PRODUCTION OF ELECTRICAL ENERGY FROM HYDROGEN AND OXYGEN

Description

[0001] The invention relates to a device and a method for generating electrical energy from hydrogen and oxygen.

[0002] Conventional power plants burn fossil fuels such as coal or hydrocarbons, releasing carbon dioxide (CO2) into the atmosphere. Internationally, it is now a political goal to replace conventional power plants with clean power plants, ideally with no CO2 as a combustion product and also free of other emissions such as nitrogen oxides.

[0003] Hydrogen (H2) is the focus of development because the combustion of hydrogen does not produce carbon dioxide (CO2) as a reaction product. However, whether hydrogen can be considered a largely CO2-neutral fuel depends on the method of production. Hydrogen produced via water electrolysis using electricity generated from renewable energy sources produces no CO2 emissions and is commonly referred to as green hydrogen. The production of CO2-neutral hydrogen is always complex and expensive.

[0004] Hydrogen is also needed in alternative scenarios, such as ammonia synthesis and subsequent fertilizer production. The demand for CO2-neutral hydrogen is high and will continue to grow in the future. However, supply is scarce and will continue to be a scarce commodity. A power plant that uses hydrogen to generate electrical energy will need to be highly efficient to operate economically.

[0005] It is expected that in the future, electrical energy will be generated largely from renewable sources such as solar and wind. Conventional power plants will have to be used primarily when renewable energy sources are not available in sufficient quantities. For a conventional power plant, this means that the number of possible operating hours will be severely limited. Consequently, such a power plant will be in demand at low specific investment costs.

[0006] Internal combustion engines, such as gas turbines or gas engines, are already known, in which hydrogen or a mixture of hydrogen and natural gas is burned with air to generate electricity. These internal combustion engines also enable power plant concepts that utilize the exhaust heat of the internal combustion engine via conventional steam cycles. However, the efficiencies are currently lower compared to pure natural gas-fired gas and steam power plants. Document US2019 / 390577A1 discloses a device comprising an internal combustion engine according to the prior art.

[0007] Fuel cells, in which electrical energy is generated using hydrogen, are also known. However, fuel cells currently have very high specific investment costs compared to internal combustion engines. This is not expected to change in the future. The comparatively higher efficiency compared to internal combustion engines is unlikely to be relevant in grid-connected power plants, as the operating hours are too few to be economically viable.

[0008] The object of the invention is to provide a device and a method for a green energy generation concept which combines a very high efficiency with the lowest specific investment costs, is largely emission-free and can be used flexibly.

[0009] The object of the invention directed to a device is achieved by the features of claim 1.

[0010] The device according to the invention for generating electrical energy from hydrogen and oxygen comprises an internal combustion engine, in particular a gas turbine and a waste heat steam generator connected in the exhaust duct of the internal combustion engine, which has only one pressure stage, a steam turbine, a generator connected to the steam turbine and a line.According to the invention, an H2-O2 reactor is further provided, to which steam from the heat recovery steam generator, water, oxygen and hydrogen can be fed, so that in the H2-O2 reactor a reaction of oxygen and hydrogen to form steam can be achieved, in which reaction the water introduced evaporates, whereby additional steam can be generated, whereby the resulting highly superheated steam can be fed to the steam turbine, and electrical power can be provided by the generator connected to the steam turbine, and for the targeted control of the reaction in the H2-O2 reactor and for setting the steam outlet temperature from the H2-O2 reactor, high-pressure feed water (14) from the heat recovery steam generator can be injected into the H2-O2 reactor via the line.

[0011] The invention is based on the idea of ​​using a conventional gas turbine or gas engine and a conventional heat recovery steam generator. The internal combustion engine can be fired entirely with hydrogen or partially with hydrogen and natural gas. The heat recovery steam generator has only one pressure stage and thus only one pressure level. It is designed to produce only moderately superheated steam or even saturated steam.

