Steam power-generating plant

Abstract

To provide a steam power-generating plant capable of improving system efficiency of the steam power-generating plant.SOLUTION: A steam power-generating plant 1 includes: a first steam pipe 41 connecting a boiler 21 and a steam turbine 22; a second steam pipe 44 branching from the first steam pipe 41 and supplying steam generated by the boiler 21 as a heat medium to a heat exchanger 32 of a hydrogen production system 3; and a return piping 46 supplying the heat medium after passing through the heat exchanger 32 to a condensate tank 25 or a deaerator 26, wherein the return piping 46 is provided with a changeover valve Vc that switches a supply destination of the heat medium after passing through the heat exchanger 32 between the condensate tank 25 and the deaerator 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to steam power plants. [Background technology]

[0002] Conventionally, steam power plants have been known that have a boiler steam turbine system in which steam is generated in a boiler and used to rotate a steam turbine to generate electricity. The boiler steam turbine system has a condenser that cools the exhaust steam from the steam turbine. If the condenser is air-cooled, when the outside air temperature becomes too high, such as in summer, the temperature of the air used to cool the exhaust steam rises, making it impossible for the condenser to sufficiently cool the exhaust steam. In Non-Patent Document 1, the temperature of the air inlet of the condenser is lowered by spraying a cooling mist or sprinkling water onto the air inlet. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] ELFLOW BV, How to improve air cooler vacuum steam condensers performance in the field, Technical paper ID 309 for POWER-GEN EUROPE 2012 Summary of the Invention [Problem to be solved by the invention]

[0004] It is expected that temperatures will continue to rise due to global warming. The configuration of Non-Patent Document 1 may not be able to sufficiently lower the temperature at the condenser's air inlet. If the condenser cannot sufficiently cool the exhaust steam, the turbine back pressure increases, reducing turbine efficiency. As a result, the amount of power generated by the steam turbine decreases, and excess steam that cannot be processed by the steam turbine is generated. In conventional boiler steam turbine systems, excess steam that cannot be processed by the steam turbine is supplied to the condenser via a turbine bypass. Alternatively, the amount of steam generated by the boiler is reduced to suppress the generation of excess steam. In either case, the system efficiency of the steam power plant decreases.

[0005] Hydrogen production systems that use renewable energy to produce hydrogen are also known, but the challenge for such systems is finding a source of thermal energy for producing hydrogen.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steam power plant capable of improving system efficiency. [Means for solving the problem]

[0007] A steam power plant according to a first aspect of the present invention is a steam power plant including a boiler steam turbine system and a hydrogen production system, wherein the boiler steam turbine system includes a boiler that generates steam, a steam turbine that is rotated by the steam generated in the boiler, a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water, an exhaust condensate tank that stores the drain water condensed in the condenser under negative pressure, a condensate tank that stores the drain water discharged from the exhaust condensate tank under atmospheric pressure, and a deaerator that deaerates feed water supplied from the condensate tank, and the hydrogen production system includes The system has a hydrogen production device that produces hydrogen from a raw material and a heat exchanger that heats the raw material by exchanging heat between the raw material and a heat medium, and the steam power plant has a first steam pipe that connects the boiler and the steam turbine, a second steam pipe that branches off from the first steam pipe and supplies steam generated in the boiler to the heat exchanger as the heat medium, and a return pipe that supplies the heat medium after passing through the heat exchanger to the condensate tank or the deaerator, and the return pipe is provided with a switching valve that switches the supply destination of the heat medium after passing through the heat exchanger between the condensate tank and the deaerator.

[0008] A steam power plant according to a second aspect of the present invention is a steam power plant according to the first aspect, wherein the switching valve comprises a valve body having an internal space and having an inlet, a first outlet, and a second outlet communicating with the internal space, and a float arranged in the internal space and blocking the first outlet in an openable and closable manner, and the return pipe comprises a first pipe connecting the heat exchanger and the inlet, a second pipe connecting the first outlet and the condensate tank, and a third pipe connecting the second outlet and the deaerator, and when the heat medium supplied to the inlet through the first pipe is liquid, the float is floated up by the liquid heat medium stored in the internal space, thereby opening the first outlet, and when the heat medium supplied to the inlet through the first pipe is gaseous, the float is pressed against the first outlet by the vapor pressure in the internal space, thereby blocking the first outlet.

[0009] A steam power plant according to a third aspect of the present invention is the second aspect, wherein the switching valve has a lid that closes the second outlet in an openable and closable manner, and when the heat medium supplied to the inlet via the first piping is gaseous, the lid is pushed up by the steam pressure in the internal space, opening the second outlet.

[0010] The steam power plant according to a fourth aspect of the present invention is the steam power plant of the first aspect, further comprising a valve control unit that controls the switching valve based on a temperature of the heat medium after passing through the heat exchanger.

[0011] A steam power plant according to a fifth aspect of the present invention is the steam power plant of the fourth aspect, wherein the switching valve is a three-way valve having an inlet, a first outlet, and a second outlet, and the return pipe has a first pipe connecting the heat exchanger and the inlet, a second pipe connecting the first outlet and the condensate tank, and a third pipe connecting the second outlet and the deaerator, and when T3 is the temperature of the heat medium after passing through the heat exchanger and Tc is the temperature of the feedwater in the condensate tank, the valve control unit controls the switching valve to open the first outlet and close the second outlet when T3≦Tc+30, and controls the switching valve to close the first outlet and open the second outlet when T3>Tc+30.

[0012] A steam power plant according to a sixth aspect of the present invention is any one of the first to fifth aspects, wherein the hydrogen production system further includes a hydrogen production control unit that controls the amount of hydrogen produced in the hydrogen production device based on the temperature of the heat medium after passing through the heat exchanger.

[0013] A steam power plant according to a seventh aspect of the present invention is any one of the first to sixth aspects, wherein a first flow control valve is provided on the first steam pipe downstream of the branching point with the second steam pipe, for adjusting the amount of steam supplied to the steam turbine based on the pressure in the exhaust condensate tank.

[0014] An eighth aspect of the present invention is a steam power plant according to the seventh aspect, wherein the second steam pipe is provided with a second flow control valve that adjusts the amount of steam flowing through the second steam pipe, and the second flow control valve is in an open state when the amount of steam generated in the boiler is greater than the amount of steam supplied to the steam turbine.

