 110, due to the application of electric current by the water electrolysis cell stack, the water supplied to the anode is electrolyzed, oxygen is generated at the anode, and hydrogen is generated at the cathode. Further, the water electrolysis facility 110 is connected to a control device 32 and a power supply device (not shown), etc., and the amount of electric current applied is controlled by the control device, and the amount of water electrolysis is controlled.

[0024] A pure water supply line 148 is connected to the anode inlet of the water electrolysis equipment 110, and water is supplied from the pure water supply line 148. A carbon dioxide supply line 160 is connected to the cathode inlet of the water electrolysis equipment 110, and carbon dioxide is supplied from the carbon dioxide supply line 160. A hydrogen delivery line 152 is connected to the cathode outlet of the water electrolysis equipment 110, and hydrogen is delivered from the hydrogen delivery line 152. One end of a water-oxygen delivery line 150 is connected to the anode outlet of the water electrolysis equipment 110, and oxygen and undecomposed water are delivered from the water-oxygen delivery line 150.

[0025] The other end of the hydrogen delivery line 152 is connected to the first intermediate connection line 154 via the first valve 132.

[0026] The water-oxygen delivery line 150 delivers oxygen to the outside of the water electrolysis equipment 110. The other end of the water-oxygen delivery line 150 may be connected to any equipment, and as shown in Figure 1, it may not be connected to any other equipment. In other words, the water and oxygen may be released. The water and oxygen delivered from the water-oxygen delivery line 150 may be used for any purpose. Alternatively, the oxygen and water may be separated from the water-oxygen delivery line 150, and the water separated from the oxygen may be supplied to the pure water supply unit 180.

[0027] As shown in Figure 1, the pure water supply unit 180 is connected to the pure water supply line 148 and supplies pure water to the water electrolysis equipment 110 through the pure water supply line 148.

[0028] As shown in Figure 1, the carbon dioxide supply unit 190 is connected to the carbon dioxide supply line 160. The carbon dioxide supply line 160 branches off midway through its flow path and is connected to the cathode-side inlet of the water electrolysis equipment 110 and the second intermediate connection line 158. In other words, the carbon dioxide supply unit 190 supplies carbon dioxide to the water electrolysis equipment 110 and the second intermediate connection line 158 through the carbon dioxide supply line 160. The carbon dioxide supply line 160 is also equipped with a seventh valve 144, and the supply of carbon dioxide to the water electrolysis equipment 110 can be controlled by opening and closing the seventh valve 144.

[0029] Furthermore, as shown in Figure 1, the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are connected via the hydrogen delivery line 152, the first intermediate connection line 154, the second intermediate connection line 158, and the hydrogen-carbon dioxide mixing line 162 in that order.

[0030] As mentioned above, the first intermediate connection line 154 is connected to the hydrogen delivery line 152 via the first valve 132. Furthermore, as shown in Figure 1, the first intermediate connection line 154 is connected to the hydrogen emission line 156 via the second valve 134. The first intermediate connection line 154 and the second intermediate connection line 158 are connected via the third valve 136.

[0031] As shown in Figure 1, the hydrogen emission line 156 is not connected to any other equipment at its other end, and hydrogen is emitted from it. Alternatively, the hydrogen emission line 156 may be connected to other equipment to supply hydrogen to that equipment.

[0032] As mentioned above, the second intermediate connection line 158 is connected to the carbon dioxide supply line 160 via the fourth valve 138 and to the hydrogen-carbon dioxide mixing line 162 via the fifth valve 140. In other words, hydrogen flows into the second intermediate connection line 158 from the side of the third valve 136 and carbon dioxide flows in from the side of the fourth valve 138. The hydrogen and carbon dioxide can then be mixed in the internal gas of the second intermediate connection line 158. The mixed hydrogen and carbon dioxide then flow into the hydrogen-carbon dioxide mixing line 162.