[0012] According to the invention, an H2-O2 reactor is also provided, which reacts hydrogen and oxygen in a steam atmosphere provided by the heat recovery steam generator. This reaction results in the combustion product, steam. Thus, the combustion product and the circulation medium in the steam cycle of the heat recovery steam generator are of the same type.

[0013] The invention uniquely recognizes that a conventional gas turbine and a conventional heat recovery steam generator, which delivers slightly superheated steam at a certain pressure level, can be combined with an H2-O2 reactor to generate highly superheated steam while simultaneously ideally utilizing the exhaust heat. The steam produced during the reaction of hydrogen and oxygen, which is under high pressure and temperature, is introduced into the steam cycle and can be utilized as a circulation medium up to the level defined in the condenser.

[0014] If natural gas is only partially replaced by hydrogen as a fuel, the invention makes it possible to use hydrogen where it is most beneficial. By using hydrogen in the steam cycle, the efficiency relative to this fuel mass flow can be significantly increased compared to its use in a gas turbine.

[0015] When operating the H2-O2 reactor, care must be taken to ensure the most complete conversion possible, especially of hydrogen and, to a somewhat lesser extent, of oxygen. Hydrogen can adversely affect the properties of the material used in the steam turbine through hydrogen embrittlement and can lead to corrosion. To ensure the most complete conversion of hydrogen, the device is preferably controlled so that a certain excess of oxygen is present. Any excess oxygen can preferably be removed via the vacuum system at the condenser of the steam cycle. Alternatively, excess oxygen can also be removed by other measures, such as membrane degassers, in order to largely avoid oxygen in other areas of the steam cycle.In particular, if a preheating line for cold feed water is installed upstream of the heat recovery steam generator, there is also a need to remove non-condensable gases from the circuit in this area.

[0016] For targeted control of the reaction in the H2-O2 reactor, feedwater from the heat recovery steam generator can be injected via the line into the H2-O2 reactor. By injecting feedwater, the reaction in the H2-O2 reactor can be specifically influenced. This can, for example, prevent flashbacks and specifically adjust the steam temperature at the reactor outlet. The feedwater is injected into the H2-O2 reactor at a suitable point (e.g. in the reaction zones of hydrogen and oxygen or in a mixing section at the reactor outlet). The feedwater is high-pressure feedwater from the heat recovery steam generator, preferably from the outlet of the economizer.

[0017] To increase output, it can also be advantageous to add cold feedwater, which is taken upstream of the heat recovery steam generator. Cold feedwater is particularly advantageous because, depending on the power plant design, e.g., the required live steam parameters, the waste heat from the gas turbine exhaust gas has already been optimally utilized and no additional heat is available, yet a correspondingly increased steam turbine output is desired. While adding cold feedwater has a negative impact on efficiency, this is accepted to reduce specific investment costs.

[0018] The heat recovery steam generator can be designed, for example, as a natural circulation or once-through type. The latter offers increased plant flexibility (e.g., shorter start-up times), especially at very high evaporation pressures. To increase plant efficiency, one or more taps on the steam turbine can be used. These taps heat condensate and / or feedwater with low-grade steam via appropriate heat exchangers, thus enabling more high-grade steam to be generated in the heat recovery steam generator and / or the H2O2 reactor.

[0019] In a particular further development of the invention, a desuperheater, designed as a heat exchanger, is integrated upstream of the condenser. The desuperheater is connected on the primary side in the steam line between the steam turbine and a condenser downstream of the steam turbine to absorb heat. For heat dissipation, the desuperheater is connected on the secondary side in the line for supplying additional feedwater, not preheated in the heat recovery steam generator, to the H2-O2 reactor. The desuperheater is required when very high live steam parameters of, for example, 1300°C and 150 bar pressure are generated with the H2-O2 reactor. At the outlet of the steam turbine, there is still highly superheated steam, which is desuperheated by the desuperheater before it is condensed in the condenser.If very high live steam pressures and temperatures are selected, it may be advantageous to design the waste heat steam generator as a once-through boiler instead of a natural circulation (drum) boiler.