[0015] A steam power plant according to a ninth aspect of the present invention is the eighth aspect, wherein when the amount of steam generated in the boiler is q0 and the amount of steam supplied to the steam turbine is q1, the second flow control valve controls the opening degree of the second flow control valve so that the amount of steam q2 flowing through the second steam pipe satisfies q2 = q0 - q1.

[0016] A steam power plant according to a tenth aspect of the present invention is a steam power plant including a boiler steam turbine system and a hydrogen production system, wherein the boiler steam turbine system includes a boiler that generates steam, a steam turbine that is rotated by the steam generated in the boiler, a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water, an exhaust condensate tank that stores the drain water condensed in the condenser under negative pressure, a condensate tank that stores the drain water discharged from the exhaust condensate tank under atmospheric pressure, and a deaerator that deaerates feed water supplied from the condensate tank, and the hydrogen production system includes a water condenser that produces hydrogen from a raw material, a boiler steam turbine system that generates steam, a steam turbine that is rotated by the steam generated in the boiler, a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water, an exhaust condensate tank that stores the drain water condensed in the condenser under negative pressure, a condensate tank that stores the drain water discharged from the exhaust condensate tank under atmospheric pressure, and a deaerator that deaerates feed water supplied from the condensate tank, and the hydrogen production control unit controls the amount of hydrogen produced by the hydrogen production device so as to reduce the difference between the temperature of the heat medium after passing through the heat exchanger and the temperature of the feedwater in the condensate tank.

[0017] A steam power plant according to an eleventh aspect of the present invention is a steam power plant including a boiler steam turbine system and a hydrogen production system, wherein the boiler steam turbine system includes a boiler that generates steam, a steam turbine that is rotated by the steam generated in the boiler, a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water, an exhaust condensate tank that stores the drain water condensed in the condenser under negative pressure, a condensate tank that stores the drain water discharged from the exhaust condensate tank under atmospheric pressure, and a deaerator that deaerates feed water supplied from the condensate tank, and the hydrogen production system includes a boiler that generates steam, a steam turbine that is rotated by the steam generated in the boiler, a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water, an exhaust condensate tank that stores the drain water discharged from the exhaust condensate tank under atmospheric pressure, and a deaerator that deaerates feed water supplied from the condensate tank, and the hydrogen production control unit controls the amount of hydrogen produced in the hydrogen production device so as to reduce the difference between the temperature of the heat medium after passing through the heat exchanger and the temperature of the feedwater in the deaerator.

[0018] A steam power plant according to a twelfth aspect of the present invention is the steam power plant of the tenth or eleventh aspect, wherein a first flow control valve is provided on the first steam pipe downstream of the branching point with the second steam pipe, for adjusting the amount of steam supplied to the steam turbine based on the pressure in the exhaust condensate tank.

[0019] A steam power plant according to a thirteenth aspect of the present invention is any one of the first to twelfth aspects, wherein the hydrogen production device is connected to a renewable energy power generation facility, and hydrogen is produced by any one of high-temperature steam electrolysis, alkaline water electrolysis, and solid polymer membrane water electrolysis using electric power supplied from the renewable energy power generation facility.

[0020] A steam power plant according to a fourteenth aspect of the present invention is the steam power plant according to any one of the first to thirteenth aspects, wherein the hydrogen production device has an electrochemical cell that produces hydrogen using external electric power.

[0021] A fifteenth aspect of the present invention relates to a steam power plant according to the fourteenth aspect, wherein the hydrogen production system further comprises a hydrogen storage tank connected to the hydrogen production device and storing hydrogen produced by the hydrogen production device, and the electrochemical cell is capable of generating electricity using hydrogen in the hydrogen storage tank. [Effects of the Invention]

[0022] According to one aspect of the present invention, the system efficiency of a steam power plant can be improved. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing the configuration of a steam power plant according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the relationship between the amount of power generation and the air temperature in the steam power generation plant according to the first embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the switching valve according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a steam power plant according to a second embodiment. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of a steam power plant according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0025] First Embodiment 1 is a schematic diagram showing the configuration of a steam power plant 1 according to a first embodiment. As shown in FIG. 1, the steam power plant 1 includes a boiler steam turbine system 2 and a hydrogen production system 3.

[0026] The hydrogen production system 3 includes a hydrogen production device 31, a heat exchanger 32, a hydrogen storage tank 33, and a hydrogen production control unit 34. The hydrogen production system 3 is connected to a renewable energy power generation facility 4. The renewable energy power generation facility 4 generates electricity using, for example, solar power generation, wind power generation, geothermal power generation, wave power generation, or tidal power generation. The hydrogen production device 31 produces hydrogen from raw materials such as water using the electricity supplied from the renewable energy power generation facility 4. The hydrogen storage tank 33 is connected to the hydrogen production device 31 and stores the hydrogen produced by the hydrogen production device 31 in a liquid or gas state. The hydrogen stored in the hydrogen storage tank 33 is used, for example, for power generation in emergencies or during regular inspections of the steam power plant 1.

[0027] The hydrogen production device 31 has an electrolytic cell 31a (electrochemical cell). An electrochemical cell is a device that produces hydrogen from water using an electrochemical reaction. The hydrogen production device 31 produces hydrogen, for example, by high-temperature steam electrolysis. In this case, a solid oxide cell that uses a solid oxide such as yttria-stabilized zirconia as an electrolyte is used as the electrolytic cell 31a. The hydrogen production device 31 produces hydrogen by electrolyzing high-temperature steam using the electrolytic cell 31a, using power supplied from the renewable energy power generation facility 4. A proton-conductive ceramic fuel cell may be used as the electrolytic cell 31a.

[0028] In high-temperature steam electrolysis, water or steam as a raw material is heated to generate high-temperature steam, which is then supplied to a hydrogen production device 31. The hydrogen production system 3 generates Joule heat using electricity supplied from a renewable energy power generation facility 4, and can generate high-temperature steam by heating the raw material with the Joule heat. The hydrogen production system 3 can also generate high-temperature steam by exchanging heat between the raw material and a heat medium in a heat exchanger 32. As will be described in detail later, the heat exchanger 32 uses steam generated in a boiler 21 of the boiler steam turbine system 2 as a heat medium.

[0029] The hydrogen production device 31 is configured to be capable of electrochemically reversible operation. Specifically, the hydrogen production device 31 can generate electricity by using the electrolytic cell 31a as a fuel cell using hydrogen stored in the hydrogen storage tank 33. That is, in the hydrogen production system 3, hydrogen production and power generation using hydrogen can be performed using a single electrolytic cell 31a. Note that the hydrogen production system 3 may also be provided with a fuel cell system that generates power using hydrogen stored in the hydrogen storage tank 33.

