SYSTEM HAVING A COMBUSTION POWER PLANT AND AN ELECTROLYSIS UNIT, AND METHOD FOR OPERATING A SYSTEM OF THIS TYPE

Abstract

A system includes a combustion power plant for generating power and an electrolysis unit for producing hydrogen. The combustion power plant has a combustion chamber for combustion of a fuel and an offgas conduit for leading off hot offgases formed in the combustion of the fuel. The offgas conduit is thermally coupled to the electrolysis unit. A method for operating the system includes burning the fuel in the combustion power plant, forming the hot offgases in the combustion of the fuel, removing the hot offgases through the offgas conduit, feeding the thermal energy of the hot offgases from the offgas conduit to the electrolysis unit, and producing hydrogen in the electrolysis unit by using the thermal energy from the hot offgases.

Claims

1-15 (canceled)

16. A system, comprising: a combustion power plant for generating power and an electrolysis unit for producing hydrogen; said combustion power plant having a combustion chamber for combustion of a fuel and an offgas conduit for leading off hot offgases formed in the combustion of the fuel; and said offgas conduit being thermally coupled to said electrolysis unit.

17. The system according to claim 16, which further comprises a heat pipe thermally coupling said offgas conduit to said electrolysis unit.

18. The system according to claim 16, which further comprises a renewable power generation source electrically coupled to said electrolysis unit.

19. The system according to claim 16, which further comprises an open-loop control device configured to control a rate of heat transfer from said offgas conduit to said electrolysis unit.

20. The system according to claim 19, which further comprises a closed-loop control device configured to compensate for any fluctuation in an operating temperature of said electrolysis unit resulting from a fluctuation in a power supplied to said electrolysis unit by control exerted by said open-loop control device.

21. The system according to claim 20, wherein said closed-loop control device is configured to control said open-loop control device to ensure that a constant or substantially constant amount of hydrogen is produced by said electrolysis unit.

22. The system according to claim 16, which further comprises: a steam generator thermally coupled to said offgas conduit to generate steam from waste heat from the offgas; and a first fluid conduit coupling said steam generator to said electrolysis unit; said first fluid conduit configured to feed steam generated from waste heat in said steam generator to said electrolysis unit.

23. The system according to claim 22, which further comprises: a fourth fluid conduit coupled to said electrolysis unit and configured to remove the hydrogen produced in said electrolysis unit; and a heat exchanger coupling said first fluid conduit to said fourth fluid conduit.

24. The system according to claim 23, wherein: said combustion power plant includes a steam turbine; a second fluid conduit couples said steam generator to said steam turbine, said second fluid conduit is configured to expand the steam generated in said steam generator from the waste heat from the offgas; a first load is coupled to said steam turbine; and a third fluid conduit couples said steam turbine to said steam generator for recycling steam expanded in said steam turbine.

25. The system according to claim 24, which further comprises: a fifth fluid conduit coupled to said electrolysis unit and to said combustion power plant; said fifth fluid conduit configured to feed oxygen produced in said electrolysis unit to said combustion power plant for the combustion of the fuel.

26. The system according to claim 16, wherein said combustion power plant is a gas turbine or a refuse power plant.

27. A method of operating a system, the method comprising: providing the system according to claim 16: burning the fuel in said combustion power plant; forming the hot offgases in the combustion of the fuel; removing the hot offgases by using the offgas conduit; feeding thermal energy of the hot offgases from said offgas conduit to said electrolysis unit; and producing hydrogen in said electrolysis unit by using the thermal energy from the hot offgases.

28. The method according to claim 27, which further comprises: providing the system with an open-loop control device configured to control a rate of heat transfer from said offgas conduit to said electrolysis unit; supplying power to said electrolysis unit; and compensating for any fluctuation in an operating temperature of said electrolysis unit resulting from any fluctuation in the power supplied to said electrolysis unit by control exerted by said open-loop control device.

29. The method according to claim 28, which further comprises controlling said open-loop control device to produce a constant or substantially constant amount of hydrogen.

Description

[0034] The electrolysis unit 30 takes the form of a high-temperature electrolyzer. The electrolysis unit 30 has multiple electrolysis cells and at least one membrane 31, indicated in FIG. 1. The membrane 31 is permeable to oxygen ions. By application of a sufficiently high voltage by means of the power line G, in the present case power branch G.5, across the at least one membrane 31, steam H2O supplied by means of a first fluid conduit D, which can also be referred to as water or steam conduit D, is split into oxygen O2 and hydrogen H2.

[0035] The oxygen O2 produced is removed in a fifth fluid conduit B, which can also be referred to as oxygen conduit and which is identified as B.2 in the present context. This oxygen O2 produced can advantageously be fed to the compressor 12 by means of the fifth fluid conduit B, identified as B.1 in the present context, in order to increase the efficiency of the system 100.