[0020] Preferably, the evaporation pressure in the heat recovery steam generator is set high enough to prevent moisture from forming at the steam turbine outlet, depending on the fresh steam temperature set via the H2-O2 reaction. The superheat in the heat recovery steam generator is set high enough to ensure optimal utilization of the exhaust gas heat without the need for additional evaporator pressure stages. Since the focus is on optimal utilization of the exhaust gas heat and, at the same time, the aim is to implement a concept that is as simple and cost-effective as possible, the evaporation pressure is set high enough, depending on the fresh steam temperature set via the H2-O2 reaction, to ensure that no moisture problems leading to blade erosion occur at the respective condenser pressure at the steam turbine outlet, even without intermediate superheating.

[0021] A further advantageous embodiment of the invention further comprises an electrically operated superheater, which is connected upstream of the H2-O2 reactor and by means of which, when the H2-O2 reactor is not in operation, the live steam temperature of the steam can be increased to such an extent that moisture is avoided at the steam turbine outlet. In view of the currently inadequate hydrogen infrastructure and the possible resulting hydrogen supply bottlenecks, it may be advantageous to provide such an option in the cycle, which ensures continued operation of the H2-O2 reactor even without a hydrogen / oxygen supply.

[0022] In an advantageous further development of the invention, the heat recovery steam generator has heating surfaces that form a first evaporator and a second evaporator, and heating surfaces that form a first superheater, with the first superheater being arranged between the heating surfaces of the first evaporator and the second evaporator, thus avoiding any potential delay during gas turbine start-up. This offers the advantage that the gas turbine can always be started up with full gradient, even if the heat recovery steam generator is depressurized and the superheater is still dry and therefore uncooled.

[0023] In principle, it is also advantageous to feed the steam generated by the H2-O2 reactor into a district heating network. For this purpose, the steam turbine must be equipped with appropriate bleeds or, if necessary, designed as a backpressure turbine.

[0024] The object of the invention directed to a method is achieved by the features of claim 9. The advantages of the device according to the invention also apply to the method.

[0025] The method according to the invention for generating electrical energy from hydrogen and oxygen comprises an internal combustion engine, in particular a gas turbine, and a waste heat steam generator connected in the exhaust duct of the internal combustion engine, which has only one pressure stage, a steam turbine (11), a generator (12) connected to the steam turbine (11) and a line (19).Furthermore, an H 2 -O 2 reactor is provided, to which steam from the heat recovery steam generator, water, oxygen and hydrogen are fed, so that in the H 2 -O 2 reactor oxygen and hydrogen react to form water vapor, and further water vapor is produced by evaporation of the injected water, wherein the water vapor is fed to the steam turbine and electrical power is generated by the generator connected to the steam turbine, and the reaction in the H 2 -O 2 reactor is preferably controlled in a targeted manner by injecting feed water from the heat recovery steam generator into the H 2 -O 2 reactor via the line.

[0026] Preferably, high-pressure feed water from the outlet of the economizer of the heat recovery steam generator is used.

[0027] At very high steam parameters downstream of the H 2 -O 2 reactor (e.g. 150 bar and 1300 °C), a desuperheater is preferably integrated upstream of the condenser in the steam cycle. This desuperheater is designed as a heat exchanger, which is connected on the primary side into the steam line between the steam turbine and a condenser downstream of the steam turbine in order to absorb heat, and on the secondary side is connected into a line in order to release heat.

[0028] It is also advantageous to have one or more condensate / feedwater preheaters, whereby steam is taken from one or more taps on the steam turbine and fed to the preheaters for heating purposes in order to increase efficiency.

[0029] The evaporation pressure in the heat recovery steam generator is preferably set only so high that, depending on the fresh steam temperature set via the H 2 -O 2 reaction, moisture is avoided at the outlet of the steam turbine, even without intermediate superheating.

[0030] In a special further development, an electrically operated superheater is provided, which is connected upstream of the H 2 -O 2 reactor and by means of which the fresh steam temperature of the steam can be increased if necessary (H 2 -O 2 reactor not in operation or only with reduced power in operation) to such an extent that moisture is avoided at the outlet of the steam turbine.