[0030] The hydrogen production device 31 may also produce hydrogen by alkaline water electrolysis or polymer electrolyte membrane (PEM) water electrolysis. In alkaline water electrolysis, an anode electrode and a cathode electrode are placed in an electrolytic cell containing an aqueous potassium hydroxide solution as an electrolyte, and hydrogen is produced by passing a current through the electrodes. In alkaline water electrolysis, a membrane made of a resin containing metal particles or a solid polymer membrane is used as the electrochemical cell. In solid polymer membrane water electrolysis, hydrogen is produced by electrolyzing water using an electrolytic cell in which electrodes are placed on both sides of a solid polymer membrane as an electrolyte. In solid polymer membrane water electrolysis, a solid polymer membrane made of a fluororesin is used as the electrochemical cell. In these methods, the hydrogen production device 31 can also produce hydrogen using electricity supplied from the renewable energy power generation facility 4 or thermal energy generated by heat exchange in the heat exchanger 32.

[0031] The hydrogen production control unit 34 controls the hydrogen production device 31. Some or all of the functional units of the hydrogen production control unit 34 are realized as software by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit having a non-volatile storage medium (non-transitory storage medium). The program may be recorded on a computer-readable storage medium. Examples of computer-readable storage media include portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs (Compact Disc Read Only Memory), and non-transitory storage media such as hard disks built into a computer system.

[0032] The boiler steam turbine system 2 is a steam power generation system that directly uses steam to rotate a turbine. The boiler steam turbine system 2 mainly comprises a boiler 21, a steam turbine 22, a condenser 23, an exhaust condensate tank 24, a condensate tank 25, and a deaerator 26. In the boiler steam turbine system 2, steam is generated in the boiler 21, and the steam is used to rotate the steam turbine 22 and generate electricity. The condenser 23 condenses the exhaust steam discharged from the steam turbine 22 to produce drain water. The exhaust condensate tank 24 stores the drain water condensed in the condenser 23 under negative pressure. The drain water in the exhaust condensate tank 24 is sent to the condensate tank 25 by the exhaust condensate pump EP. The condensate tank 25 stores the drain water discharged from the exhaust condensate tank 24 under atmospheric pressure. The feed water from the condensate tank 25 is supplied to the deaerator 26 by the deaerator feed pump DP. The deaerator 26 deaerates and preheats the feedwater supplied from the condensate tank 25 to produce boiler feedwater that is supplied to the boiler 21. The boiler feedwater is pressurized by a boiler feedwater pump BP and supplied to the boiler 21. A binary power generation system having a similar system configuration is also considered to fall under the category of this steam turbine system 2.

[0033] Exhaust gas condensate tank 24 is provided with a first pressure sensor 24a that detects the pressure Pe within exhaust gas condensate tank 24, and a first temperature sensor 24b that detects the temperature Te of drain water within exhaust gas condensate tank 24. Condensate tank 25 is provided with a second pressure sensor 25a that detects the pressure Pc within condensate tank 25, and a second temperature sensor 25b that detects the temperature Tc of feed water within condensate tank 25. Deaerator 26 is provided with a third pressure sensor 26a that detects the pressure Pd within deaerator 26, and a third temperature sensor 26b that detects the temperature Td of feed water within deaerator 26.

[0034] The boiler 21 and the steam turbine 22 are connected by a first steam pipe 41. Steam generated in the boiler 21 is supplied to the steam turbine 22 through the first steam pipe 41. The boiler steam turbine system 2 also has a turbine bypass 45 that branches off from the first steam pipe 41 and forcibly cools the steam generated in the boiler 21 and supplies it to the condenser 23. The steam power plant 1 also has a second steam pipe 44 that branches off from the first steam pipe 41 and supplies the steam generated in the boiler 21 to the heat exchanger 32 as a heat medium.

[0035] The first steam pipe 41 has an upstream pipe 42 located upstream of the branching position with the second steam pipe 44, and a downstream pipe 43 located downstream of the branching position with the second steam pipe 44. The downstream pipe 43 is provided with a first flow rate control valve V1 that adjusts the amount of steam supplied to the steam turbine 22. The second steam pipe 44 is provided with a second flow rate control valve V2 that adjusts the amount of steam flowing through the second steam pipe 44. The turbine bypass 45 is provided with a bypass flow rate control valve V3 that adjusts the amount of steam flowing through the turbine bypass 45.

[0036] The upstream piping 42 is provided with a first flow meter 42a that detects the amount of steam q0 generated in the boiler 21, and a fourth pressure sensor 42b that detects the pressure P0 in the upstream piping 42. The downstream piping 43 is provided with a second flow meter 43a that detects the amount of steam q1 supplied to the steam turbine 22, and a fifth pressure sensor 43b that detects the pressure P1 in the downstream piping 43. The second steam pipe 44 is provided with a third flow meter 44a that detects the amount of steam q2 flowing through the second steam pipe 44, and a sixth pressure sensor 44b that detects the pressure P2 in the second steam pipe 44.

[0037] The boiler steam turbine system 2 includes a valve control unit 27 that controls a first flow control valve V1, a second flow control valve V2, and a bypass flow control valve V3. Detection results from pressure sensors 24a, 25a, 26a, 42b, 43b, and 44b, temperature sensors 24b, 25b, and 26b, and flow meters 42a, 43a, and 44a are input to the valve control unit 27. The valve control unit 27 controls the first flow control valve V1, the second flow control valve V2, and the bypass flow control valve V3 based on these detection results.

[0038] Some or all of the functional units of the valve control unit 27 are realized as software by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit having a non-volatile storage medium (non-transitory storage medium). The program may be recorded on a computer-readable storage medium. Examples of computer-readable storage media include portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs (Compact Disc Read Only Memory), and non-transitory storage devices such as hard disks built into a computer system.

[0039] The condenser 23 is an air-cooled condenser that uses air to cool the exhaust steam from the steam turbine 22. The condenser 23 has a cooling fan 23a that generates a current of cooling air. The condenser 23 controls the rotation speed of the cooling fan 23a based on the temperature Te of the drain water in the exhaust condensate tank 24.

