Manufacturing system for synthetic compounds

Abstract

This disclosure aims to provide a synthetic compound manufacturing system that improves the efficiency of synthetic compound production compared to the case where hydrogen gas at atmospheric pressure is supplied to the reactor. [Solution] The methanation equipment 100 includes a water electrolysis equipment 150 that obtains hydrogen gas by electrolyzing water at atmospheric pressure, a Sabatier reaction equipment 102 that obtains methane by reacting hydrogen gas with carbon dioxide, and a first hydrogen compressor 172A and a second hydrogen compressor 172B that increase the pressure of the hydrogen gas obtained from the water electrolysis equipment 150 by repeatedly storing and releasing hydrogen gas using a hydrogen storage alloy, and supply the increased-pressure hydrogen gas to the Sabatier reaction equipment 102.

Description

Technical Field

[0001] The present disclosure relates to a synthetic compound manufacturing system.

Background Art

[0002] For example, Patent Document 1 discloses a hydrocarbon generation system including a hydrocarbon generation device, an electrolysis device, a steam supply line, and a heat exchanger. The hydrocarbon generation device generates hydrocarbons and steam by an exothermic reaction of carbon dioxide gas and hydrogen. The electrolysis device generates hydrogen to be supplied to the hydrocarbon generation device from raw material steam. The steam supply line evaporates raw material liquid water to generate raw material steam and supplies the raw material steam to the electrolysis device. The heat exchanger utilizes the reaction heat generated in the hydrocarbon generation device for the evaporation of the raw material liquid water in the steam supply line via heat medium oil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a hydrocarbon generation system as shown in Patent Document 1, it is difficult to increase the pressure of hydrogen gas in order to suppress crossover in the electrolysis device. On the other hand, in the hydrocarbon generation device, from the viewpoint of improving the efficiency of the reaction, it may be desirable that the pressures of hydrogen gas and carbon dioxide gas are high.

[0005] An object of the present disclosure is to provide a synthetic compound manufacturing system that improves the production efficiency of synthetic compounds as compared with the case of supplying hydrogen gas at atmospheric pressure to a reactor.

Means for Solving the Problems

[0006] The first embodiment of the synthetic compound manufacturing system comprises a water electrolysis facility that obtains hydrogen gas by electrolyzing water at atmospheric pressure; a reaction facility that obtains a synthetic compound by reacting hydrogen gas with carbon dioxide; and a hydrogen storage alloy compressor that increases the pressure of the hydrogen gas obtained from the water electrolysis facility by repeatedly storing and releasing hydrogen gas using a hydrogen storage alloy, and supplies the increased-pressure hydrogen gas to the reaction facility.

[0007] The synthetic compound production system according to this embodiment is equipped with a hydrogen storage alloy compressor that increases the pressure of the hydrogen gas supplied to the reactor. Therefore, by increasing the pressure of the hydrogen gas supplied to the reactor, this synthetic compound production system can improve the efficiency of synthetic compound production compared to the case where hydrogen gas is supplied to the reactor at atmospheric pressure.

[0008] The synthetic compound manufacturing system of the second embodiment comprises a plurality of hydrogen storage alloy compressors in which the repeated absorption and release of hydrogen gas are in different phases, in addition to the synthetic compound manufacturing system of the first embodiment.

[0009] The synthetic compound manufacturing system according to this embodiment is equipped with a plurality of hydrogen storage alloy compressors in which the repeated absorption and release of hydrogen gas occurs in different phases. Therefore, with this synthetic compound manufacturing system, by sequentially operating the hydrogen storage alloy compressors, it is possible to continuously supply hydrogen gas at a high pressure to the reactor.

[0010] The synthetic compound manufacturing system of the third embodiment further comprises, in the synthetic compound manufacturing system of the first or second embodiment, piping connecting from the heat exhaust side of the heat exchanger that cools the hydrogen gas obtained from the water electrolysis equipment to the heat source of the hydrogen storage alloy compressor.

[0011] The synthetic compound manufacturing system according to this embodiment further includes piping connecting the heat exhaust side of a heat exchanger that cools hydrogen gas to the heat source of a hydrogen storage alloy compressor. In other words, the synthetic compound manufacturing system according to this embodiment uses waste heat obtained by cooling hydrogen gas from a water electrolysis facility as the heat source for the hydrogen storage alloy compressor. As a result, the energy consumption of this synthetic compound manufacturing system is reduced compared to a system where an independent heat source is used as the heat source for the hydrogen storage alloy compressor.

[0012] The synthetic compound manufacturing system of the fourth embodiment further comprises a heat transfer device that transfers the heat generated by the reaction equipment to the water supplied to the water electrolysis equipment, in addition to the synthetic compound manufacturing system of the first to third embodiments.