[0033] (Sabatier Reaction Plant 120) The Sabatier reaction apparatus 120 produces methane and water as synthetic compounds through the Sabatier reaction between hydrogen and carbon dioxide. The Sabatier reaction apparatus 120 is also connected to a control device 32 and a temperature control device (not shown). The temperature of the Sabatier reaction apparatus 120 is controlled by the temperature control device, and the Sabatier reaction is controlled accordingly. Specifically, when starting the Sabatier reaction in the Sabatier reaction apparatus 120, the control device 32 raises the temperature of the Sabatier reaction apparatus 120 using the temperature control device. When stopping the Sabatier reaction in the Sabatier reaction apparatus 120, the control device 32 lowers the temperature of the Sabatier reaction apparatus 120 using the temperature control device. As an example, the temperature control device includes a heat transfer fluid circulation device for raising the temperature and a chiller (refrigerant circulation device) for lowering the temperature. Of the methane and water produced in the Sabatier reaction plant 120, the methane is sent to the methane delivery line 164. The water produced by the Sabatier reaction is separated by a water separator (not shown) and discharged from the Sabatier reaction plant 120.

[0034] A hydrogen gas concentration meter 170 is provided in the methane delivery line 164, and the hydrogen concentration in the methane delivery line 164 is measured in a timely manner. The methane delivery line 164 is connected to the methane supply unit 166 via the sixth valve 142. The methane delivered to the methane supply unit 166 may be used for any purpose.

[0035] (Control device 32) The control device 32 is a device that controls the methanation equipment 100. Figure 2 shows a block diagram illustrating the hardware configuration of the control device 32 in this embodiment. As shown in Figure 2, the control device 32 comprises a control unit 40 and a valve control unit 50. These components are connected to each other via an input / output interface (I / O) 45.

[0036] The control unit 40 is a device that controls each part of the control device 32. This control unit 40 has computer-like functionality and, as shown in Figure 2, includes a CPU 41 (Central Processing Unit), RAM 42 (Random Access Memory), and ROM 43 (Read Only Memory). The CPU 41, RAM 42, and ROM 43 are each interconnected by a control bus 44.

[0037] The CPU 41 is a central processing unit that executes various programs, including program 46, to operate the methanation equipment 100 and controls its various components. The ROM 43 stores various programs, including program 46, and various data. The RAM 42 temporarily stores program 46 or data as a working area.

[0038] In the control unit 40, the CPU 41 reads various programs, including program 46, from the ROM 43 and executes program 46 using RAM 42 as a work area. By executing program 46, the CPU 41 realizes various functions that control each part of the control device 32.

[0039] The valve control unit 50 is a component that controls a total of seven valves, from the first valve 132 to the seventh valve 144, according to instructions from the CPU 41. More specifically, it drives the seven valves, from the first valve 132 to the seventh valve 144, to switch between an open state and a closed state, according to instructions from the CPU 41.

[0040] In this embodiment, the CPU 41 executes a normal operation mode and an operation stop mode by executing a program 46.

[0041] In normal operation mode, as described above, the CPU 41 produces hydrogen and oxygen by electrolyzing pure water in the water electrolysis equipment 110, and sends the hydrogen to the Sabatier reaction equipment 120. The CPU 41 also controls the temperature of the Sabatier reaction equipment 120 to generate methane gas from hydrogen and carbon dioxide through the Sabatier reaction.

[0042] Furthermore, in the shutdown mode, the CPU 41 performs a series of operations, as described later, to stop the reactions in the water electrolysis equipment 110 and the Sabatier reaction equipment 120, and to stop the production of methane gas by the methanation equipment 100.

[0043] Incidentally, in order to maintain reaction efficiency over the long term, measures are needed to prevent catalyst degradation during shutdowns of the water electrolysis cell stack in the water electrolysis equipment 110. Specifically, in the case of water electrolysis cell stacks, oxidation and dissolution of the electrode catalyst are avoided by suppressing rapid potential changes and maintaining an inert gas atmosphere such as nitrogen gas. Similarly, in the Sabatier reaction equipment 120, it is necessary to maintain an inert gas atmosphere such as nitrogen gas during shutdowns to prevent the adhesion of unwanted by-reaction products to the catalyst surface.

[0044] Next, an embodiment of the procedure for shutting down the methanation equipment 100 of this disclosure will be described. More specifically, a method for protecting the catalyst without supplying an inert gas when shutting down the water electrolysis equipment 110 in the methanation equipment 100 will be described. In this specification, "shutting down" refers to the period from the start of a series of operations, including stopping the power supply to the water electrolysis equipment 110 and the Sabatier reaction equipment 120, lowering the reaction temperature, and adjusting the gas supply conditions, in order to terminate the operation of the methanation equipment 100, including the water electrolysis equipment 110 and the Sabatier reaction equipment 120, until the reaction in the water electrolysis equipment 110 and the Sabatier reaction equipment 120 is completed and the replacement of the internal gas is completed. In other words, "shutting down" refers to the period during which the CPU 41 transitions from normal operation mode to shutdown mode and performs the operation to shut down the methanation equipment 100.