[0040] The cooling capacity of the condenser 23 is determined by the outside air temperature and the rotation speed of the cooling fan 23a. When the outside air temperature is high, the rotation speed of the cooling fan 23a is increased to increase the amount of cooling air, thereby increasing the cooling capacity of the condenser 23. However, because there is an upper limit (maximum rotation speed) to the rotation speed of the cooling fan 23a, if the outside air temperature becomes too high, such as in summer, the condenser 23 cannot sufficiently cool the exhaust steam, and the temperature Te of the drain water in the exhaust condensate tank 24 rises.

[0041] When the temperature Te of the drain water in the exhaust gas condensate tank 24 rises, the pressure Pe in the exhaust gas condensate tank 24 also rises. Here, the turbine efficiency increases as the difference between the pressure P1 in the downstream piping 43 and the pressure Pe (turbine back pressure) in the exhaust gas condensate tank 24 increases. Therefore, when the pressure Pe in the exhaust gas condensate tank 24 rises, the turbine efficiency decreases, and the amount of power generated in the steam turbine 22 decreases.

[0042] The valve control unit 27 controls the opening degree of the first flow control valve V1 based on the pressure P1 in the downstream pipe 43 and the pressure Pe in the exhaust condensate tank 24 so that the amount of power generation in the steam turbine 22 is maximized. Specifically, the power generation amount Psg in the steam turbine 22 is expressed by the following equation (1): q1 is the amount of steam supplied to the steam turbine 22, hin is the enthalpy of steam at the inlet of the steam turbine, hout is the enthalpy of steam at the outlet of the steam turbine, and η is the efficiency. Psg=q1×(hin-hout)×η ···(1) The valve control unit 27 determines the steam flow rate q1 when the power generation amount Psg in the steam turbine 22 is at a maximum. The valve control unit 27 controls the opening degree of the first flow control valve V1 so that the amount of steam supplied to the steam turbine 22 becomes the steam flow rate q1.

[0043] The valve control unit 27 controls the second flow rate control valve V2 to be in an open state when the amount of steam q0 generated in the boiler 21 is greater than the amount of steam q1 supplied to the steam turbine 22. At this time, the valve control unit 27 controls the opening degree of the second flow rate control valve V2 so that the amount of steam q2 flowing through the second steam pipe 44 is equal to the difference between the amount of steam q0 generated in the boiler 21 and the amount of steam q1 supplied to the steam turbine 22 (i.e., so as to satisfy q2 = q0 - q1).

[0044] When the second flow rate control valve V2 is in an open state, the steam generated in the boiler 21 is supplied to the heat exchanger 32 as a heat medium via the second steam pipe 44. The heat exchanger 32 uses the steam generated in the boiler 21 as thermal energy for generating high-temperature steam. This allows the hydrogen production system 3 to generate high-temperature steam without using electricity supplied from the renewable energy power generation facility 4 or by reducing the amount of electricity used from the renewable energy power generation facility 4. When the second flow rate control valve V2 is in a closed state, the hydrogen production system 3 generates high-temperature steam using Joule heat generated by the electricity supplied from the renewable energy power generation facility 4.

[0045] As described above, in the boiler steam turbine system 2, when the outside air temperature becomes too high, such as in summer, the condenser 23 cannot sufficiently cool the exhaust steam, and turbine efficiency decreases. As a result, as shown in FIG. 2(a), the amount of power generated in the steam turbine 22 decreases, and excess steam is generated that cannot be processed by the steam turbine 22 (i.e., is not used for power generation in the steam turbine 22). In conventional steam power plants, the excess steam that cannot be processed by the steam turbine is supplied to the condenser via a turbine bypass. Alternatively, to suppress the generation of excess steam, the amount of steam generated in the boiler is reduced. In conventional steam power plants, the excess steam cannot be utilized, and the system efficiency of the steam power plant decreases. In this embodiment, a second steam pipe 44 is provided to supply steam generated in the boiler 21 as a heat medium to the heat exchanger 32. Therefore, as shown in Fig. 2(b), surplus steam not used for power generation in the steam turbine 22 can be supplied to the heat exchanger 32 via the second steam pipe 44 and effectively utilized as thermal energy for producing hydrogen. This improves the hydrogen production efficiency in the hydrogen production system 3, and can improve the system efficiency of the steam power plant 1.

[0046] The amount of hydrogen produced Ph in the hydrogen production system 3 is expressed by the following equation (2): W is the power required for electrolysis in the hydrogen production device 31, E is the voltage for electrolysis, qh is the amount of heat supplied, and α is a constant. Ph=W / (αE+qh) (2) The amount of heat qj generated by Joule heat using the power supplied from the renewable energy power generation facility 4 is expressed by the following equation (3), where I is the current, R is the resistance, and V is the voltage. qj=I 2 R=VI (3) The heat supply amount qh includes the amount of heat qj supplied by Joule heat using the electricity supplied from the renewable energy power generation facility 4, and the amount of heat qo generated in the heat exchanger 32 using surplus steam supplied to the heat exchanger 32 via the second steam pipe 44. That is, the heat supply amount qh is expressed by the following equation (4). qh=qj+qo=VI+qo (4) From equation (4), it can be seen that when the heat supply qh is constant, by using the excess steam supplied to the heat exchanger 32 via the second steam pipe 44, it is possible to produce hydrogen by reducing the heat quantity qj supplied by Joule heat using electricity supplied from the renewable energy power generation facility 4 by the amount of heat quantity qo.

[0047] The steam power generation plant 1 includes a return pipe 46 that supplies the heat medium after passing through the heat exchanger 32 (i.e., the heat medium used for heat exchange with the raw material in the heat exchanger 32) to the condensate tank 25 or the deaerator 26. The return pipe 46 is provided with a switching valve Vc that switches the supply destination of the heat medium between the condensate tank 25 and the deaerator 26. The return pipe 46 includes a first pipe 47 that connects the heat exchanger 32 and the switching valve Vc, a second pipe 48 that connects the switching valve Vc and the condensate tank 25, and a third pipe 49 that connects the switching valve Vc and the deaerator 26. The first pipe 47 is provided with a seventh pressure sensor 47a that detects a pressure P3 within the first pipe 47 and a fourth temperature sensor 47b that detects a temperature T3 of the heat medium after passing through the heat exchanger 32.