[0013] In this embodiment of the synthetic compound production system, the heat generated when the reaction equipment reacts hydrogen gas and carbon dioxide to obtain a synthetic compound is transferred to the water supplied to the water electrolysis equipment. Compared to cases where heating the water supplied to the water electrolysis cell stack and cooling the reaction equipment are performed separately, the amount of energy required to produce the synthetic compound can be reduced. [Effects of the Invention]

[0014] According to this disclosure, a synthetic compound manufacturing system is provided that improves the efficiency of synthetic compound production compared to the case where hydrogen gas at atmospheric pressure is supplied to the reactor. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram showing a methanation system according to the present invention. [Figure 2] This diagram illustrates the operation of a hydrogen storage alloy compressor according to an embodiment, and shows the relationship between the amount of hydrogen contained in the hydrogen storage alloy and the hydrogen gas pressure around the hydrogen storage alloy. [Figure 3]This is a diagram for explaining the operation of the hydrogen storage alloy compressor according to the embodiment following FIG. 2. FIG. 3(A) is a diagram showing the state where the hydrogen storage alloy at low temperature absorbs the surrounding hydrogen gas. FIG. 3(B) is a diagram showing the state where the hydrogen storage alloy is heated and the pressure of the hydrogen gas around the hydrogen storage alloy increases. FIG. 3(C) is a diagram showing the state where the pressure of the hydrogen gas around the hydrogen storage alloy decreases and the hydrogen gas absorbed by the hydrogen storage alloy is released. FIG. 3(D) is a diagram showing the state where the hydrogen storage alloy is cooled and the hydrogen storage alloy becomes capable of absorbing hydrogen gas. [Figure 4] This is a diagram for explaining the control device included in the methanation facility. [Figure 5] This is a timing diagram for explaining the operation of the methanation facility according to the embodiment, showing the state where the control unit controls the valve to increase the pressure of the hydrogen gas supplied from the water electrolysis facility by the hydrogen storage alloy compressor. [Figure 6] Following FIG. 5, this is a diagram for explaining the operation of the methanation facility according to the embodiment, showing the state of the pressure increasing section from time 1 to time 2 in FIG. 5. [Figure 7] Following FIG. 6, this is a diagram for explaining the operation of the methanation facility according to the embodiment, showing the state of the pressure increasing section from time 2 to time 3 in FIG. 5. [Figure 8] Following FIG. 7, this is a diagram for explaining the operation of the methanation facility according to the embodiment, showing the state of the pressure increasing section from time 3 to time 4 in FIG. 5. [Figure 9] Following FIG. 8, this is a diagram for explaining the operation of the methanation facility according to the embodiment, showing the state of the pressure increasing section from time 4 to the next time 1 in FIG. 5. [Embodiments for Carrying Out the Invention]

[0016] Hereinafter, an example of an embodiment of the present disclosure will be described while referring to the drawings. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0017] (Configuration) (Methanation Facility 100) FIG. 1 shows a methanation facility 100 according to an embodiment of the present disclosure. The methanation facility 100 is an example of a synthetic compound manufacturing system in the present disclosure. The methanation facility 100 includes a Sabatier reaction facility 102, a raw material gas supply unit 140, a heat transfer facility 190, and a control device 32. The Sabatier reaction facility 102 is an example of the "reaction facility" in the present disclosure.

[0018] (Sabatier Reaction Facility 102) The Sabatier reaction facility 102 is a facility that generates methane and water as synthetic compounds by the Sabatier reaction. As shown in FIG. 1, the Sabatier reaction facility 102 includes a first Sabatier reactor 106, a first water separation unit 110, a second Sabatier reactor 112, and a second water separation unit 116.

[0019] The first Sabatier reactor 106 generates methane and water from the mixed gas of hydrogen gas and carbon dioxide gas supplied from the mixed gas supply line 104 by the Sabatier reaction. The mixed gas of methane, water, unreacted hydrogen gas, and carbon dioxide gas generated by the first Sabatier reactor 106 is sent out to the first methane gas delivery line 108 and supplied to the second Sabatier reactor 112 as shown in FIG. 1. Further, the first methane gas delivery line 108 is provided with a first water separation unit 110 in the middle of the path from the first Sabatier reactor 106 to the second Sabatier reactor 112.

[0020] The first water separation unit 110 separates water from the mixed gas of methane and water generated by the first Sabatier reactor 106 in the first methane gas delivery line 108. Also, the water separated in the first water separation unit 110 is discharged from the first methane gas delivery line 108 as shown in FIG. 1.

[0021] The second Sabatier reactor 112 converts unreacted hydrogen and carbon dioxide gas from the mixed gas supplied from the first methane gas delivery line 108 into methane and water via the Sabatier reaction. In other words, the second Sabatier reactor 112 increases the purity of methane contained in the mixed gas. The mixed gas produced by the second Sabatier reactor 112 is sent to the second methane gas delivery line 114, as shown in Figure 1, and supplied to the methane gas supply unit 118. The second methane gas delivery line 114 also has a second water separation unit 116 located along its path from the second Sabatier reactor 112 to the methane gas supply unit 118.

[0022] The second water separation unit 116 separates water from the methane and water mixture gas produced by the second Sabatier reactor 112 in the second methane gas delivery line 114. The water separated in the second water separation unit 116 is then discharged from the second methane gas delivery line 114, as shown in Figure 1.