[0045] (Catalyst protection method) As a catalyst protection method in this disclosure, the control device 32 protects the catalyst by performing one of the procedures in each of the embodiments shown below as the operation stop mode. In this specification, "replacement work" refers to a series of operations performed continuously until the gas present inside the water electrolysis equipment 110 or the Sabatier reaction equipment 120 is replaced with carbon dioxide until the internal gas concentration reaches a predetermined target value. In each embodiment, immediately before stopping the operation of the methanation equipment 100 (in other words, during operation), the first valve 132, third valve 136, fourth valve 138, fifth valve 140, and sixth valve 142 are open, and the second valve 134 and seventh valve 144 are closed.

[0046] [First Embodiment] As shown in Figure 3, in this embodiment, first, as step S102, the CPU 41 stops the reaction in the Sabatier reaction apparatus 120. Specifically, the CPU 41 stops the Sabatier reaction by cooling the Sabatier reaction apparatus 120 while continuing to operate the water electrolysis apparatus 110. After confirming that the Sabatier reaction apparatus 120 has cooled and the Sabatier reaction has stopped, the CPU 41 stops the power supply to the water electrolysis apparatus 110 and closes the fifth valve 140 to stop the gas supply to the Sabatier reaction apparatus 120.

[0047] Next, in step S104, the CPU 41 supplies only carbon dioxide to the water electrolysis equipment 110. Specifically, the CPU 41 supplies carbon dioxide to the cathode-side inlet of the water electrolysis equipment 110 by opening the second valve 134 and the seventh valve 144. As a result, the internal gas of the water electrolysis equipment 110 is replaced with carbon dioxide.

[0048] Next, in step S106, the CPU 41 replaces the internal gas in the second intermediate connection line 158, the internal gas in the first intermediate connection line 154, and the internal gas in the hydrogen delivery line 152 with carbon dioxide. Specifically, the CPU 41 keeps the second valve 134 open while the fifth valve 140 is closed. As a result, the internal gas in the second intermediate connection line 158, the internal gas in the first intermediate connection line 154, and the internal gas in the hydrogen delivery line 152 are replaced with carbon dioxide and released from the hydrogen release line 156.

[0049] Next, in step S108, CPU 41 supplies only carbon dioxide to the Sabatier reaction plant 120. Specifically, after the internal gas of the water electrolysis plant 110 has been sufficiently replaced with carbon dioxide, CPU 41 closes the second valve 134 and opens the fifth valve 140. This replaces the internal gas of the Sabatier reaction plant 120 with carbon dioxide.

[0050] Next, in step S110, the CPU 41 seals the water electrolysis equipment 110 and the Sabatier reaction equipment 120 to maintain the concentration of the internal gas. That is, the CPU 41 confirms that the hydrogen concentration in the Sabatier reaction equipment 120, more specifically the hydrogen concentration in the methane delivery line 164, has reached a predetermined target concentration, and then stops the supply of carbon dioxide from the carbon dioxide supply unit 190.

[0051] Specifically, CPU 41 stops carbon dioxide from flowing into the water electrolysis equipment 110 by closing the seventh valve 144. CPU 41 also stops carbon dioxide from flowing from the water electrolysis equipment 110 to the hydrogen delivery line 152 by closing the first valve 132. This seals the internal gas of the water electrolysis equipment 110, maintaining the concentration of the internal gas (specifically, the hydrogen gas concentration). Furthermore, CPU 41 stops carbon dioxide from flowing into the Sabatier reaction equipment 120 and the second intermediate connection line 158 by closing the fourth valve 138. Additionally, CPU 41 seals the internal gas of the Sabatier reaction equipment 120 by closing the fifth valve 140 and the sixth valve 142, maintaining the concentration of the internal gas (specifically, the hydrogen gas concentration) of the Sabatier reaction equipment 120.