[0048] The switching valve Vc switches the supply destination of the heat medium between the condensate tank 25 and the deaerator 26 based on the temperature T3 of the heat medium after passing through the heat exchanger 32. The temperature T3 of the heat medium after passing through the heat exchanger 32 varies depending on the amount of hydrogen produced by the hydrogen production device 31. For example, when the renewable energy power generation facility 4 supplies an abundant amount of electricity, the amount of hydrogen produced by the hydrogen production device 31 increases, and the amount of heat required to generate high-temperature steam also increases. As a result, the amount of heat transferred from the heat medium to the material in the heat exchanger 32 increases, and the temperature T3 of the heat medium after passing through the heat exchanger 32 decreases, and the heat medium after passing through the heat exchanger 32 is cooled to a drain state of less than 100°C. When the temperature T3 of the heat medium after passing through the heat exchanger 32 is relatively low and the heat medium after passing through the heat exchanger 32 is in a liquid state, the switching valve Vc switches the supply destination of the heat medium to the condensate tank 25. On the other hand, when the amount of hydrogen produced in the hydrogen production device 31 is small, the amount of heat transferred from the heat medium to the raw material in the heat exchanger 32 is small. Therefore, the temperature T3 of the heat medium after passing through the heat exchanger 32 becomes relatively high, and the heat medium after passing through the heat exchanger 32 is in a vapor state that is equal to or higher than saturated vapor. When the temperature T3 of the heat medium after passing through the heat exchanger 32 is relatively high and the heat medium after passing through the heat exchanger 32 is in a gaseous state, the switching valve Vc switches the supply destination of the heat medium to the deaerator 26.

[0049] The configuration of the switching valve Vc will be described with reference to FIG. 3. In this embodiment, the switching valve Vc is a float-type valve. The switching valve Vc includes a valve body 51 having an internal space S, a float 52 disposed in the internal space S, and a lid 53. The valve body 51 is formed with an inlet 51a communicating with the internal space S, a first outlet 51b, and a second outlet 51c. The inlet 51a is connected to the first pipe 47. The first outlet 51b is formed in the lower part of the valve body 51 and is connected to the second pipe 48. The second outlet 51c is formed in the upper part of the valve body 51 and is connected to the third pipe 49. The float 52 opens and closes the first outlet 51b. The lid 53 opens and closes the second outlet 51c.

[0050] 3(a), when the heat medium supplied to the inlet 51a via the first pipe 47 is in a liquid state, the float 52 is lifted by the liquid heat medium (drain water) stored in the internal space S, thereby opening the first outlet 51b. As a result, the liquid heat medium is supplied to the condensate tank 25 through the first outlet 51b and the second pipe 48.

[0051] 3(b), when the heat transfer medium supplied to the inlet 51a via the first pipe 47 is in a gaseous state, the vapor pressure in the internal space S pushes up the lid 53, opening the second outlet 51c. The vapor pressure in the internal space S also pushes the float 52 against the first outlet 51b, blocking the first outlet 51b. As a result, the gaseous heat transfer medium is supplied to the deaerator 26 through the second outlet 51c and the third pipe 49.

[0052] In the hydrogen production system 3, the hydrogen production control unit 34 may track and control the amount of hydrogen produced in the hydrogen production device 31 based on the temperature T3 of the heat medium after passing through the heat exchanger 32. Specifically, when the heat medium after passing through the heat exchanger 32 is returned to the condensate tank 25, the hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31 so as to reduce the difference between the temperature Tc of the feedwater in the condensate tank 25 and the temperature T3 of the heat medium after passing through the heat exchanger 32. Furthermore, when the heat medium after passing through the heat exchanger 32 is returned to the deaerator 26, the hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31 so as to reduce the difference between the temperature Td of the feedwater in the deaerator 26 and the temperature T3 of the heat medium after passing through the heat exchanger 32.

[0053] As described above, the steam power plant 1 according to this embodiment includes a boiler steam turbine system 2 and a hydrogen production system 3. The boiler steam turbine system 2 includes a boiler 21 that generates steam, a steam turbine 22 that is rotated by the steam generated by the boiler 21, a condenser 23 that condenses exhaust steam discharged from the steam turbine 22 to produce drain water, an exhaust condensate tank 24 that stores the drain water condensed by the condenser 23 under negative pressure, a condensate tank 25 that stores the drain water discharged from the exhaust condensate tank 24 under atmospheric pressure, and a deaerator 26 that deaerates feedwater supplied from the condensate tank 25. The hydrogen production system 3 includes a hydrogen production device 31 that produces hydrogen from a raw material, and a heat exchanger 32 that heats the raw material by exchanging heat between the raw material and a heat medium. The steam power plant 1 has a first steam pipe 41 connecting the boiler 21 and the steam turbine 22, a second steam pipe 44 branching from the first steam pipe 41 and supplying steam generated in the boiler 21 as a heat medium to the heat exchanger 32, and a return pipe 46 supplying the heat medium after passing through the heat exchanger 32 to the condensate tank 25 or the deaerator 26. The return pipe 46 is provided with a switching valve Vc that switches the supply destination of the heat medium after passing through the heat exchanger 32 between the condensate tank 25 and the deaerator 26.

[0054] According to this steam power plant 1, the steam generated in the boiler 21 is supplied as a heat medium to the heat exchanger 32 via the second steam pipe 44. Therefore, the steam generated in the boiler 21 can be used as thermal energy for producing hydrogen in the hydrogen production system 3. This improves the system efficiency of the steam power plant 1. Furthermore, the supply destination of the heat medium after passing through the heat exchanger 32 can be switched between the condensate tank 25 and the deaerator 26 depending on the state of the heat medium.

[0055] The switching valve Vc has an internal space S and includes a valve body 51 having an inlet 51a, a first outlet 51b, and a second outlet 51c that communicate with the internal space S, and a float 52 that is disposed in the internal space S and opens and closes the first outlet 51b. The return pipe 46 has a first pipe 47 that connects the heat exchanger 32 and the inlet 51a, a second pipe 48 that connects the first outlet 51b and the condensate tank 25, and a third pipe 49 that connects the second outlet 51c and the deaerator 26. When the heat medium supplied to the inlet 51a via the first pipe 47 is in a liquid state, the float 52 is lifted by the liquid heat medium stored in the internal space S, thereby opening the first outlet 51b. When the heat medium supplied to the inlet 51a via the first pipe 47 is in a gaseous state, the float 52 is pressed against the first outlet 51b by the vapor pressure in the internal space S, thereby blocking the first outlet 51b. The switching valve Vc also has a lid 53 that opens and closes the second outlet 51c. When the heat medium supplied to the inlet 51a through the first pipe 47 is in a gaseous state, the vapor pressure in the internal space S pushes up the lid 53, opening the second outlet 51c. According to the above configuration, the supply destination of the heat medium after passing through the heat exchanger 32 can be easily switched between the condensate tank 25 and the deaerator 26 by the switching valve Vc depending on the state of the heat medium.