[0023] The methane supplied to the methane gas supply unit 118 may be used for any purpose.

[0024] (Raw material gas supply unit 140) As shown in Figure 1, the raw gas supply unit 140 includes a hydrogen-carbon dioxide mixer 146, a carbon dioxide supply unit 142, and a hydrogen supply unit 144.

[0025] (Hydrogen-carbon dioxide mixer 146) As described above, the hydrogen-carbon dioxide mixer 146 mixes hydrogen gas and carbon dioxide gas and supplies the mixed gas to the mixed gas supply line 104.

[0026] (Carbon dioxide supply unit 142) The carbon dioxide supply unit 142 supplies carbon dioxide gas to the hydrogen-carbon dioxide mixer 146. The configuration of the carbon dioxide supply unit 142 can be anything.

[0027] The hydrogen supply unit 144 includes a water electrolysis equipment 150 that generates hydrogen gas, and a pressurization unit 170 that pressurizes the hydrogen gas generated by the water electrolysis equipment 150.

[0028] (Water electrolysis equipment 150) The water electrolysis equipment 150 has a so-called water electrolysis cell stack 152. The water electrolysis cell stack 152 is formed by stacking water electrolyzers, each forming an anode and a cathode with an electrolyte membrane in between. When electricity is applied, the water supplied to the anode of the water electrolysis equipment 150 is electrolyzed by the water electrolysis cell stack 152. Specifically, oxygen gas is generated at the anode of the water electrolysis cell stack 152, and hydrogen gas is generated at the cathode. The water electrolysis equipment 150 is also connected to a control device 32 and a power supply device (not shown), and the amount of electricity supplied is controlled by the control device 32, thereby controlling the amount of water electrolysis.

[0029] The anode inlet of the water electrolysis equipment 150 is connected to the pure water supply unit 192, and water is supplied from the pure water supply unit 192. A hydrogen delivery line 154 is connected to the cathode outlet of the water electrolysis equipment 150, and hydrogen gas is delivered from the hydrogen delivery line 154. In addition, a water-oxygen delivery line (not shown) is connected to the anode outlet of the water electrolysis equipment 150, and oxygen gas and undecomposed water are delivered from the water-oxygen delivery line.

[0030] As shown in Figure 1, the hydrogen delivery line 154 is connected to the booster unit 170. The hydrogen delivery line 154 is also equipped with a heat exchanger 156 and a water separation unit 182.

[0031] The heat exchanger 156 is a component that lowers the temperature of the gas sent from the water electrolysis cell stack 152 (i.e., the gas obtained from the water electrolysis equipment 150). More specifically, as shown in Figures 1 and 6, the heat exchanger 156 is connected to a cooling water line 158 through which cooling water flows, and transfers the heat from the hydrogen gas and water vapor mixed with the hydrogen gas transported in the hydrogen delivery line 154 to the cooling water flowing in the cooling water line 158. More specifically, the heat exchanger 156 cools the hydrogen gas and water vapor mixed with the hydrogen gas transported in the hydrogen delivery line 154, thereby condensing the water vapor back into liquid water. In other words, the cooling water flowing in the cooling water line 158 is heated by the heat of the hydrogen gas and the latent heat of the water. The cooling water heated in the heat exchanger 156 is then sent to the high-temperature water line 160, which is the heat exhaust side.

[0032] As shown in Figure 1, the cooling water line 158 branches upstream of the heat exchanger 156, and the branched flow path is connected to the high-temperature water line 160 via the cooling water valve 162. In other words, the high-temperature water line 160 receives both cooling water heated by the heat exchanger 156 and cooling water that flows in without passing through the heat exchanger 156.

[0033] Furthermore, a high-temperature water valve 164 is provided upstream of the connection point with the cooling water line 158 in the high-temperature water line 160. Therefore, the temperature of the cooling water flowing through the high-temperature water line 160 is controlled by the control device 32 by controlling the flow rate of the cooling water heated by the heat exchanger 156 and the cooling water that flows in without passing through the heat exchanger 156. As shown in Figure 1, the high-temperature water line 160 is connected to the pressure booster 170, and the temperature-controlled cooling water is supplied to the pressure booster 170.

[0034] The water separation unit 182 separates water from the mixed gas of hydrogen gas generated by the water electrolysis cell stack 152 and the water mixed in the hydrogen delivery line 154. The water separated in the water separation unit 182 is then discharged from the hydrogen delivery line 154, as shown in Figure 1.

[0035] (Voltage booster 170) The pressure boosting unit 170 is a component that increases the pressure of the hydrogen gas supplied from the hydrogen delivery line 154 and sends it to the hydrogen-carbon dioxide mixer 146. As shown in Figure 1, the pressure boosting unit 170 includes a first hydrogen compressor 172A, a second hydrogen compressor 172B, a first water valve 174A, a second water valve 174B, a first low-pressure hydrogen valve 176A, a second low-pressure hydrogen valve 176B, a first high-pressure hydrogen valve 178A, and a second high-pressure hydrogen valve 178B. The first hydrogen compressor 172A and the second hydrogen compressor 172B are examples of "hydrogen storage alloy compressors" in this disclosure.