[0052] Thus, in the methanation equipment 100 of this embodiment, the internal gas of the water electrolysis equipment 110 and the Sabatier reaction equipment 120 is replaced with carbon dioxide when they are shut down. Therefore, with this methanation equipment 100, the consumption of inert gas is reduced compared to when an inert gas is used when the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are shut down. In other words, with this methanation equipment 100, there is no need to provide a supply facility for supplying inert gas.

[0053] Furthermore, in this methanation equipment 100 of this embodiment, the internal gas of the water electrolysis equipment 110 is replaced with carbon dioxide, and then the hydrogen gas concentration inside the Sabatier reaction equipment 120 is replaced with carbon dioxide until it reaches a predetermined concentration. As a result, in this methanation equipment 100, the hydrogen gas concentration inside the Sabatier reaction equipment 120 reaches a predetermined concentration after the internal gas of the water electrolysis equipment 110 has been replaced with carbon dioxide.

[0054] Therefore, with this methanation equipment 100, compared to the case where the internal gas of the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are replaced with carbon dioxide at the same time, the situation in which the internal gas of the water electrolysis equipment 110 is not replaced with carbon dioxide and the methanation equipment 100 stops operating is less likely to occur.

[0055] [Second Embodiment] As shown in Figure 4, in this embodiment, first, as step S202, the CPU 41 stops the reaction in the Sabatier reaction apparatus 120. Specifically, the CPU 41 stops the Sabatier reaction by cooling the Sabatier reaction apparatus 120 while continuing to operate the water electrolysis apparatus 110. After confirming that the Sabatier reaction apparatus 120 has cooled and the Sabatier reaction has stopped, the CPU 41 stops the electrolysis of water by cutting off the power supply to the water electrolysis apparatus 110, and also closes the fifth valve 140 to stop the gas supply to the Sabatier reaction apparatus 120.

[0056] Next, in step S204, CPU 41 supplies only carbon dioxide to the Sabatier reactor 120. Specifically, CPU 41 supplies only carbon dioxide to the Sabatier reactor 120 by opening the fifth valve 140 and closing the third valve 136. As a result, the internal gas of the Sabatier reactor 120 is replaced with carbon dioxide.

[0057] Then, in step S206, the CPU 41 seals the Sabatier reactor 120 to maintain the concentration of the internal gas. Specifically, the CPU 41 confirms that the hydrogen concentration inside the Sabatier reactor 120, i.e., the hydrogen concentration in the methane delivery line 164, has reached a predetermined target concentration, and stops the supply of carbon dioxide to the Sabatier reactor 120. Then, by closing the sixth valve 142, the CPU 41 seals the internal gas of the Sabatier reactor 120 and maintains the concentration of the internal gas (specifically, the hydrogen gas concentration) inside the Sabatier reactor 120.

[0058] Next, in step S208, the CPU 41 replaces the internal gas of the water electrolysis equipment 110, the second intermediate connection line 158, and the first intermediate connection line 154 with carbon dioxide. Specifically, the CPU 41 supplies carbon dioxide to the water electrolysis equipment 110 by opening the seventh valve 144. In addition, by closing the fifth valve 140 and opening the second valve 134, the internal gas of the water electrolysis equipment 110 is replaced with carbon dioxide. The internal gas in the second intermediate connection line 158, the first intermediate connection line 154, and the hydrogen delivery line 152 is replaced with carbon dioxide and released from the hydrogen release line 156.

[0059] Next, in step S210, the CPU 41 seals the water electrolysis equipment 110 to maintain the concentration of the internal gas. That is, after the internal gas of the water electrolysis equipment 110 has been sufficiently replaced with carbon dioxide, the CPU 41 stops the supply of carbon dioxide from the carbon dioxide supply unit 190. Specifically, the CPU 41 stops carbon dioxide from flowing into the water electrolysis equipment 110 and the second intermediate connection line 158 by closing the second valve 134, the fourth valve 138, and the seventh valve 144. The CPU 41 also stops carbon dioxide from flowing from the water electrolysis equipment 110 to the hydrogen delivery line 152 by closing the first valve 132. As a result, the internal gas of the water electrolysis equipment 110 is sealed, and the concentration of the internal gas (specifically, the concentration of hydrogen gas) of the water electrolysis equipment 110 is maintained.

