Steam utilization system

Abstract

To provide a steam utilization system capable of suppressing fluctuation in mass flow rate of steam in a steam utilization system.SOLUTION: A steam utilization system 1 includes: an evaporator 2 for generating water vapor W2 from water W1; a transfer device 3 for transferring the water W1 to the evaporator 2; a steam utilization device 4 for using the water vapor W2 sent from the evaporator 2; a flow path resistance adjusting valve 51 for adjusting the flow path resistance of the water W1; a liquid detecting unit 52 for detecting a pressure loss of water W1 in the flow path resistance adjusting valve 51; a steam detecting unit 53 for detecting a pressure loss of water vapor W2 in the steam utilization device 4; and a control unit 6. The control unit 6 adjusts an opening degree of the flow path resistance adjusting valve 51 based on a relative relationship between the pressure loss of the water vapor W2 and the pressure loss of the water W1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a steam utilization system. [Background technology]

[0002] The steam utilization system is used, for example, as a steam electrolysis system using a solid oxide water electrolysis cell (SOEC). In a solid oxide water electrolysis cell, water vapor supplied to the cathode of the electrolyte layer is decomposed to produce hydrogen. An evaporator is connected to the solid oxide water electrolysis cell to generate water vapor by evaporating water. Water is supplied to the evaporator by a transfer device such as a pump, and water vapor is generated in the evaporator by heating the water.

[0003] For example, Patent Document 1 describes a steam electrolysis system in which high-temperature steam generated by evaporating water using an evaporator condenser is supplied to a solid oxide type water electrolysis cell, and the waste heat of off-gas such as hydrogen generated in the solid oxide type water electrolysis cell is used to generate steam. In this steam electrolysis system, the efficiency of the system is improved by recovering the waste heat of the off-gas. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-134390 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In a solid oxide type water electrolysis cell, when the amount of hydrogen generated is changed or the like, the temperature of the water vapor in the solid oxide type water electrolysis cell and the evaporator fluctuates. When the temperature of the water vapor fluctuates, the density of the water vapor fluctuates, so that the pressure loss generated in the water vapor fluctuates, and the mass flow rate of the water vapor supplied to the solid oxide type water electrolysis cell fluctuates. Therefore, in a conventional water vapor electrolysis system, in order to prevent the fluctuation of the mass flow rate of the water vapor from affecting the generation of hydrogen in the solid oxide type water electrolysis cell, measures such as increasing the mass flow rate of the water vapor excessively are required. Even in the water vapor electrolysis system of the patent document, a configuration for suppressing the fluctuation of the mass flow rate of the water vapor supplied to the solid oxide type water electrolysis cell is not described.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a steam utilization system capable of suppressing the fluctuation of the mass flow rate of steam in a steam utilization device.

Means for Solving the Problems

[0007] One aspect of the present invention is an evaporator (2) for evaporating a liquid to generate steam, a transfer device (3) for transferring the liquid to the evaporator, a steam utilization device (4) which serves as a flow path resistance of the steam and uses the steam sent from the evaporator, a flow path resistance adjustment valve (51) disposed in a pipe (31) between the transfer device and the evaporator for adjusting the flow path resistance of the liquid in the pipe, a liquid detection unit (52) for detecting the pressure loss of the liquid in any one of the transfer device, the flow path resistance adjustment valve, and the evaporator, a steam detection unit (53) for detecting the pressure loss of the steam in any one of the evaporator and the steam utilization device, and a control unit (6) for adjusting the opening degree of the flow path resistance adjustment valve based on the relative relationship between the pressure loss of the steam and the pressure loss of the liquid. picture, The control unit is configured to increase the opening of the flow resistance adjustment valve as the ratio of the liquid pressure loss to the steam pressure loss increases. The steam detection unit detects the pressure loss of the steam by the differential pressure of the steam between the upstream and downstream sides of the steam utilization device. It is located in the steam utilization system (1). [Effects of the Invention]

[0009] (One embodiment of a steam utilization system) In the steam utilization system according to the above embodiment, measures are taken to suppress fluctuations in the mass flow rate of steam in the steam utilization device. Specifically, a liquid detection unit detects the pressure loss of the liquid, and a steam detection unit detects the pressure loss of the steam. The control unit adjusts the opening degree of the flow resistance adjustment valve based on the relative relationship between the pressure loss of the steam and the pressure loss of the liquid. Here, the steam includes both gas and a gas-liquid mixture.

[0010] In steam utilization equipment, when the steam temperature changes due to heat dissipation to the outside, etc., and the steam mass flow rate fluctuates in response to changes in steam density, the ratio of steam pressure loss to liquid pressure loss changes. At this time, the control unit adjusts the opening degree of the flow path resistance adjustment valve to suppress the change in the ratio of steam pressure loss to liquid pressure loss, thereby suppressing fluctuations in the steam mass flow rate in the steam utilization equipment.

[0011] According to the steam utilization system of the above embodiment, fluctuations in the mass flow rate of steam in the steam utilization device can be suppressed.