[0036] The first hydrogen compressor 172A has a hydrogen storage alloy housed inside the tank. As shown in Figure 1, the first hydrogen compressor 172A is connected to a high-temperature water line 160, a hydrogen delivery line 154, and a high-pressure hydrogen delivery line 184.

[0037] The first hydrogen compressor 172A absorbs and releases hydrogen gas supplied from the hydrogen delivery line 154 using a hydrogen storage alloy. The hydrogen storage alloy in the first hydrogen compressor 172A has an equilibrium pressure that depends on the pressure and temperature of the hydrogen gas, and absorbs and releases hydrogen gas depending on the pressure and temperature of the hydrogen gas. As the temperature increases, the amount of hydrogen that can be absorbed by the hydrogen storage alloy (i.e., the volume of hydrogen gas that can be absorbed) decreases, and as the temperature decreases, the amount of hydrogen that can be absorbed increases.

[0038] The operation of the first hydrogen compressor 172A will be explained in more detail with reference to Figures 2 and 3. Figure 2 is a diagram showing the relationship between the amount of hydrogen contained in the hydrogen storage alloy housed inside the tank of the first hydrogen compressor 172A and the pressure of the hydrogen gas around the hydrogen storage alloy (i.e., the pressure of the hydrogen gas inside the tank). Figures 3(A) to 3(D) show how the hydrogen storage alloy absorbs and releases hydrogen gas.

[0039] First, in the state shown at point 1 in Figure 2, the hydrogen storage alloy absorbs the surrounding hydrogen gas up to the equilibrium pressure, as shown in Figure 3(A), when the temperature is low. As a result, the hydrogen storage alloy absorbs hydrogen from point 1 to point 2 in Figure 2.

[0040] Here, if the hydrogen storage alloy is heated from the state shown at point 2 in Figure 2, the equilibrium pressure of the hydrogen storage alloy decreases, causing the hydrogen storage alloy to release hydrogen as gas, as shown in Figure 3(B). As a result, the pressure of the hydrogen gas inside the tank increases from point 2 to point 3 in Figure 2.

[0041] Furthermore, if the gas pressure around the hydrogen storage alloy decreases from the state at point 3 in Figure 2 (for example, if hydrogen gas is released from the tank), the hydrogen storage alloy will release hydrogen as a gas until it reaches equilibrium pressure, as shown in Figure 3(C). As a result, the hydrogen gas pressure inside the tank will decrease from point 3 to point 4 in Figure 2.

[0042] Then, as the hydrogen storage alloy cools from the state shown at point 4 in Figure 2, the equilibrium pressure of the hydrogen storage alloy increases again, making it possible to absorb the surrounding hydrogen gas up to the equilibrium pressure, as shown in Figure 3(D). As a result, the pressure of the hydrogen gas inside the tank decreases from point 4 to point 1 in Figure 2.

[0043] Thus, as shown in Figures 2 and 3(A) to 3(D), by heating the hydrogen storage alloy, the first hydrogen compressor 172A can increase the hydrogen gas pressure inside the tank (i.e., from point 2 to point 3 in Figure 2). Then, by increasing the hydrogen gas pressure inside the tank, the first hydrogen compressor 172A can supply high-pressure hydrogen gas (i.e., from point 3 to point 4 in Figure 2). Furthermore, by cooling the hydrogen storage alloy, the first hydrogen compressor 172A can store hydrogen again (i.e., from point 4 to point 1, and then from point 1 to point 2 in Figure 2).

[0044] Any type of hydrogen storage alloy may be used. Examples include AB-type hydrogen storage alloys, AB2-type hydrogen storage alloys, AB5-type hydrogen storage alloys, Mg-based hydrogen storage alloys, and Pd-based hydrogen storage alloys.

[0045] The supply of hydrogen gas to the first hydrogen compressor 172A is controlled by opening and closing the first low-pressure hydrogen valve 176A. More specifically, when the first low-pressure hydrogen valve 176A is open, hydrogen gas is supplied to the first hydrogen compressor 172A from the hydrogen delivery line 154. When the first low-pressure hydrogen valve 176A is closed, the supply of hydrogen gas to the first hydrogen compressor 172A is stopped.

[0046] Furthermore, the first hydrogen compressor 172A supplies hydrogen gas to the high-pressure hydrogen delivery line 184 at a pressure higher than that of the hydrogen gas supplied from the hydrogen delivery line 154, according to the control procedure described later. The supply of hydrogen gas to the high-pressure hydrogen delivery line 184 is controlled by opening and closing the first high-pressure hydrogen valve 178A. More specifically, when the first high-pressure hydrogen valve 178A is open, high-pressure hydrogen gas is supplied from the first hydrogen compressor 172A to the high-pressure hydrogen delivery line 184. When the first high-pressure hydrogen valve 178A is closed, the supply of high-pressure hydrogen gas to the high-pressure hydrogen delivery line 184 is stopped.