[0056] The hydrogen production system 3 further includes a hydrogen production control unit 34 that controls the amount of hydrogen produced by the hydrogen production device 31 based on the temperature T3 of the heat medium after passing through the heat exchanger 32. According to the above configuration, the amount of hydrogen produced in the hydrogen production device 31 can be tracked and controlled based on the temperature T3 of the heat medium after passing through the heat exchanger 32.

[0057] In addition, a first flow control valve V1 is provided on the first steam pipe 41 downstream of the branch point with the second steam pipe 44 to adjust the amount of steam q1 supplied to the steam turbine 22 based on the pressure Pe in the exhaust condensate tank 24. According to the above configuration, the amount of steam q1 supplied to the steam turbine 22 can be tracked and controlled based on the pressure Pe in the exhaust gas condensate tank 24.

[0058] The second steam pipe 44 is provided with a second flow rate control valve V2 that adjusts the amount of steam q2 flowing through the second steam pipe 44. The second flow rate control valve V2 is in an open state when the amount of steam q0 generated in the boiler 21 is greater than the amount of steam q1 supplied to the steam turbine 22. Furthermore, the second flow rate adjustment valve V2 controls the opening degree of the second flow rate adjustment valve V2 so that the amount of steam q2 flowing through the second steam pipe 44 satisfies q2=q0-q1. According to the above configuration, surplus steam that cannot be processed by the steam turbine 22 can be supplied to the heat exchanger 32 via the second steam pipe 44 and effectively utilized as thermal energy for producing hydrogen in the hydrogen production system 3. This can further improve the system efficiency of the steam power plant 1.

[0059] In addition, the hydrogen production device 31 is connected to a renewable energy power generation facility 4, and uses electricity supplied from the renewable energy power generation facility 4 to produce hydrogen using either high-temperature steam electrolysis, alkaline water electrolysis, or solid polymer membrane water electrolysis. According to the above configuration, hydrogen can be produced using renewable energy.

[0060] The hydrogen production device 31 also has an electrochemical cell (electrolysis cell 31a) that produces hydrogen using external electric power. According to the above configuration, hydrogen can be efficiently produced using the steam generated in the boiler 21.

[0061] The hydrogen production system 3 further includes a hydrogen storage tank 33 connected to the hydrogen production device 31 and storing hydrogen produced by the hydrogen production device 31. The electrochemical cell (electrolysis cell 31a) is capable of generating electricity using hydrogen in the hydrogen storage tank 33. According to the above configuration, the hydrogen stored in the hydrogen storage tank 33 can be used for power generation in an emergency or during regular inspection of the steam power plant 1. Furthermore, hydrogen production and power generation using hydrogen can be performed using a single electrochemical cell (electrolysis cell 31a).

[0062] <Modification> The switching valve Vc may be a three-way valve having an inlet 51a, a first outlet 51b, and a second outlet 51c. In this case, the switching valve Vc is controlled by the valve control unit 27 based on the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Tc of the feedwater in the condensate tank 25. Specifically, when T3≦Tc+30 (i.e., when the difference between the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Tc of the feedwater in the condensate tank 25 is small), the valve control unit 27 controls the switching valve Vc to open the first outlet 51b and close the second outlet 51c. As a result, the heat medium after passing through the heat exchanger 32 is supplied to the condensate tank 25 through the first outlet 51b and the second pipe 48. Furthermore, when T3>Tc+30 (when the temperature T3 of the heat medium after passing through the heat exchanger 32 is significantly higher than the temperature Tc of the feedwater in the condensate tank 25), the valve control unit 27 controls the switching valve Vc to close the first outlet 51b and open the second outlet 51c. As a result, the heat medium after passing through the heat exchanger 32 is supplied to the deaerator 26 through the second outlet 51c and the third pipe 49.

[0063] As described above, this modification further includes the valve control unit 27 that controls the switching valve Vc based on the temperature T3 of the heat medium after passing through the heat exchanger 32. The switching valve Vc is a three-way valve having an inlet 51a, a first outlet 51b, and a second outlet 51c. The return pipe 46 has a first pipe 47 connecting the heat exchanger 32 and the inlet 51a, a second pipe 48 connecting the first outlet 51b and the condensate tank 25, and a third pipe 49 connecting the second outlet 51c and the deaerator 26. The valve control unit 27 controls the switching valve Vc to open the first outlet 51b and close the second outlet 51c when T3≦Tc+30, and to close the first outlet 51b and open the second outlet 51c when T3>Tc+30. According to the above configuration, the supply destination of the heat medium after passing through the heat exchanger 32 can be more appropriately switched between the condensate tank 25 and the deaerator 26 based on the temperature T3 of the heat medium after passing through the heat exchanger 32.

[0064] Second Embodiment Next, a steam power plant 1 according to a second embodiment will be described with reference to Fig. 4. The steam power plant 1 according to this embodiment has the same basic configuration as the first embodiment, and therefore differences will be mainly described.

[0065] In this embodiment, the steam power plant 1 has a return pipe 61 instead of the return pipe 46. The return pipe 61 connects the second steam pipe 44 and the condensate tank 25. The return pipe 61 is not provided with a switching valve Vc.

[0066] When the second flow rate control valve V2 is in an open state, the steam generated in the boiler 21 is supplied as a heat medium to the heat exchanger 32 via the second steam pipe 44. The heat exchanger 32 uses the heat of the steam generated in the boiler 21 as thermal energy for producing hydrogen. The return pipe 61 supplies the heat medium after passing through the heat exchanger 32 (i.e., the heat medium used for heat exchange with the raw material in the heat exchanger 32) to the condensate tank 25. The hydrogen production control unit 34 also controls the amount of hydrogen produced in the hydrogen production device 31 so that the difference between the temperature Tc of the feedwater in the condensate tank 25 and the temperature T3 of the heat medium after passing through the heat exchanger 32 is small. When the second flow rate control valve V2 is in a closed state, the hydrogen production system 3 uses Joule heat generated by the electric power supplied from the renewable energy power generation facility 4 to produce hydrogen.