[0014] The reference numerals in parentheses for each component shown in each embodiment of the present invention indicate the correspondence with the reference numerals in the figures of the embodiments, but the components are not limited to those described in the embodiments. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a diagram showing the configuration of a steam utilization system according to Embodiment 1. [Figure 2] Figure 2 is an explanatory diagram illustrating the phenomenon that occurs when the temperature of a steam utilization device rises according to Embodiment 1. [Figure 3] Figure 3 is an explanatory diagram illustrating the phenomenon that occurs when the temperature of the steam utilization device decreases according to Embodiment 1. [Figure 4] Figure 4 is a graph showing the relationship between the mass flow rate of water flowing through the flow resistance control valve, the pressure loss in the water flowing through the flow resistance control valve, and the pressure loss in the steam flowing through the steam utilization device, according to Embodiment 1. [Figure 5] Figure 5 is a graph showing the relationship between the mass flow rate of water flowing through the flow resistance control valve and the ratio of the pressure loss in the water flowing through the flow resistance control valve to the pressure loss in the steam flowing through the steam utilization device, according to Embodiment 1. [Figure 6] Figure 6 is a flowchart showing the control method for a steam utilization system according to Embodiment 1. [Figure 7] Figure 7 is a configuration diagram showing a steam utilization system according to Embodiment 2. [Figure 8] Figure 8 is a configuration diagram showing a steam utilization system according to Embodiment 3. [Figure 9] Figure 9 is a configuration diagram showing a steam utilization system according to Embodiment 4. [Modes for carrying out the invention]

[0016] Preferred forms of the steam utilization systems described above will be explained. In the steam utilization system according to the above embodiment, it is preferable that the control unit is configured to increase the opening of the flow resistance regulating valve as the ratio of the liquid pressure loss to the steam pressure loss increases. This configuration means that the control unit changes the opening of the flow resistance regulating valve so that the ratio of the steam pressure loss to the liquid pressure loss approaches a constant value. It is believed that this configuration can more effectively suppress fluctuations in the steam mass flow rate in the steam utilization device. Furthermore, it is believed that there is an optimal ratio between the steam pressure loss and the liquid pressure loss from the viewpoint of suppressing fluctuations in the steam mass flow rate and suppressing the increase in the overall pressure loss of the flow path.

[0017] The reason why fluctuations in the steam mass flow rate in a steam utilization system can be suppressed more effectively is as follows: When the steam in a steam utilization system becomes hot, the mass flow rate of the steam increases due to the decrease in steam density. At this time, the ratio of liquid pressure loss to steam pressure loss changes in the direction of decreasing. Therefore, the control unit changes the opening of the flow resistance control valve in the direction of decreasing. This adjusts the ratio of liquid pressure loss to steam pressure loss in the direction of increasing. As a result, when the steam mass flow rate in the steam utilization system increases, the system adjusts the flow resistance control valve to decrease. The opening of the flow resistance control valve by the control unit is then adjusted so that the ratio of liquid pressure loss to steam pressure loss approaches a constant value.

[0018] When the steam in a steam utilization device becomes cold, the steam density increases, causing the steam mass flow rate to decrease. At this time, the ratio of liquid pressure loss to steam pressure loss changes in the direction of increasing. Therefore, the control unit changes the opening of the flow resistance control valve in the direction of increasing. This adjusts the ratio of liquid pressure loss to steam pressure loss in the direction of decreasing. As a result, when the steam mass flow rate in the steam utilization device decreases, the system adjusts the steam mass flow rate in the steam utilization device to increase. The opening of the flow resistance control valve by the control unit is then adjusted so that the ratio of liquid pressure loss to steam pressure loss approaches a constant value.

[0019] In the steam utilization system of the other embodiment described above, it is preferable that the flow meter is configured to measure the flow rate of the liquid flowing from the flow resistance regulating valve to the evaporator, and that the control unit is configured to decrease the opening of the flow resistance regulating valve as the flow rate of the liquid increases according to the flow meter. This configuration means that the control unit changes the opening of the flow resistance regulating valve so that the flow rate of the liquid approaches a constant value. It is believed that this configuration can more effectively suppress fluctuations in the mass flow rate of steam in the steam utilization device.

[0020] The reason why fluctuations in the mass flow rate of steam in a steam utilization system can be suppressed more effectively is as follows: When the steam in a steam utilization system becomes hot, the mass flow rate of both the liquid and the steam increases due to the decrease in the density of the steam. At this time, the flow rate of the liquid measured by the flow meter increases. Therefore, the control unit changes the opening of the flow resistance control valve to a smaller degree. As a result, the flow rate of the liquid in the piping decreases. Consequently, if the mass flow rate of steam in the steam utilization system increases, the system is adjusted to decrease the mass flow rate of steam in the steam utilization system.

[0021] When the steam in a steam utilization system becomes cold, the density of the steam increases, causing a decrease in the mass flow rate of both the liquid and the steam. At this time, the liquid flow rate measured by the flow meter decreases. Therefore, the control unit changes the opening of the flow resistance adjustment valve to a larger degree. This increases the liquid flow rate in the piping. As a result, if the mass flow rate of the steam in the steam utilization system decreases, the system is adjusted to increase the mass flow rate of the steam in the steam utilization system.

[0022] A preferred embodiment of the steam utilization system described above will be explained with reference to the drawings. <Embodiment 1> As shown in Figure 1, the steam utilization system 1 of this embodiment comprises an evaporator 2, a transfer device 3, a steam utilization device 4, a flow resistance adjustment valve 51, a liquid detection unit 52, a steam detection unit 53, and a control unit 6. The evaporator 2 is configured to evaporate water W1 as liquid to generate steam W2 as steam. The transfer device 3 is configured to transfer water W1 to the evaporator 2. The steam utilization device 4 acts as a flow resistance for the steam W2 and is configured to use the steam W2 sent from the evaporator 2.