[0047] The high-temperature water line 160 is connected to the first hydrogen compressor 172A via the first water valve 174A. In other words, when the first water valve 174A is open, cooling water that is hotter than that in the cooling water line 158 is supplied to the first hydrogen compressor 172A. When the first water valve 174A is closed, the supply of hot cooling water to the first hydrogen compressor 172A is stopped.

[0048] In the first hydrogen compressor 172A, the hydrogen storage alloy housed inside is heated by cooling water supplied from the high-temperature water line 160, which is hotter than the cooling water line 158. More specifically, when heating the hydrogen storage alloy, the control unit 40 opens the first water valve 174A to supply hot cooling water from the high-temperature water line 160 to the first hydrogen compressor 172A.

[0049] The cooling water supplied to the first hydrogen compressor 172A is used to heat the hydrogen storage alloy housed in the first hydrogen compressor 172A, and is then discharged from the first hydrogen compressor 172A.

[0050] In this embodiment, the method for cooling the hydrogen storage alloy housed inside the first hydrogen compressor 172A is not particularly limited. In this description, heat is dissipated by heat transfer methods such as heat pipes and heat sinks provided in the first hydrogen compressor 172A. Alternatively, for example, the hydrogen storage alloy may be cooled using cooling water by supplying cooling water through the cooling water line 158 with the high-temperature water valve 164 closed (i.e., the supplied cooling water does not pass through the heat exchanger 156). Alternatively, for example, another cooling water line (not shown) may be provided, and the alloy may be cooled by cooling water supplied from that other cooling water line.

[0051] In this manner, the first hydrogen compressor 172A, based on the control of the control device 32, supplies and delivers hydrogen gas, and controls the temperature of the hydrogen storage alloy via the first water valve 174A, the first low-pressure hydrogen valve 176A, and the first high-pressure hydrogen valve 178A.

[0052] The second hydrogen compressor 172B houses the hydrogen storage alloy inside the tank. As shown in Figure 1, the second hydrogen compressor 172B is connected to the high-temperature water line 160, the hydrogen delivery line 154, and the high-pressure hydrogen delivery line 184. In other words, the second hydrogen compressor 172B has the same configuration as the first hydrogen compressor 172A. Based on the control of the control device 32, the second hydrogen compressor 172B supplies and delivers hydrogen gas, and controls the temperature of the hydrogen storage alloy via the second water valve 174B, the second low-pressure hydrogen valve 176B, and the second high-pressure hydrogen valve 178B.

[0053] The hydrogen gas sent from the first hydrogen compressor 172A or the second hydrogen compressor 172B to the high-pressure hydrogen delivery line 184 is temporarily stored in the storage unit 180. The storage unit 180 is also connected to the hydrogen-carbon dioxide mixer 146 through the hydrogen gas supply line 186. In other words, the storage unit 180 buffers the pressure fluctuations of the hydrogen gas sent from the high-pressure hydrogen delivery line 184.

[0054] (Heat transfer equipment 190) The heat transfer equipment 190 is a system for cooling the first Sabatier reactor 106 and the second Sabatier reactor 112. More specifically, as shown in Figure 1, the heat transfer equipment 190 is a system connected to the first Sabatier reactor 106 and the second Sabatier reactor 112, through which a refrigerant (not shown) circulates. The heat transfer equipment 190 removes the heat generated by the Sabatier reaction in the first Sabatier reactor 106 and the second Sabatier reactor 112 using the refrigerant.

[0055] Furthermore, as shown in Figure 1, the heat transfer equipment 190 has a heat exchanger 194 for cooling the refrigerant, which is provided in the pure water supply unit 192. In other words, the heat transfer equipment 190 uses the refrigerant to transfer the heat generated by the first Sabatier reactor 106 and the second Sabatier reactor 112 to the pure water supply unit 192. In other words, the heat transfer equipment 190 heats the water supplied to the water electrolysis cell stack 152. The heat transfer equipment 190 is an example of a "heat transfer equipment" in this disclosure.

[0056] In this embodiment, the heat transfer equipment 190 is controlled by the control device 32. Specifically, the amount of heat transferred from the first Sabatier reactor 106 and the second Sabatier reactor 112 to the pure water supply unit 192 is controlled by the control device 32.

[0057] (Control device 32) The control device 32 is a device that controls the methanation equipment 100. Figure 4 shows a block diagram illustrating the hardware configuration of the control device 32 in this embodiment. As shown in Figure 4, 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.

[0058] 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 4, has 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.

[0059] The CPU 41 is a central processing unit that executes various programs 46, including program 46, that operate the methanation equipment 100, and controls each part. 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.

[0060] In the control unit 40, the CPU 41 reads various programs 46, including program 46, from the ROM 43 and executes program 46 using RAM 42 as the work area. By executing program 46, the CPU 41 realizes various functions that control each part of the control device 32.