[0067] As described above, the steam power plant 1 according to this embodiment includes a boiler steam turbine system 2 and a hydrogen production system 3. The boiler steam turbine system 2 includes a boiler 21 that generates steam, a steam turbine 22 that is rotated by the steam generated by the boiler 21, a condenser 23 that condenses exhaust steam discharged from the steam turbine 22 to produce drain water, an exhaust condensate tank 24 that stores the drain water condensed by the condenser 23 under negative pressure, a condensate tank 25 that stores the drain water discharged from the exhaust condensate tank 24 under atmospheric pressure, and a deaerator 26 that deaerates feedwater supplied from the condensate tank 25. The hydrogen production system 3 includes a hydrogen production device 31 that produces hydrogen from a raw material, a heat exchanger 32 that heats the raw material by exchanging heat between the raw material and a heat medium, and a hydrogen production control unit 34 that controls the hydrogen production device 31. The steam power plant 1 has a first steam pipe 41 connecting the boiler 21 and the steam turbine 22, a second steam pipe 44 branching from the first steam pipe 41 and supplying steam generated in the boiler 21 as a heat medium to the heat exchanger 32, and a return pipe 61 supplying the heat medium after passing through the heat exchanger 32 to the condensate tank 25. The hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31 so that the difference between the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Tc of the feedwater in the condensate tank 25 is small.

[0068] In this steam power plant 1, steam generated in the boiler 21 is supplied as a heat medium to the heat exchanger 32 via the second steam pipe 44. Therefore, the steam generated in the boiler 21 can be used as thermal energy for producing hydrogen in the hydrogen production system 3. This improves the system efficiency of the steam power plant 1. Furthermore, the heat medium after passing through the heat exchanger 32 is supplied to the condensate tank 25. At this time, the hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31, making it possible to reduce the difference between the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Tc of the feedwater in the condensate tank 25.

[0069] Third Embodiment Next, a steam power plant 1 according to a third embodiment will be described with reference to Fig. 5. The steam power plant 1 according to this embodiment has the same basic configuration as the first embodiment, and therefore differences will be mainly described.

[0070] In this embodiment, the steam power plant 1 has a return pipe 62 instead of the return pipe 46. The return pipe 62 connects the second steam pipe 44 and the deaerator 26. The return pipe 62 is not provided with a switching valve Vc.

[0071] When the second flow rate control valve V2 is in an open state, the steam generated in the boiler 21 is supplied as a heat medium to the heat exchanger 32 via the second steam pipe 44. The heat exchanger 32 uses the heat of the steam generated in the boiler 21 as thermal energy for producing hydrogen. The return pipe 62 supplies the heat medium after passing through the heat exchanger 32 (i.e., the heat medium used for heat exchange with the raw material in the heat exchanger 32) to the deaerator 26. The hydrogen production control unit 34 also controls the amount of hydrogen produced in the hydrogen production device 31 so that the difference between the temperature Td of the feedwater in the deaerator 26 and the temperature T3 of the heat medium after passing through the heat exchanger 32 is small. When the second flow rate control valve V2 is in a closed state, the hydrogen production system 3 uses Joule heat generated by the electric power supplied from the renewable energy power generation facility 4 to produce hydrogen.

[0072] As described above, the steam power plant 1 according to this embodiment includes a boiler steam turbine system 2 and a hydrogen production system 3. The boiler steam turbine system 2 includes a boiler 21 that generates steam, a steam turbine 22 that is rotated by the steam generated by the boiler 21, a condenser 23 that condenses exhaust steam discharged from the steam turbine 22 to produce drain water, an exhaust condensate tank 24 that stores the drain water condensed by the condenser 23 under negative pressure, a condensate tank 25 that stores the drain water discharged from the exhaust condensate tank 24 under atmospheric pressure, and a deaerator 26 that deaerates feedwater supplied from the condensate tank 25. The hydrogen production system 3 includes a hydrogen production device 31 that produces hydrogen from a raw material, a heat exchanger 32 that heats the raw material by exchanging heat between the raw material and a heat medium, and a hydrogen production control unit 34 that controls the hydrogen production device 31. The steam power plant 1 has a first steam pipe 41 connecting the boiler 21 and the steam turbine 22, a second steam pipe 44 branching from the first steam pipe 41 and supplying steam generated in the boiler 21 as a heat medium to the heat exchanger 32, and a return pipe 62 supplying the heat medium after passing through the heat exchanger 32 to the deaerator 26. The hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31 so that the difference between the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Td of the feedwater in the deaerator 26 is small.

[0073] In this steam power plant 1, steam generated in the boiler 21 is supplied as a heat medium to the heat exchanger 32 via the second steam pipe 44. Therefore, the steam generated in the boiler 21 can be used as thermal energy for producing hydrogen in the hydrogen production system 3. This improves the system efficiency of the steam power plant 1. Furthermore, the heat medium after passing through the heat exchanger 32 is supplied to the deaerator 26. At this time, the hydrogen production control unit 34 controls the amount of hydrogen produced in the hydrogen production device 31, thereby making it possible to reduce the difference between the temperature T3 of the heat medium after passing through the heat exchanger 32 and the temperature Td of the feedwater in the deaerator 26.

[0074] While preferred embodiments of the present invention have been described and illustrated, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the present invention should not be deemed limited by the foregoing description, but rather by the scope of the claims. [Explanation of symbols]

[0075] 1. Steam power plant 2. Boiler steam turbine system 21 Boiler 22 Steam turbine 23 Condenser 24 Exhaust condensate tank 25 Condensate tank 26 Deaerator 27 Valve control section 3 Hydrogen production system 31 Hydrogen production equipment 31a Electrolytic cell (electrochemical cell) 32 Heat exchanger 33 Hydrogen storage tank 34 Hydrogen production control unit 41 No. 1 Steam Pipe 44 Second Steam Pipe 46, 61, 62 Return pipes 47 First Pipe 48 Second Pipe 49 Third Pipe V1 First flow control valve V2 Second flow control valve Vc switching valve 51 Valve body 51a Inlet 51b 1st outlet 51c 2nd outlet 52 Float 53 Lid

Claims

1. 1. A steam power plant comprising a boiler steam turbine system and a hydrogen production system, The boiler steam turbine system includes: A boiler that generates steam; a steam turbine that is rotated by steam generated in the boiler; a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water; an exhaust condensate tank that stores the drain water condensed by the condenser under negative pressure; a condensate tank that stores the drain water discharged from the exhaust condensate tank at atmospheric pressure; a deaerator that deaerates the feedwater supplied from the condensate tank; and The hydrogen production system includes: a hydrogen production device for producing hydrogen from a raw material; a heat exchanger that heats the raw material by exchanging heat between the raw material and a heat medium; and The steam power plant comprises: a first steam pipe connecting the boiler and the steam turbine; a second steam pipe branching from the first steam pipe and supplying steam generated in the boiler to the heat exchanger as the heat medium; a return pipe that supplies the heat medium after passing through the heat exchanger to the condensate tank or the deaerator, The return pipe is provided with a switching valve that switches the supply destination of the heat medium after passing through the heat exchanger between the condensate tank and the deaerator. Steam power plant.