[0023] The flow resistance adjustment valve 51 is located in the piping 31 between the transfer device 3 and the evaporator 2 and is used to adjust the flow resistance of water W1 in the piping 31. The liquid detection unit 52 is configured to detect the pressure loss of water W1 in the flow resistance adjustment valve 51. The steam detection unit 53 is configured to detect the pressure loss of steam W2 in the steam utilization device 4. The control unit 6 is configured to adjust the opening degree of the flow resistance adjustment valve 51 based on the relative relationship between the pressure loss of steam W2 and the pressure loss of water W1.

[0024] The steam utilization system 1 of this configuration will be described in detail below. (Steam utilization device 4 and steam utilization system 1) In this embodiment, the steam utilization device 4 constitutes a steam electrolytic device (solid oxide type water electrolytic cell, SOEC) that decomposes water vapor W2 to produce hydrogen, and the steam utilization system 1 constitutes a steam electrolytic system. The liquid used in the steam utilization system 1 is water W1, and the steam used in the steam utilization system 1 is water vapor W2. Water vapor W2 also includes a gas-liquid mixture.

[0025] Although not shown in the diagram, the steam utilization device 4 is configured using a water electrolysis cell. The water electrolysis cell is composed of an electrolyte membrane having conductivity for oxide ions, an anode formed on one surface of the electrolyte membrane, a cathode formed on the other surface of the electrolyte membrane, and a voltage application means for applying a DC voltage between the anode and the cathode. Water vapor W2 is supplied from the evaporator 2 to the cathode of the electrolyte membrane, and oxygen is produced at the anode of the electrolyte membrane.

[0026] When a DC voltage is applied between the anode and the cathode, the water vapor W2 at the cathode is decomposed into hydrogen and oxygen. Hydrogen is generated at the cathode, and the oxygen at the cathode becomes oxide ions, which pass through the electrolyte membrane to the anode and are discharged as oxygen at the anode. The hydrogen generated at the anode is stored in the hydrogen storage tank 40. The hydrogen generated at the anode may be supplied to various devices that utilize hydrogen.

[0027] The steam utilization device 4 may be a steam electrolytic device, or it may be a water electrolytic device that utilizes steam W2 in various other ways.

[0028] (Evaporator 2) As shown in Figure 1, the evaporator 2 in this embodiment receives heat from the outside and evaporates the water W1 sent from the transfer device 3 to generate steam W2. The heat applied to the evaporator 2 may be the waste heat of the off-gas discharged when hydrogen is produced in the steam utilization device 4, the waste heat of the exhaust gas discharged from an exhaust gas source other than the steam utilization device 4, or the heat generated by various heaters.

[0029] As shown in Figures 2 and 3, the evaporator 2 is formed as a container. The transfer device 3 is connected to the lower part of the evaporator 2, and the steam utilization device 4 is connected to the upper part of the evaporator 2. Inside the evaporator 2, a liquid phase 21 of water W1 is formed in the lower part, a gas-liquid mixed phase 22 in which water W1 and water vapor W2 are mixed is formed above the liquid phase 21, and a gas phase 23 of water vapor W2 is formed above the gas-liquid mixed phase 22. When the steam detection unit 53 detects the pressure loss of water vapor W2, either the water vapor W2 in the gas phase 23 or the water vapor W2 in the gas-liquid mixed phase 22 may be selected as one of the detection targets.

[0030] (transfer device 3) As shown in Figure 1, the transfer device 3 in this embodiment is composed of various pumps such as positive displacement pumps and non-positive displacement pumps. The transfer device 3 is configured to transfer water W1 from various water supply sources such as water storage tanks to the evaporator 2.

[0031] (Flow resistance adjustment valve 51) As shown in Figure 1, the flow resistance regulating valve 51 in this embodiment is located in the piping 31 between the transfer device 3 and the evaporator 2, and is capable of changing the cross-sectional area of ​​the flow path. The flow resistance in the piping 31, in other words, the resistance of the flow path of water W1 from the transfer device 3 to the evaporator 2, is adjusted by adjusting the opening degree of the flow resistance regulating valve 51. The flow resistance regulating valve 51 acts as the flow resistance of the water W1 flowing through the piping 31, and a pressure loss occurs between the upstream and downstream sides of the flow resistance regulating valve 51. By adjusting the opening degree of the flow resistance regulating valve 51, the flow rate of water W1 flowing through the piping 31 is also adjusted. Various control valves that can be operated by the control unit 6 are used for the flow resistance regulating valve 51.

[0032] (Liquid detection unit 52) As shown in Figure 1, the liquid detection unit 52 in this embodiment is configured to detect the pressure loss of water W1 by the differential pressure of water W1 on the upstream and downstream sides of the flow resistance regulating valve 51. This configuration makes it easy to detect the pressure loss of water W1. More specifically, pressure gauges 521 and 522 are placed on the upstream and downstream sides of the flow resistance regulating valve 51, with the valve in between. The differential pressure between the pressure measured by pressure gauge 521, located on the upstream side of the flow resistance regulating valve 51, and the pressure measured by pressure gauge 522, located on the downstream side of the flow resistance regulating valve 51, is detected by the liquid detection unit 52 as the pressure loss of water W1.

[0033] The liquid detection unit 52 may be configured in various ways, in addition to being configured using two pressure gauges 521 and 522, that can detect the pressure loss of water W1.