[0036] The hydrogen H2 is removed in a fourth fluid conduit C, which can also be referred to as hydrogen conduit, by means of a heat exchanger 23, a second condenser 32 and a second pump 33. The fourth fluid conduit C in the present context leads to a storage means 34 for hydrogen H2. By means of the heat exchanger 23, heat is exchanged between hot hydrogen H2 produced from the electrolysis unit 30 and the steam H2O in the first fluid conduit D. For this purpose, the first fluid conduit D leads from a steam generator 20 to the heat exchanger 23, in the present context with a first section D.1 of the first fluid conduit D, and from the heat exchanger 23 to the electrolysis unit 30, in the present context with a second section D.2 of the first fluid conduit D.

[0037] The power supplied to the electrolysis unit 30 may come from various sources. It may especially be the case that the electrolysis unit 30 draws power from a renewable power generation source 50. In the present context, this is shown by the connection of the power line G by means of the power line branches G.4, G.5 of renewable power generation source 50 and electrolysis unit 30. It is also possible for the combustion power plant 10 to have the second load 15, which may take the form of an electrical generator. For instance, the power generated by the second load 15 of the combustion power plant 10 can be supplied to the electrolysis unit 30 by means of the power line branches G.1, G.3, G.5. It is also possible for the steam turbine 16 to be coupled to a first load 17 in the form of an electrical generator. This too can supply power in this way to the electrolysis unit 30 by means of the power line branches G.2, G.3, G.5.

[0038] The steam generator 20 is thermally coupled to an offgas conduit A coupled to the turbine 13 of the combustion power plant 10, in the present context by means of a first offgas conduit branch A.1. Hot offgases from the combustion power plant 10 are transported in the offgas conduit A. The heat from these hot offgases is utilized in the steam generator 20. The steam generator 20 is set up to heat water to give steam and/or to heat steam. For this purpose, it can use power and/or the thermal energy from the offgases.

[0039] The steam generator 20 is coupled to the steam turbine 16 by means of a second fluid conduit E. The second fluid conduit E has a second fluid conduit section E.1 from the steam generator 20 to a first valve 18, and a second fluid conduit section E.2 from the first valve to the steam turbine 16. The first valve may correspondingly be opened in order to guide the heated steam to the steam turbine 16. In this way, it is possible to utilize the thermal energy from the offgases from the combustion power plant 10 for generation of power by means of the first load 17 in the form of an electrical generator. By means of a third fluid conduit H with the third fluid conduit sections H.1, H.2 and first condenser 19 disposed therein and first pump 21, the condensed water can be fed back to the steam generator 20, resulting in a closed circuit.

[0040] In addition, the steam generator 20 is coupled to the electrolysis unit 30 by means of the first fluid conduit D. A second valve 22 is disposed in the first fluid conduit D, to be exact in the first fluid conduit section D.1. When the second valve 22 is opened with the first valve 18 closed, the steam generated and heated with the aid of the thermal energy from the offgases can be provided at the electrolysis unit 30.

[0041] The offgas conduit A has a second offgas conduit branch A.2. The offgas conduit A is thermally coupled to the electrolysis unit 30 by means of the second offgas conduit branch A.2, in order to supply heat to the electrolysis unit 30 and hence to lower the power requirement of the electrolysis unit 30 for splitting of water. In the present context, the offgas conduit A is thermally coupled to the electrolysis unit 30 by means of a heat pipe 40. The heat pipe 40 in the present context takes the form of a heat pipe. In addition, the heat pipe 40 in the present context has an open-loop control device 41. The open-loop control device 41 enables open-loop control of the rate of heat transfer of the heat or thermal energy from the offgas in offgas conduit A from offgas conduit A to the electrolysis unit 30. In the present context, the open-loop control device 41 takes the form of an adjustment device 41. By adjusting the heat pipe 40, it is possible to thermally couple the offgas conduit A to the electrolysis unit 30, and to decouple them. As a result, the adjustment of the heat pipe 40 makes it possible to determine whether heat from the offgas is or is not supplied to the electrolysis unit 30 by means of the heat pipe 40.

[0042] The open-loop control device 41 is connected to a closed-loop control unit 42 for control purposes by means of a closed-loop control conduit F, in the present context closed-loop control conduit section F.1. The closed-loop control device 42 controls the open-loop control exerted by the open-loop control device 41. In addition, the closed-loop control device 42 is connected to the renewable power generation source 50 for control purposes by means of the closed-loop control conduit F, in the present context closed-loop control conduit section F.2. This makes it possible for the closed-loop control device 42 to react to fluctuations in the power supply to the electrolysis unit 30 by corresponding control exerted by the open-loop control device 41. This can avoid fluctuations in the operating temperature of the electrolysis unit 30, in order to increase the lifetime of the electrolysis unit 30. In addition, by appropriate closed-loop control of the rate of heat transfer, it is also possible for a constant or essentially constant amount of hydrogen to be produced by the electrolysis unit 30, even if the power supply is fluctuating.