[0060] In this embodiment of the methanation equipment 100, the hydrogen gas concentration inside the Sabatier reaction equipment 120 is replaced with carbon dioxide until it reaches a predetermined concentration, and only then is the internal gas of the water electrolysis equipment 110 replaced with carbon dioxide. Therefore, with this methanation equipment 100, compared to the case where the internal gases of the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are replaced with carbon dioxide at the same time, the situation in which the internal gas of the water electrolysis equipment 110 is not replaced with carbon dioxide and the operation of the methanation equipment 100 is stopped is less likely to occur.

[0061] [Third Embodiment] As shown in Figure 5, in this embodiment, first, as step S302, the CPU 41 stops the Sabatier reaction and then gradually reduces the amount of hydrogen gas produced from the water electrolysis equipment 110. Specifically, the CPU 41 stops the Sabatier reaction by cooling the Sabatier reaction equipment 120 while continuing to operate the water electrolysis equipment 110. Then, after confirming that the Sabatier reaction has stopped in the Sabatier reaction equipment 120, the CPU 41 reduces the amount of hydrogen gas produced by reducing the amount of water electrolyzed by weakening the power supply to the water electrolysis equipment 110. In other words, the concentration of hydrogen gas in the mixed gas of hydrogen and carbon dioxide supplied to the Sabatier reaction equipment 120 is reduced to a predetermined value.

[0062] Next, in step S304, the CPU 41 confirms that the hydrogen concentration in the Sabatier reactor 120, more specifically the hydrogen concentration in the methane delivery line 164, has reached a predetermined target concentration, and then seals the Sabatier reactor 120 to maintain the concentration of the internal gas. Specifically, the CPU 41 stops the flow of carbon dioxide into the Sabatier reactor 120 by closing the fifth valve 140. The CPU 41 also seals the internal gas of the Sabatier reactor 120 by closing the sixth valve 142, and maintains the concentration of the internal gas (specifically, the concentration of hydrogen gas) in the Sabatier reactor 120. Furthermore, the CPU 41 prevents the pressure inside the hydrogen delivery line 152 from rising by opening the second valve 134 and releasing the hydrogen gas generated by the water electrolysis equipment 110 from the hydrogen release line 156.

[0063] Next, in step S306, the CPU 41 stops the operation of the water electrolysis equipment 110 when the hydrogen concentration in the Sabatier reaction equipment 120 reaches a predetermined target concentration. Specifically, the CPU 41 stops the electrolysis of water by cutting off the power supply to the water electrolysis equipment 110.

[0064] Next, in step S308, the CPU 41 replaces the internal gases of the water electrolysis equipment 110, the second intermediate connection line 158, and the first intermediate connection line 154 with carbon dioxide. Specifically, the CPU 41 supplies carbon dioxide to the water electrolysis equipment 110 by opening the seventh valve 144. In addition, by keeping the second valve 134 open, the internal gases in the second intermediate connection line 158, the first intermediate connection line 154, and the hydrogen delivery line 152 are replaced with carbon dioxide and released from the hydrogen release line 156.

[0065] Next, in step S310, the CPU 41 seals the water electrolysis equipment 110 to maintain the concentration of the internal gas. That is, after the internal gas of the water electrolysis equipment 110 has been sufficiently replaced with carbon dioxide, the CPU 41 stops the supply of carbon dioxide from the carbon dioxide supply unit 190. Specifically, the CPU 41 stops carbon dioxide from flowing into the water electrolysis equipment 110 and the second intermediate connection line 158 by closing the second valve 134, the fourth valve 138, and the seventh valve 144. The CPU 41 also stops carbon dioxide from flowing from the water electrolysis equipment 110 to the hydrogen delivery line 152 by closing the first valve 132. As a result, the internal gas of the water electrolysis equipment 110 is sealed, and the concentration of the internal gas (specifically, the concentration of hydrogen gas) of the water electrolysis equipment 110 is maintained.

[0066] In the methanation equipment 100 of this embodiment, the internal gas of the Sabatier reaction equipment 120 is replaced with a gas whose hydrogen gas concentration has been adjusted to a predetermined concentration by carbon dioxide supplied during the operation of the water electrolysis equipment 110. In other words, when the Sabatier reaction equipment 120 is shut down, its internal gas is replaced with a pre-adjusted gas. Therefore, with this methanation equipment 100, it is easier to prevent the methanation equipment 100 from being shut down while there is variation in the hydrogen gas concentration of the internal gas of the Sabatier reaction equipment 120.