[0034] (Steam detection unit 53) As shown in Figure 1, the steam detection unit 53 in this embodiment is configured to detect the pressure loss of water vapor W2 by the differential pressure of water vapor W2 between the upstream and downstream sides of the steam utilization device 4. This configuration makes it easy to detect the pressure loss of water vapor W2. More specifically, pressure gauges 531 and 532 are placed at the inlet 41, which is the upstream position of the steam utilization device 4, and at the outlet 42, which is the downstream position of the steam utilization device 4. In other words, pressure gauges 531 and 532 are placed at the inlet 41 of the water vapor W2 in the electrolytic cell and at the outlet 42 of the hydrogen in the electrolytic cell. The differential pressure between the pressure measured by pressure gauge 531, which is located upstream of the steam utilization device 4, and the pressure measured by pressure gauge 532, which is located downstream of the steam utilization device 4, is detected by the steam detection unit 53 as the pressure loss of water vapor W2.

[0035] The steam detection unit 53 may be configured in various ways to detect the pressure loss of water vapor W2, in addition to being configured using two pressure gauges 531 and 532. For example, the steam detection unit 53 may detect the pressure loss of water vapor W2 based on at least one of the following: the temperature of water vapor W2 in the steam utilization device 4, the temperature of the electrolytic cell in the steam utilization device 4, and the temperature of the gas phase 23 (gas phase section) in the evaporator 2.

[0036] More specifically, the pressure loss of water vapor W2 occurs as the water vapor W2 passes through the flow path of the steam utilization device 4 due to the flow path resistance of the steam utilization device 4. In addition, an electrochemical reaction occurs in the steam utilization device 4 in which water vapor W2 is decomposed into hydrogen and oxygen, and the pressure of water vapor W2 decreases accordingly. The temperature of the electrolytic cell changes due to the electrochemical reaction in the steam utilization device 4. In this case, if the configuration is such that heat exchange occurs between at least one of the oxygen and hydrogen produced downstream of the electrolytic cell and the water vapor W2 upstream of the electrolytic cell as a result of the temperature change of the electrolytic cell, the temperature of water vapor W2 will change. Therefore, there is a correlation between the pressure loss of water vapor W2 and the temperature of the water vapor W2 and the temperature of the electrolytic cell, and this correlation may be used to detect (estimate) the pressure loss of water vapor W2.

[0037] Furthermore, there is a correlation between the temperature of the gas phase 23 in the evaporator 2 and the temperature of the water vapor W2 and the temperature of the electrolytic cell. Therefore, there is also a correlation between the pressure loss of water vapor W2 and the temperature of the gas phase 23 in the evaporator 2, and this correlation can be used to detect (estimate) the pressure loss of water vapor W2.

[0038] (Control Unit 6) As shown in Figure 1, the control unit 6 in this embodiment is formed in the control device. The control unit 6 is configured to change the opening degree of a flow resistance adjustment valve 51 that can change the flow rate of water vapor W2 in order to suppress fluctuations in the mass flow rate of water vapor W2 from the evaporator 2 to the steam utilization device 4. The mass flow rate of water vapor W2 from the evaporator 2 to the steam utilization device 4 is affected by the mass flow rate of water W1 from the transfer device 3 to the evaporator 2.

[0039] Furthermore, there is a correlation between the mass flow rate of steam W2 flowing through the steam utilization device 4 and the pressure loss generated in the steam W2 flowing through the steam utilization device 4, and there is a correlation between the mass flow rate of water W1 flowing through the flow resistance control valve 51 and the pressure loss generated in the water W1 flowing through the flow resistance control valve 51. In other words, when the mass flow rate of steam W2 flowing through the steam utilization device 4 increases, the pressure loss generated in the steam W2 flowing through the steam utilization device 4 increases. Also, when the mass flow rate of water W1 flowing through the flow resistance control valve 51 increases, the pressure loss generated in the water W1 flowing through the flow resistance control valve 51 increases.

[0040] Therefore, the control unit 6 utilizes the relationship between the pressure loss in the steam W2 flowing through the steam utilization device 4 and the pressure loss in the water W1 flowing through the flow resistance control valve 51 to change the mass flow rate of the water W1 flowing through the flow resistance control valve 51, thereby suppressing fluctuations in the mass flow rate of the steam W2 flowing through the steam utilization device 4. More specifically, the control unit 6 in this embodiment is configured to increase the opening degree of the flow resistance control valve 51 as the ratio of the pressure loss of water W1 to the pressure loss of steam W2 increases. Furthermore, the control unit 6 is configured to change the opening degree of the flow resistance control valve 51 so that the ratio of the pressure loss of steam W2 to the pressure loss of water W1 approaches a constant value.

[0041] The mass flow rate of the water W1 flowing through the flow path resistance adjustment valve 51 is m L , and the mass flow rate of the steam W2 flowing through the steam utilization device 4 is m G , the pressure loss generated in the water W1 flowing through the flow path resistance adjustment valve 51 is ΔP L , and the pressure loss generated in the steam W2 flowing through the steam utilization device 4 is ΔP G , and when α and β are coefficients, generally there is the following correlation. That is, ΔP L ∝αm L n , ΔP G ∝βm G n , ΔP L , ΔP G =αm L n :βm G n There is a relationship of. n is shown as a numerical value between 1.5 and 2. In fact, it is considered to have a more complex relationship.