[0061] The valve control unit 50 is a component that controls a total of eight valves, including the cooling water valve 162, the high-temperature water valve 164, the first water valve 174A, the second water valve 174B, the first low-pressure hydrogen valve 176A, the second low-pressure hydrogen valve 176B, the first high-pressure hydrogen valve 178A, and the second high-pressure hydrogen valve 178B, according to instructions from the CPU 41. More specifically, it drives the total of eight valves to switch between an open state and a closed state according to instructions from the CPU 41. The valve control unit 50 is capable of individually switching between the open state and the closed state for each of the eight valves.

[0062] By the way, in the water electrolysis equipment 150 according to this embodiment, it is difficult to increase the pressure of the hydrogen gas in the hydrogen delivery line 154. Specifically, if the pressure in the hydrogen delivery line 154 is increased unnecessarily, the hydrogen gas will mix with the gases on the anode and cathode sides (i.e., hydrogen gas and oxygen gas) in the water electrolysis cell stack 152. In this embodiment, the water electrolysis cell stack 152 electrolyzes water at atmospheric pressure and supplies hydrogen gas to the hydrogen delivery line 154 at atmospheric pressure (or a pressure equivalent to atmospheric pressure).

[0063] On the other hand, in the Sabatier reaction apparatus 102, it is desirable that the pressures of hydrogen gas and carbon dioxide gas be high in order to increase the efficiency of the Sabatier reaction. For this reason, it is desirable that the pressure of the hydrogen gas supplied to the hydrogen-carbon dioxide mixer 146 be high.

[0064] Next, the procedure by which the control device 32 increases the pressure of hydrogen gas in the methanation equipment 100 of this disclosure will be explained with reference to Figures 5 to 9.

[0065] (Hydrogen gas pressurization procedure) Figure 5 is a timing diagram showing how the control unit 40 in this embodiment increases the hydrogen gas pressure by switching the open and closed states of various valves. In Figure 5, the temperature of the hydrogen storage alloy inside the first hydrogen compressor 172A is shown as "First Hydrogen Compressor 172 Temperature," and the pressure of the hydrogen gas inside the first hydrogen compressor 172A is shown as "First Hydrogen Compressor 172 Pressure." Furthermore, the pressure when the internal pressure inside the first hydrogen compressor 172A is low is the pressure of the hydrogen gas supplied from the hydrogen delivery line 154, and the pressure when the internal pressure inside the first hydrogen compressor 172A is high is the pressure of the hydrogen gas supplied to the high-pressure hydrogen delivery line 184. The same applies to the second hydrogen compressor 172B.

[0066] As shown in Figure 5, the control operation of the control unit 40 causes the first hydrogen compressor 172A to enter four states: storage, pressurization, release, and cooling. The state of each process in the boosting unit 170 is shown in Figures 6 to 9, respectively. First, the control operation for the first hydrogen compressor 172A will be explained.

[0067] During the period from time 1 to 2, the control unit 40 performs a storage process as shown in Figure 6, by closing the first water valve 174A, opening the first low-pressure hydrogen valve 176A, and closing the first high-pressure hydrogen valve 178A. As a result, during the period from time 1 to 2, the temperature of the first hydrogen compressor 172A becomes low. Also, the internal pressure of the first hydrogen compressor 172A becomes low. This process corresponds to the state from point 1 to point 2 in Figure 2. During this process, hydrogen gas is absorbed into the hydrogen storage alloy inside the first hydrogen compressor 172A.

[0068] During the period from 2 to 3 elapsed time, the control unit 40 performs a pressurizing process as shown in Figure 7, by opening the first water valve 174A, closing the first low-pressure hydrogen valve 176A, and closing the first high-pressure hydrogen valve 178A (i.e., no switching occurs). This process corresponds to the state from point 2 to point 3 in Figure 2. As a result, as shown in Figure 5, the temperature of the first hydrogen compressor 172A increases. In addition, the internal pressure of the first hydrogen compressor 172A increases due to the release of hydrogen gas from the hydrogen storage alloy. Note that during the period from 2 elapsed time, the internal pressure of the first hydrogen compressor 172A is high.

[0069] During the period from 3 to 4 elapsed time, the control unit 40 performs a discharge process as shown in Figure 8, by opening the first water valve 174A (i.e., no switching), closing the first low-pressure hydrogen valve 176A (i.e., no switching), and opening the first high-pressure hydrogen valve 178A. This process corresponds to the state from point 3 to point 4 in Figure 2. As a result, hydrogen gas is discharged from the first hydrogen compressor 172A to the high-pressure hydrogen discharge line 184, as shown in Figure 5. In addition, the discharge of hydrogen gas from the first hydrogen compressor 172A causes the internal pressure of the first hydrogen compressor 172A to decrease.

[0070] During the period from time 4 to 1, the control unit 40 performs a cooling process as shown in Figure 9, closing the first water valve 174A, closing the first low-pressure hydrogen valve 176A (i.e., no switching), and closing the first high-pressure hydrogen valve 178A. As a result, as shown in Figure 5, the supply of hydrogen gas from the first hydrogen compressor 172A to the high-pressure hydrogen delivery line 184 stops. Also, the temperature of the first hydrogen compressor 172A decreases. This process corresponds to the state from point 4 to point 1 in Figure 2.