[0067] [Fourth Embodiment] As shown in Figure 6, in this embodiment, first, as step S402, the CPU 41 stops the Sabatier reaction equipment 120. Specifically, the CPU 41 stops the Sabatier reaction by cooling the Sabatier reaction equipment 120 while continuing to operate the water electrolysis equipment 110. Then, after confirming that the Sabatier reaction has stopped in the Sabatier reaction equipment 120, the CPU 41 stops the electrolysis of water by cutting off the power supply to the water electrolysis equipment 110 and also stops the gas supply to the Sabatier reaction equipment 120 by closing the fifth valve 140.

[0068] Next, in step S404, the CPU 41 supplies carbon dioxide to the water electrolysis equipment 110 and the Sabatier reaction equipment 120. Specifically, the CPU 41 supplies carbon dioxide to the water electrolysis equipment 110 by opening the fifth valve 140 and the seventh valve 144 while the third valve 136 is open. As a result, the internal gas of the water electrolysis equipment 110 is replaced with carbon dioxide. Also, since the second valve 134 is not opened, the carbon dioxide and residual hydrogen discharged from the water electrolysis equipment 110 are supplied to the Sabatier reaction equipment 120. Therefore, they are replaced with carbon dioxide supplied to the Sabatier reaction equipment 120.

[0069] Next, in step S406, the CPU 41 confirms that the hydrogen concentration in the Sabatier reactor 120, more specifically the hydrogen concentration in the methane delivery line 164, has reached a predetermined target concentration, and then seals the Sabatier reactor 120 to maintain the concentration of the internal gas. Specifically, the CPU 41 stops the flow of carbon dioxide into the Sabatier reactor 120 by closing the fifth valve 140. Furthermore, by closing the sixth valve 142, the internal gas of the Sabatier reactor 120 is sealed, and the concentration of the internal gas (specifically, the concentration of hydrogen gas) of the Sabatier reactor 120 is maintained.

[0070] Next, in step S408, the CPU 41 seals the water electrolysis equipment 110 to maintain the concentration of the internal gas. That is, by closing the first valve 132 and the seventh valve 144, the CPU 41 stops the supply of carbon dioxide to the water electrolysis equipment 110 and also stops the flow of carbon dioxide from the water electrolysis equipment 110 to the hydrogen delivery line 152. As a result, the internal gas of the water electrolysis equipment 110 is kept in a state where it has been replaced with carbon dioxide.

[0071] In the methanation equipment 100 of this embodiment, the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are shut down when their internal gases are replaced with carbon dioxide at the same time. As a result, the time required to replace the internal gases of the water electrolysis equipment 110 and the Sabatier reaction equipment 120 with carbon dioxide is shortened in this methanation equipment 100. Therefore, with this methanation equipment 100, the amount of carbon dioxide used can be reduced compared to when the internal gases of the water electrolysis equipment 110 and the Sabatier reaction equipment 120 are replaced with carbon dioxide at different times.

[0072] (Shutdown of methanation equipment 100) Furthermore, after executing one of the catalyst protection methods described above as an operation stop mode, the CPU 41 shuts down the entire methanation equipment 100. Specifically, the CPU 41 stops supplying power to pumps that deliver pure water, carbon dioxide gas, and methane gas (not shown), as well as to components that perform temperature control, etc.

[0073] (Other embodiments) In the above description, a methanation plant 100 for synthesizing methane was used as an example of a synthetic compound manufacturing system, and a Sabatier reaction plant 120 was used as an example of a reaction plant. The technology relating to this disclosure is not limited to the synthesis of methane or the Sabatier reaction, but can also be applied to technologies for reacting carbon dioxide with hydrogen gas. For example, it can be applied to reactions that produce carbon monoxide and water from carbon dioxide and hydrogen (reverse shift reaction), reactions that produce methanol, reactions that produce ethylene, and synthetic compound manufacturing systems equipped with these reaction plants.

[0074] Furthermore, for example, the technology relating to this disclosure may also be applied to reactions that produce other carbon compounds, and to synthetic compound manufacturing systems equipped with such reaction facilities. For example, (CH2) n This can also be applied to reactions that produce e-fuel and water, and to synthetic compound manufacturing systems equipped with these reaction facilities.