[0042] Therefore, the larger the pressure loss ΔP G of the water W1 with respect to the pressure loss ΔP L of the steam W2, the control unit 6 increases the opening degree K of the flow path resistance adjustment valve 51, and it is considered that the change in the mass flow rate of the steam W2 can be suppressed. On the other hand, the smaller the pressure loss ΔP G of the water W1 with respect to the pressure loss ΔP L of the steam W2, the control unit 6 decreases the opening degree K of the flow path resistance adjustment valve 51, and it is considered that the change in the mass flow rate of the steam W2 can be suppressed.

[0043] In FIG. 4, the mass flow rate m L of the water W1 flowing through the flow path resistance adjustment valve 51, the pressure loss ΔP L generated in the water W1 flowing through the flow path resistance adjustment valve 51, and the pressure loss ΔP G generated in the steam W2 flowing through the steam utilization device 4 are shown. The pressure loss on the vertical axis is shown as a logarithmic graph. The pressure loss ΔP G of the steam W2 is larger than the pressure loss ΔP L of the water W1. Also, the mass flow rate m of the water W1L When it increases, the pressure loss ΔP of water W1 L and the pressure loss ΔP of water vapor W2 G All of these will increase. The numerical values ​​in the graph in Figure 4 are approximate and units are omitted.

[0044] Figure 5 shows the mass flow rate m of water W1 flowing through the flow resistance control valve 51. L And the pressure loss ΔP that occurs in the steam W2 flowing through the steam utilization device 4. G The pressure loss ΔP that occurs in the water W1 flowing through the flow resistance control valve 51 is due to this. L The ratio (called the pressure loss ratio) ΔP L / ΔP G This shows the relationship with the mass flow rate of water W1 m. L When it increases, the pressure loss ratio ΔP L / ΔP G This increases. The numerical values ​​in the graph in Figure 5 are approximate and units are omitted.

[0045] The diagram is omitted, but the pressure loss ratio ΔP L / ΔP G And, pressure loss ratio ΔP L / ΔP G The control unit 6 may have a map M1 that shows the relationship between the opening degree K of the flow resistance control valve 51 which is changed based on the following. G The pressure loss ΔP that occurs in water W1 is relative to the following: L The ratio can be compared with map M1 to determine the opening degree K of the flow resistance control valve 51. Alternatively, the opening degree K of the flow resistance control valve 51 may be determined in a direction that decreases by a predetermined amount as the target opening degree.

[0046] (Temperature fluctuations in steam utilization device 4) In the steam utilization device 4, the amount of hydrogen produced from steam W2 may fluctuate in a wave-like manner in response to commands from the control devices of various hydrogen-utilizing devices. At this time, the temperature in the steam utilization device 4 fluctuates, and it is difficult to suppress this temperature fluctuation. Furthermore, when the temperature in the steam utilization device 4 fluctuates, the mass flow rate of steam W2 in the steam utilization device 4 also fluctuates. Therefore, in the steam utilization system 1 of this embodiment, the amplitude of the fluctuations in the mass flow rate of steam W2 is reduced by intentionally changing the flow resistance of water W1 on the liquid phase side using the flow resistance adjustment valve 51 in response to fluctuations in the mass flow rate of steam W2 on the gas phase side.

[0047] In the steam utilization system 1, if there is no flow path resistance adjustment valve 51, it is conceivable to change the discharge flow rate of the transfer device 3, such as a pump. However, simply changing the discharge flow rate of the transfer device 3 may actually increase the fluctuation in the mass flow rate of steam W2 due to the pulsation of the pump that constitutes the transfer device 3, making it difficult to suppress fluctuations in the mass flow rate of steam W2.

[0048] It was found that narrowing the flow area of ​​the piping 31 by the flow resistance adjustment valve 51 and increasing the flow resistance of water W1 on the liquid phase side is effective in suppressing fluctuations in the mass flow rate of water vapor W2 in the steam utilization device 4. Also, the pressure loss ratio ΔP L / ΔP G When determining the opening degree K of the flow resistance control valve 51 based on the above, the opening degree of the flow resistance control valve 51 may be set to be a predetermined amount smaller than the target opening degree. This may adjust the flow resistance of the water W1 on the liquid phase side to increase, thereby more effectively suppressing fluctuations in the mass flow rate of water vapor W2.

[0049] (Properties of Steam Utilization System 1) The flow resistance of the steam utilization device 4, which constitutes the steam electrolysis apparatus, is greater than the flow resistance from the outlet of the transfer device 3 to the outlet of the evaporator 2. Furthermore, the pressure loss due to steam W2 in the steam utilization device 4 is greater than the pressure loss due to water W1 and steam W2 from the outlet of the transfer device 3 to the outlet of the evaporator 2. Due to these properties, the steam utilization device 4 is prone to fluctuations in the mass flow rate of steam W2. The steam utilization system 1 of this embodiment effectively suppresses fluctuations in the mass flow rate of steam W2 in the steam utilization device 4, which is prone to such fluctuations in the mass flow rate of steam W2.

[0050] (Control method) An example of a control method for the steam utilization system 1 will be explained with reference to the flowchart in Figure 6. First, the steam utilization system 1 is started (step S101), and a predetermined time is waited until the steam utilization device 4 reaches a steady state in which it generates the required hydrogen (step S102). At this time, the opening degree of the flow resistance control valve 51 is in a predetermined initial state. Next, the pressure loss occurring in the water W1 is detected by the liquid detection unit 52, and the pressure loss occurring in the water vapor W2 is detected by the steam detection unit 53 (step S103).