2. The switching valve is a valve body having an internal space and having an inlet, a first outlet, and a second outlet formed therein, the inlet and the second outlet communicating with the internal space; a float disposed in the internal space and closing the first outlet in an openable and closable manner; the return pipe includes a first pipe connecting the heat exchanger and the inlet, a second pipe connecting the first outlet and the condensate tank, and a third pipe connecting the second outlet and the deaerator, When the heat medium supplied to the inlet through the first pipe is in a liquid state, the float is lifted up by the liquid heat medium stored in the internal space, thereby opening the first outflow port; When the heat medium supplied to the inlet through the first pipe is in a gaseous state, the float is pressed against the first outlet by vapor pressure in the internal space, thereby blocking the first outlet. The steam power plant of claim 1 .

3. the switching valve has a cover that closes the second outlet in an openable and closable manner, When the heat medium supplied to the inlet through the first pipe is in a gaseous state, the lid is pushed up by vapor pressure in the internal space, thereby opening the second outlet. The steam power plant of claim 2.

4. The heat exchanger further includes a valve control unit that controls the switching valve based on the temperature of the heat medium after passing through the heat exchanger. The steam power plant of claim 1 .

5. the switching valve is a three-way valve having an inlet, a first outlet, and a second outlet; the return pipe includes a first pipe connecting the heat exchanger and the inlet, a second pipe connecting the first outlet and the condensate tank, and a third pipe connecting the second outlet and the deaerator, When a temperature of the heat medium after passing through the heat exchanger is T3 and a temperature of the feedwater in the condensate tank is Tc, the valve control unit controls the switching valve to open the first outlet and close the second outlet when T3≦Tc+30, and controls the switching valve to close the first outlet and open the second outlet when T3>Tc+30. The steam power plant of claim 4.

6. the hydrogen production system further includes a hydrogen production control unit that controls the amount of hydrogen produced in the hydrogen production device based on the temperature of the heat medium after passing through the heat exchanger. The steam power plant of claim 1 .

7. a first flow control valve that adjusts the amount of steam supplied to the steam turbine based on the pressure in the exhaust condensate tank, provided in the first steam pipe downstream of a branch point with respect to the second steam pipe; The steam power plant of claim 1 .

8. a second flow rate adjustment valve that adjusts the amount of steam flowing through the second steam pipe; The second flow control valve is opened when the amount of steam generated in the boiler is greater than the amount of steam supplied to the steam turbine. The steam power plant of claim 7.

9. When the amount of steam generated in the boiler is q0 and the amount of steam supplied to the steam turbine is q1, the second flow rate control valve controls the opening degree of the second flow rate control valve so that the amount of steam flowing through the second steam pipe q2 satisfies q2 = q0 - q1. The steam power plant of claim 8.

10. 1. A steam power plant comprising a boiler steam turbine system and a hydrogen production system, The boiler steam turbine system includes: A boiler that generates steam; a steam turbine that is rotated by steam generated in the boiler; a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water; an exhaust condensate tank that stores the drain water condensed by the condenser under negative pressure; a condensate tank that stores the drain water discharged from the exhaust condensate tank at atmospheric pressure; a deaerator that deaerates the feedwater supplied from the condensate tank; and The hydrogen production system includes: a hydrogen production device for producing hydrogen from a raw material; a heat exchanger that heats the raw material by exchanging heat between the raw material and a heat medium; a hydrogen production control unit that controls the hydrogen production device; and The steam power plant comprises: a first steam pipe connecting the boiler and the steam turbine; a second steam pipe branching from the first steam pipe and supplying steam generated in the boiler to the heat exchanger as the heat medium; a return pipe that supplies the heat medium after passing through the heat exchanger to the condensate tank, the hydrogen production control unit controls the amount of hydrogen produced in the hydrogen production device so that a difference between the temperature of the heat medium after passing through the heat exchanger and the temperature of the feedwater in the condensate tank becomes small. Steam power plant.

11. 1. A steam power plant comprising a boiler steam turbine system and a hydrogen production system, The boiler steam turbine system includes: A boiler that generates steam; a steam turbine that is rotated by steam generated in the boiler; a condenser that condenses exhaust steam discharged from the steam turbine to produce drain water; an exhaust condensate tank that stores the drain water condensed by the condenser under negative pressure; a condensate tank that stores the drain water discharged from the exhaust condensate tank at atmospheric pressure; a deaerator that deaerates the feedwater supplied from the condensate tank; and The hydrogen production system includes: a hydrogen production device for producing hydrogen from a raw material; a heat exchanger that heats the raw material by exchanging heat between the raw material and a heat medium; a hydrogen production control unit that controls the hydrogen production device; and The steam power plant comprises: a first steam pipe connecting the boiler and the steam turbine; a second steam pipe branching from the first steam pipe and supplying steam generated in the boiler to the heat exchanger as the heat medium; a return pipe that supplies the heat medium after passing through the heat exchanger to the deaerator, the hydrogen production control unit controls the amount of hydrogen produced in the hydrogen production device so that a difference between the temperature of the heat medium after passing through the heat exchanger and the temperature of the feedwater in the deaerator is small. Steam power plant.

12. a first flow control valve that adjusts the amount of steam supplied to the steam turbine based on the pressure in the exhaust condensate tank, provided in the first steam pipe downstream of a branch point with respect to the second steam pipe; The steam power plant according to claim 10 or 11.

13. the hydrogen production device is connected to a renewable energy power generation facility and produces hydrogen by any one of high-temperature steam electrolysis, alkaline water electrolysis, and solid polymer membrane water electrolysis using electric power supplied from the renewable energy power generation facility; 12. The steam power plant of claim 1, 10 or 11.

14. The hydrogen production device has an electrochemical cell that produces hydrogen using external power.

12. The steam power plant of claim 1, 10 or 11.

15. the hydrogen production system further includes a hydrogen storage tank connected to the hydrogen production device and storing hydrogen produced by the hydrogen production device; The electrochemical cell is capable of generating electricity using hydrogen in the hydrogen storage tank.

15. The steam power plant of claim 14.

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