[0075] While embodiments of this disclosure have been described above with reference to the attached drawings, it is clear that any person with ordinary skill in the art to which this disclosure belongs could conceive of various modifications or applications within the scope of the technical idea described in the claims, and these too are naturally understood to fall within the technical scope of this disclosure. [Explanation of Symbols]

[0076] 32 Control device 40 Control Unit 41 CPU 42 RAM 43 ROM 44 bus 45 I / O 46 Programs 50 Valve control unit 100 Methanation equipment (an example of equipment for manufacturing synthetic compounds) 110 Water electrolysis equipment 120 Sabatier Reaction Facility (An example of a reaction facility) 132 First Valve 134 Second valve 136 Third valve 138 Fourth valve 140 Fifth Valve 142 Sixth Valve 144 Seventh Valve 148 Pure water supply line 150 Water-Oxygen Delivery Line 152 Hydrogen delivery line 154 First intermediate connection line 156 Hydrogen emission line 158 Second Intermediate Connection Line 160 carbon dioxide supply lines 162 Hydrogen-carbon dioxide mixing line 164 Methane delivery line 166 Methane Supply Unit 170 Hydrogen gas concentration meter 180 Pure water supply section 190 Carbon Dioxide Supply Department

Claims

1. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, It has, After the reaction has stopped, the water electrolysis equipment replaces the internal gas with carbon dioxide. The reaction equipment begins the replacement of the internal gas with carbon dioxide after the internal gas of the water electrolysis equipment has been replaced with carbon dioxide, and the replacement process ends when the internal hydrogen gas concentration reaches a predetermined concentration. Synthetic compound manufacturing equipment.

2. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, It has, After the reaction has stopped, the reaction equipment is replaced with carbon dioxide until the internal hydrogen gas concentration reaches a predetermined level. In the aforementioned water electrolysis equipment, after the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration, the replacement of the internal gas with carbon dioxide is initiated, and the replacement process is completed when the internal gas has been replaced with carbon dioxide. Synthetic compound manufacturing equipment.

3. The reaction equipment is supplied with a gas whose hydrogen gas concentration has been adjusted to a predetermined concentration by carbon dioxide during the operation of the water electrolysis equipment, thereby replacing the internal gas. The synthetic compound manufacturing apparatus according to claim 2.

4. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, It has, After the reaction in the reaction equipment has stopped, the water electrolysis equipment is supplied with carbon dioxide to replace the internal gas. The reaction apparatus begins the replacement of its internal gas with carbon dioxide when carbon dioxide is supplied from the water electrolysis apparatus, and the replacement process ends when the internal hydrogen gas concentration reaches a predetermined concentration. Synthetic compound manufacturing equipment.

5. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, In a synthetic compound manufacturing facility having, After stopping the reaction, the internal gas of the water electrolysis equipment is replaced with carbon dioxide. After the internal gas of the water electrolysis equipment has been replaced with carbon dioxide, the process of replacing the internal gas of the reaction equipment with carbon dioxide is started, and the replacement process is terminated when the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration. Catalyst protection method.

6. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, In a synthetic compound manufacturing facility having, After stopping the reaction, the internal gas of the reaction equipment is replaced with carbon dioxide until the hydrogen gas concentration inside the equipment reaches a predetermined concentration. After the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration, the process of replacing the internal gas of the water electrolysis equipment with carbon dioxide is started and the replacement process is completed when the internal gas is replaced with carbon dioxide. Catalyst protection method.

7. During the operation of the water electrolysis equipment, the internal gas of the reaction equipment is replaced with a gas supplied to the reaction equipment, the gas whose hydrogen gas concentration has been adjusted to a predetermined concentration using carbon dioxide. A catalyst protection method according to claim 6.

8. A water electrolysis facility that produces hydrogen by electrolyzing water, A reaction apparatus for obtaining a synthetic compound by reacting hydrogen obtained from the aforementioned water electrolysis apparatus with carbon dioxide, In a synthetic compound manufacturing facility having, After stopping the reaction in the reaction equipment, carbon dioxide is supplied to the water electrolysis equipment to replace the internal gas of the water electrolysis equipment. The carbon dioxide discharged from the water electrolysis equipment is supplied to the reaction equipment to begin the replacement of the internal gas of the reaction equipment with carbon dioxide, and the replacement operation is terminated when the hydrogen gas concentration inside the reaction equipment reaches a predetermined concentration. Catalyst protection method.

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