[0051] Next, the control unit 6 calculates the ratio of the pressure loss of water W1 to the pressure loss of water vapor W2, and this ratio is compared with map M1 to determine the target opening degree of the flow resistance control valve 51 (step S104). Then, the control unit 6 operates the flow resistance control valve 51, and the opening degree of the flow resistance control valve 51 is changed to the target opening degree (step S105). After that, steps S103 to S106 are repeated each time a predetermined amount of time has elapsed (step S106). Furthermore, this control of the opening degree of the flow resistance control valve 51 by the control unit 6 ends when a control stop command is received.

[0052] (Effects and Benefits) This steam utilization system 1 utilizes the relative relationship between the pressure loss of steam W2 and the pressure loss of water W1, and by adjusting the opening degree of a flow resistance adjustment valve 51 that can change the mass flow rate of water W1, it suppresses fluctuations in the mass flow rate of steam W2 in the steam utilization device 4. The reason why fluctuations in the mass flow rate of steam W2 in the steam utilization device 4 can be suppressed more effectively is as follows.

[0053] As shown in Figure 2, when the water vapor W2 in the steam utilization device 4 becomes hot, the mass flow rate of water vapor W2 increases due to the decrease in the density of water vapor W2. At this time, the ratio of the pressure loss of water W1 to the pressure loss of water vapor W2 (pressure loss ratio ΔP) L / ΔP G ) changes in the direction of decreasing. Therefore, the control unit 6 changes the opening of the flow resistance adjustment valve 51 in the direction of decreasing. As a result, the pressure loss ratio ΔP L / ΔP G The adjustment is made in a direction that increases the value. As a result, if the mass flow rate of steam W2 in the steam utilization device 4 increases, the adjustment is made so that the mass flow rate of steam W2 in the steam utilization device 4 decreases. The opening degree of the flow path resistance adjustment valve 51 by the control unit 6 is then adjusted so that the ratio of the pressure loss of water W1 to the pressure loss of steam W2 approaches a constant value.

[0054] When the water vapor W2 in the steam utilization device 4 becomes cold, the mass flow rate of water vapor W2 decreases due to the increase in the density of water vapor W2. At this time, the pressure loss ratio ΔP L / ΔP G The pressure loss ratio ΔP changes in the direction of increasing. Therefore, the control unit 6 changes the opening of the flow resistance adjustment valve 51 in the direction of increasing it. As a result, the pressure loss ratio ΔP L / ΔP G The pressure is adjusted to decrease. As a result, if the mass flow rate of steam W2 in the steam utilization device 4 decreases, the pressure is adjusted to increase the mass flow rate of steam W2 in the steam utilization device 4. The opening degree of the flow path resistance adjustment valve 51 by the control unit 6 is then adjusted so that the ratio of the pressure loss of water W1 to the pressure loss of steam W2 approaches a constant value.

[0055] Thus, according to the steam utilization system 1 of this embodiment, fluctuations in the mass flow rate of steam W2 in the steam utilization device 4 can be suppressed. Furthermore, by suppressing fluctuations in the mass flow rate of steam W2, measures such as extra-increasing the mass flow rate of steam W2 to prevent a shortage of steam W2 when the mass flow rate of steam W2 fluctuates in a decreasing direction become unnecessary.

[0056] <Embodiment 2> This embodiment, as shown in Figure 7, describes a case in Embodiment 1 where the steam utilization system 1 is equipped with a flow meter 54 for measuring the flow rate of water W1 flowing from the flow resistance control valve 51 to the evaporator 2. The flow meter 54 is located in the piping 31 connecting the transfer device 3 to the evaporator 2, downstream of the flow of water W1 from the location of the flow resistance control valve 51. The flow meter 54 in this embodiment is a mass flow meter that measures the mass flow rate of water W1.

[0057] The mass flow rate of water W1 measured by the flow meter 54 is configured to be transmitted to the control unit 6. Since the temperature of water W1 transported by the transport device 3 does not change significantly and the density of water W1 changes only slightly, the flow meter 54 may also be a volumetric flow meter that measures volumetric flow rate.

[0058] The flow meter 54 has a predetermined flow resistance in order to measure the mass flow rate of water W1. The liquid detection unit 52 in this embodiment is configured to detect the pressure loss of water W1 by the differential pressure of water W1 on the upstream and downstream sides of the flow meter 54. More specifically, pressure gauges 521 and 522 are placed on the upstream and downstream sides of the flow meter 54, with the flow meter 54 in between. The differential pressure between the pressure measured by pressure gauge 521, which is located upstream of the flow meter 54, and the pressure measured by pressure gauge 522, which is located downstream of the flow meter 54, is detected by the liquid detection unit 52 as the pressure loss of water W1.

[0059] The liquid detection unit 52 may also detect the pressure loss of water W1 by the differential pressure of water W1 between the upstream side of the flow resistance regulating valve 51 and the downstream side of the flow meter 54. In this case, pressure gauges 521 and 522 are placed between the flow resistance regulating valve 51 and the flow meter 54, with the flow resistance regulating valve 51 and the flow meter 54 in between. The differential pressure between the pressure measured by pressure gauge 521, which is located upstream of the flow resistance regulating valve 51, and the pressure measured by pressure gauge 522, which is located downstream of the flow meter 54, is detected by the liquid detection unit 52 as the pressure loss of water W1.