[0071] Then, as shown in Figure 5, the control unit 40 repeatedly controls the first hydrogen compressor 172A to switch between the open and closed states of each valve. In other words, the first hydrogen compressor 172A repeatedly takes on four states: storage, pressurization, release, and cooling, under the control of the control unit 40. In the following explanation, the series of periods from one storage process to the next will be referred to as a period. Furthermore, the timing of each process state within that period will be referred to as a phase.

[0072] Furthermore, as shown in Figure 5, the control unit 40 controls the second hydrogen compressor 172B in the same way as the first hydrogen compressor 172A. That is, when the second hydrogen compressor 172B is in the state of each process, the open / closed state of the second water valve 174B corresponds to the open / closed state of the water valve when the first hydrogen compressor 172A is in the state of the same process. Also, when the second hydrogen compressor 172B is in the state of each process, the open / closed state of the second low-pressure hydrogen valve 176B corresponds to the open / closed state of the low-pressure hydrogen valve when the first hydrogen compressor 172A is in the state of the same process. Also, when the second hydrogen compressor 172B is in the state of each process, the open / closed state of the second high-pressure hydrogen valve 178B corresponds to the open / closed state of the high-pressure hydrogen valve when the first hydrogen compressor 172A is in the state of the same process.

[0073] Here, as shown in Figure 5, the processes of the first hydrogen compressor 172A and the second hydrogen compressor 172B are performed at different times. Specifically, as shown in Figure 6, when the first hydrogen compressor 172A is in the absorption process, the control unit 40 sets the second hydrogen compressor 172B to the release process. Also, as shown in Figure 7, when the first hydrogen compressor 172A is in the pressurizing process, the control unit 40 sets the second hydrogen compressor 172B to the cooling process. Furthermore, as shown in Figure 8, when the first hydrogen compressor 172A is in the release process, the control unit 40 sets the second hydrogen compressor 172B to the absorption process. And, as shown in Figure 9, when the first hydrogen compressor 172A is in the cooling process, the control unit 40 sets the second hydrogen compressor 172B to the pressurizing process.

[0074] In other words, as shown in Figure 5, the first hydrogen compressor 172A and the second hydrogen compressor 172B each take on four states based on the same period length, but the phases in which they take on these states are different. To put it another way, the control unit 40 causes the first hydrogen compressor 172A and the second hydrogen compressor 172B to repeat each process in the same way, while differentiating their phases.

[0075] Next, the operation and effects of this embodiment will be described.

[0076] (Mechanism of Action and Effects) The methanation equipment 100 of this disclosure includes a first hydrogen compressor 172A and a second hydrogen compressor 172B that increase the pressure of the hydrogen gas supplied to the Sabatier reactor 102. Therefore, with this methanation equipment 100, the methane production efficiency can be improved compared to when hydrogen gas at atmospheric pressure is supplied to the first Sabatier reactor 106 by increasing the pressure of the hydrogen gas supplied to the Sabatier reactor (specifically, the first Sabatier reactor 106).

[0077] Furthermore, the methanation equipment 100 of this disclosure includes a first hydrogen compressor 172A and a second hydrogen compressor 172B, which have different phases for repeated hydrogen gas absorption and release. Therefore, with this methanation equipment 100, by sequentially operating the first hydrogen compressor 172A and the second hydrogen compressor 172B, it is possible to continuously supply high-pressure hydrogen gas to the first Sabatier reactor 106.

[0078] Furthermore, the methanation equipment 100 of this disclosure is further equipped with a high-temperature water line 160, which is a pipe connecting the exhaust heat side of the heat exchanger 156 that cools the hydrogen gas to the heat sources of the first hydrogen compressor 172A and the second hydrogen compressor 172B. In other words, the methanation equipment 100 of this disclosure uses waste heat obtained by cooling the hydrogen gas obtained from the water electrolysis equipment 150 as the heat source for the first hydrogen compressor 172A and the second hydrogen compressor 172B.

[0079] As a result, the energy consumption of this methanation equipment 100 is reduced compared to the case where an independent heat source is used as the heat source for the first hydrogen compressor 172A or the second hydrogen compressor 172B.

[0080] Furthermore, the methanation equipment 100 in this disclosure, specifically the heat transfer equipment 190, transfers the heat generated by the Sabatier reaction in the first Sabatier reactor 102 or the second Sabatier reactor 112 to the water supplied to the water electrolysis cell stack 152. In other words, the methanation equipment 100 in this disclosure utilizes the heat generated by the Sabatier reaction in the first Sabatier reactor 102 or the second Sabatier reactor 112 to heat the water supplied to the water electrolysis cell stack 152. Therefore, by heating the water supplied to the water electrolysis cell stack 152, the heat generated in the first Sabatier reactor 102 or the second Sabatier reactor 112 can be effectively utilized, and the efficiency of water electrolysis by the water electrolysis cell stack 152 can be increased.