[0060] In this configuration, the control unit 6 is configured to change the opening degree of the flow resistance control valve 51 while maintaining the mass flow rate of water W1 measured by the flow meter 54 at the target flow rate. More specifically, when the opening degree of the flow resistance control valve 51 is reduced, the mass flow rate of water W1 decreases, and it is conceivable that the mass flow rate of steam W2 required by the steam utilization device 4 may not be secured.

[0061] Therefore, in this embodiment, when reducing the opening degree of the flow resistance control valve 51, the opening degree of the flow resistance control valve 51 is reduced within a range in which the mass flow rate of water W1 measured by the flow meter 54 is equal to or greater than the target flow rate. As a result, when using the flow resistance control valve 51, the required mass flow rate of water vapor W2 can always be appropriately secured in the steam utilization device 4.

[0062] The flow meter 54 may be used to measure the flow rate of water vapor W2 in the steam utilization device 4 or the evaporator 2.

[0063] The other configurations, effects, etc. of the steam utilization system 1 in this embodiment are the same as those of Embodiment 1. In this embodiment as well, the components indicated by the same reference numerals as those shown in Embodiment 1 are the same as those of Embodiment 1.

[0064] <Embodiment 3> This embodiment, as shown in Figure 8, describes a case in Embodiment 1 where the transfer device 3 is composed of a non-positive displacement pump and the discharge flow rate of the pump is changed as appropriate. The transfer device 3 in this embodiment is composed of a non-positive displacement pump such as a centrifugal pump, rotary pump, or propeller pump. Due to its structure, the discharge flow rate of a non-positive displacement pump may not be constant. Furthermore, it is conceivable that the mass flow rate of water W1 supplied to the evaporator 2 may be insufficient due to the adjustment of the opening degree of the flow resistance adjustment valve 51.

[0065] Therefore, the control unit 6 in this embodiment is configured to change the discharge flow rate of the pump so that the flow rate of water W1 measured by the flow meter 54 is maintained at the target flow rate when the opening degree of the flow resistance control valve 51 is changed. In particular, when the opening degree of the flow resistance control valve 51 is reduced, the discharge flow rate of the pump as a transfer device 3 may be increased so that the flow rate of water W1 measured by the flow meter 54 is equal to or greater than the target flow rate. As a result, when using the flow resistance control valve 51, the required mass flow rate of water vapor W2 can always be appropriately secured in the steam utilization device 4.

[0066] The other configurations, effects, etc., of the steam utilization system 1 in this embodiment are the same as those in Embodiments 1 and 2. In this embodiment as well, the components indicated by the same reference numerals as those shown in Embodiments 1 and 2 are the same as those in Embodiments 1 and 2.

[0067] <Embodiment 4> This embodiment, as shown in Figure 9, describes a steam utilization system 1 that, in the first embodiment, uses a flow meter 54 to measure the flow rate of water W1 instead of a liquid detection unit 52 and a steam detection unit 53. This embodiment of the steam utilization system 1 does not have a liquid detection unit 52 and a steam detection unit 53, but has a flow meter 54 that measures the flow rate of water W1 flowing from the flow resistance control valve 51 to the evaporator 2. The flow meter 54 is located in the piping 31 connecting the transfer device 3 to the evaporator 2, downstream of the flow of water W1 from the location of the flow resistance control valve 51.

[0068] In this embodiment, the control unit 6 is configured to adjust the opening degree of the flow resistance regulating valve 51 based on the flow rate of water W1 measured by the flow meter 54. More specifically, the control unit 6 is configured to decrease the opening degree of the flow resistance regulating valve 51 as the flow rate of water W1 measured by the flow meter 54 increases. The control unit 6 is configured to change the opening degree of the flow resistance regulating valve 51 so that the flow rate of water W1 approaches a constant value.

[0069] As shown in Embodiment 1, the pressure loss ΔP of water vapor W2 G Pressure loss ΔP of water W1 L The proportion ΔP L / ΔP G And the mass flow rate m of water W1 flowing through the flow resistance control valve 51 L There is a correlation between the two. Therefore, in this embodiment, the flow rate of water W1 flowing through the flow resistance regulating valve 51 is measured by the flow meter 54, and the control unit 6 adjusts the opening degree of the flow resistance regulating valve 51 based on the flow rate of water W1 measured by the flow meter 54.

[0070] Although not shown in the diagram, the control unit 6 controls the mass flow rate of water m L And, the mass flow rate of water m L The control unit 6 may have a map M2 that shows the relationship between the opening degree K of the flow resistance control valve 51 which is changed based on the following. L The opening degree K of the flow resistance control valve 51 may be determined by comparing it with map M2. Alternatively, the opening degree K of the flow resistance control valve 51 may be determined in a direction that is reduced by a predetermined amount as the target opening degree.

[0071] The steam utilization system 1 in this embodiment suppresses fluctuations in the mass flow rate of steam W2 in the steam utilization device 4 by adjusting the opening degree of the flow resistance adjustment valve 51 using the flow rate of water W1 measured by the flow meter 54. The reason why fluctuations in the mass flow rate of steam in the steam utilization device 4 can be suppressed more effectively is as follows.