[0081] As a result, the methanation equipment 100 according to this embodiment can reduce the amount of energy required to produce methane compared to the case where heating the water supplied to the water electrolysis cell stack 152 and cooling the first Sabatier reactor 102 or the second Sabatier reactor 112 are performed separately.

[0082] (modified version) In the above description, the hydrogen storage alloy compressor consisted of two components: a first hydrogen compressor 172A and a second hydrogen compressor 172B. However, the embodiments described in this disclosure are not limited to these two components. For example, there may be only one hydrogen storage alloy compressor, or there may be three or more.

[0083] Furthermore, in the above description, the first hydrogen compressor 172A and the second hydrogen compressor 172B were controlled to have different phases, but the embodiments in this disclosure are not limited to this. For example, the first hydrogen compressor 172A and the second hydrogen compressor 172B may have the same phase. In the above description, the phases of the first hydrogen compressor 172A and the second hydrogen compressor 172B were opposite in the period (two processes were separated from each other out of the four processes), but the embodiments are not limited to this, and the processes may be shifted by one.

[0084] Furthermore, in the above description, waste heat obtained by cooling hydrogen gas from the water electrolysis equipment 150 was used as the heat source for the first hydrogen compressor 172A and the second hydrogen compressor 172B, but the embodiments in this disclosure are not limited to this. For example, independent heat sources may be used as the heat sources for the first hydrogen compressor 172A and the second hydrogen compressor 172B.

[0085] Furthermore, in the above description, the heat transfer equipment 190 heated the water supplied to the water electrolysis cell stack 152 using heat generated from the first Sabatier reactor 102 or the second Sabatier reactor 112; however, the embodiments in this disclosure are not limited to this. That is, heating the water supplied to the water electrolysis cell stack 152 and cooling the first Sabatier reactor 102 or the second Sabatier reactor 112 may be performed separately.

[0086] Furthermore, 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 102 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 other technologies for reacting carbon dioxide and hydrogen. 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.

[0087] 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.

[0088] In addition, in the modified example described above, even if the reaction that produces the carbon compound is an endothermic reaction, the heat (i.e., cold) generated in the endothermic reaction may be transferred to the water supplied to the water electrolysis equipment. That is, although the heat transfer equipment 190 in the above embodiment cooled the reaction equipment and heated the water supplied to the water electrolysis cell stack 152, the cold generated by heating the reaction equipment may be used to cool the gas sent out from the water electrolysis cell stack 152. In this case as well, the amount of energy required to produce the carbon compound can be reduced.

[0089] 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]

[0090] 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 a synthetic compound manufacturing system) 102 Sabatier Reaction Facility (An example of a reaction facility) 104 Mixed gas supply line 106 First Sabatier Reactor 108 First Methane Gas Delivery Line 110 First water separation section 112 Second Sabatier Reactor 114 Second methane gas delivery line 116 Second water separation section 118 Methane Gas Supply Department 140 Raw Gas Supply Department 142 Carbon Dioxide Supply Department 144 Hydrogen Supply Department 146 Hydrogen-carbon dioxide mixer 150 Water electrolysis equipment 152 Water Electrolysis Cell Stack 154 Hydrogen delivery line 156 Heat exchanger 158 Cooling water line 160 High-temperature water line 162 Cooling water valve 164 High-temperature water valve 170 Booster section 172A First Hydrogen Compressor (An example of a hydrogen storage alloy compressor) 172B Second hydrogen compressor (an example of a hydrogen storage alloy compressor) 174A First Water Valve 174B Second water valve 176A First Low-Pressure Hydrogen Valve 176B Second Low-Pressure Hydrogen Valve 178A First High-Pressure Hydrogen Valve 178B Second High-Pressure Hydrogen Valve 180 Storage section 182 Water separation section 184 High-pressure hydrogen delivery line 186 Hydrogen gas supply line 190 Heat transfer equipment 192 Pure water supply section 194 Heat exchanger

Claims

1. A water electrolysis facility that obtains hydrogen gas by electrolyzing water at atmospheric pressure, A reaction facility that obtains synthetic compounds by reacting hydrogen gas and carbon dioxide, A hydrogen storage alloy compressor increases the pressure of hydrogen gas obtained from the water electrolysis equipment by repeatedly storing and releasing hydrogen gas using a hydrogen storage alloy, and supplies the increased-pressure hydrogen gas to the reaction equipment. A synthetic compound manufacturing system equipped with the following features.

2. The system comprises a plurality of hydrogen storage alloy compressors in which the repeated absorption and release of hydrogen gas occurs in different phases. A synthetic compound production system according to claim 1.

3. The system further includes piping connecting the heat exhaust side of a heat exchanger that cools hydrogen gas obtained from the water electrolysis equipment to the heat source of the hydrogen storage alloy compressor. A synthetic compound production system according to claim 1.

4. The system further includes a heat transfer device that transfers the heat generated by the reaction equipment to the water supplied to the water electrolysis equipment. A synthetic compound manufacturing system according to any one of claims 1 to 3.

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