[0072] When the water vapor W2 in the steam utilization device 4 reaches a high temperature, the density of the water vapor W2 decreases, causing the mass flow rates of water W1 and water vapor W2 to increase. At this time, the flow rate of water W1 measured by the flow meter 54 increases. Therefore, the control unit 6 changes the opening of the flow resistance adjustment valve 51 to a smaller degree. As a result, the flow rate of water W1 in the piping 31 decreases. Consequently, if the mass flow rate of water vapor W2 in the steam utilization device 4 increases, the system is adjusted to decrease the mass flow rate of water vapor W2 in the steam utilization device 4.

[0073] When the steam in the steam utilization device 4 becomes cold, the density of water vapor W2 increases, causing a decrease in the mass flow rates of water W1 and water vapor W2. At this time, the flow rate of water W1 measured by the flow meter 54 decreases. Therefore, the control unit 6 changes the opening of the flow resistance adjustment valve 51 to a larger degree. As a result, the flow rate of water W1 in the piping 31 increases. Consequently, if the mass flow rate of water vapor W2 in the steam utilization device 4 decreases, the system is adjusted to increase the mass flow rate of water vapor W2 in the steam utilization device 4.

[0074] In this embodiment as well, as shown in Embodiment 3, the transfer device 3 may be configured with a non-positive displacement pump, and the discharge flow rate of the pump may be changed as appropriate. In this case, when the control unit 6 changes the opening degree of the flow resistance control valve 51, it changes the discharge flow rate of the pump so that the flow rate of water W1 measured by the flow meter 54 is maintained at the target flow rate. In particular, when the opening degree of the flow resistance control valve 51 is reduced, the discharge flow rate of the pump as the transfer device 3 may be increased so that the flow rate of water W1 measured by the flow meter 54 is equal to or greater than the target flow rate. This makes it possible to always appropriately secure the required mass flow rate of water vapor W2 in the steam utilization device 4 when using the flow resistance control valve 51.

[0075] The other configurations, effects, etc., of the steam utilization system 1 in this embodiment are the same as those in Embodiments 1 to 3. In this embodiment as well, the components indicated by the same reference numerals as those shown in Embodiments 1 to 3 are the same as those in Embodiments 1 to 3.

[0076] The present invention is not limited to the embodiments described herein, and further different embodiments can be constructed without departing from the spirit of the invention. Furthermore, the present invention includes various modifications, modifications within the equivalent range, etc. Moreover, various combinations and forms of components conceivable from the present invention are also included in the technical concept of the present invention. [Explanation of symbols]

[0077] 1. Steam utilization system 2 Evaporator 3 Transfer device 4. Steam utilization equipment 51 Flow resistance regulating valve 52 Liquid detection unit 53 Steam detection unit 54 Flow meter 6 Control Unit

Claims

1. An evaporator (2) that evaporates a liquid to generate steam, A transfer device (3) for transferring the liquid to the evaporator, The steam utilization device (4) uses the steam sent from the evaporator, and the steam flow resistance of the steam is provided. A flow resistance adjustment valve (51) is provided in the piping (31) between the transfer device and the evaporator, for adjusting the flow resistance of the liquid in the piping. A liquid detection unit (52) that detects the pressure loss of the liquid in any of the transfer device, the flow path resistance adjustment valve, and the evaporator, A steam detection unit (53) that detects the pressure loss of the steam in either the evaporator or the steam utilization device, The system includes a control unit (6) that adjusts the opening degree of the flow resistance adjustment valve based on the relative relationship between the pressure loss of the steam and the pressure loss of the liquid, The control unit is configured to increase the opening of the flow resistance adjustment valve as the ratio of the liquid pressure loss to the steam pressure loss increases. The steam detection unit detects the pressure loss of the steam based on the differential pressure of the steam between the upstream and downstream sides of the steam utilization device, in a steam utilization system (1).

2. The steam utilization system according to claim 1, wherein the liquid detection unit detects the pressure loss of the liquid by the differential pressure of the liquid on the upstream and downstream sides of the flow resistance adjustment valve.

3. The system further includes a flow meter (54) for measuring the flow rate of the liquid flowing from the flow resistance adjustment valve to the evaporator, The steam utilization system according to claim 1, wherein the liquid detection unit detects the pressure loss of the liquid based on the differential pressure of the liquid on the upstream and downstream sides of the flow meter.

4. The steam utilization system further comprises a flow meter (54) for measuring the flow rate of the liquid or steam flowing through any part of the steam utilization system, The steam utilization system according to claim 1 or 2, wherein the control unit is configured to change the opening degree of the flow resistance adjustment valve while the flow rate of the liquid or steam measured by the flow meter is maintained at a target flow rate.

5. The steam utilization system further comprises a flow meter (54) for measuring the flow rate of the liquid or steam flowing through any part of the steam utilization system, The transfer device is composed of a non-positive displacement pump, The steam utilization system according to claim 1 or 2, wherein the control unit is configured to change the discharge flow rate of the pump so that the flow rate of the liquid or steam measured by the flow meter is maintained at a target flow rate when the opening degree of the flow resistance adjustment valve is changed.

6. The aforementioned liquid is composed of water, The steam utilization system according to claim 1 or 2, wherein the steam utilization device constitutes a water electrolysis device that utilizes water vapor as steam.

7. The steam utilization system according to claim 6, wherein the water electrolysis apparatus is a steam electrolysis apparatus that decomposes the steam to produce hydrogen.

8. The steam utilization system according to claim 1 or 2, wherein the flow resistance of the steam utilization device is greater than the flow resistance from the outlet of the transfer device to the outlet of the evaporator.

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