[0031] In a particular embodiment of the invention, the waste heat steam generator comprises heating surfaces forming a first evaporator and a second evaporator, and heating surfaces forming a first superheater, wherein the first superheater is arranged between the heating surfaces of the first evaporator and the second evaporator, so that a delay potential during the start-up of the gas turbine is avoided.

[0032] The invention has a number of advantages over a conventional combined cycle power plant (CCPP), which uses hydrogen entirely or partially as fuel for the gas turbine: The efficiency in general, and especially in the case of only partial replacement of natural gas with hydrogen, is higher than in a CCPP based on the same gas turbine. This is due to the fact that Live steam pressure and temperature can be selected to be higher than would be possible with the exhaust gas temperature level of the gas turbine, the heat contained in the exhaust gas of the gas turbine is better utilized, i.e. the exhaust gas temperature at the outlet of the stack is lower, the water vapor under high pressure and temperature that is produced during the reaction of hydrogen and oxygen can be seen as a circulating medium and can therefore be utilized down to the level defined in the condenser, with increased hydrogen content in the gas turbine fuel gas compared to natural gas the combustion temperature still has to be reduced significantly in order to keep flashback, nitrogen oxide emissions, etc. under control. The temperature in the reactor, on the other hand, is much lower and can also be controlled very precisely by injecting feedwater, so the potential of hydrogen combustion can be better utilized.If natural gas is only partially replaced as a fuel, hydrogen is used where it is most useful. By using hydrogen in the steam cycle, the efficiency based on this fuel mass flow is over 50%, which is significantly higher than the efficiency of gas turbines.

[0033] The output actually increases significantly in comparison and can be increased even further by partially sacrificing the efficiency advantage over combined cycle power. To improve specific costs, the output of the steam turbine can be more than doubled, with live steam parameters that are easily achievable today and an efficiency still similar to that of a combined cycle power plant, thus exceeding the output share of the gas turbine.

[0034] The comparatively improved performance and efficiency are achieved at approximately the same cost, as savings and increases are roughly balanced. This can be illustrated in terms of savings as follows: There is only one (instead of several pressure stages as is usually the case with combined cycle power plants) heat recovery steam generator made of inexpensive steel and no expensive high-temperature heating surfaces for superheaters or reheaters. This also eliminates the need for final and intermediate injections. There is only one (instead of several as in combined cycle power plants and often also cold and hot reheaters) and comparatively cold main steam line (thus made of inexpensive steel) from the boiler to the H2-O2 reactor, which is preferably located as close to the steam turbine as possible in order to keep the high-temperature main steam line required downstream of it as short as possible. No demineralized water treatment plant is required for the additional supply of circulating water. In principle, this power plant with the appropriate recooling system is not just a water-free power plant, it is even a water-producing one.This applies if the electrolyzer, which produces hydrogen and oxygen and requires water as a raw material, is not operated on-site or if blue hydrogen is used in combination with oxygen obtained from air.

[0035] In addition to the H 2 -O 2 reactor as an additional element, the invention requires, if necessary, adjustments to the turbo set of the steam turbine and to the circulation pumps (increased high-pressure steam mass flow), an oxygen supply system and an enlargement of the recooling system.

[0036] The enlargement of the cooling system can be fully or partially compensated for in air condensers and once-through cooling systems with limited warm-up time by the extensive use of eco-bypass circuits in the boiler, which is possible via the indentation process, since a large amount of heat can be dissipated via the exhaust gas during the steam bypass operation, which otherwise determines the design.

[0037] A further advantage is the significantly improved flexibility compared to a combined cycle power plant. This is reflected in, among other things, the following: Since the first heating surface exposed to the hot exhaust gas stream from the gas turbine is not, as previously, a superheater heating surface that is uncooled during the start-up process, but a continuously cooled evaporator heating surface, the gas turbine can be started up with full gradient even with a cold boiler, resulting in a corresponding reduction in start-up time. Rapid shutdown of the power plant is possible with significantly less stress on the boiler, as the superheater heating surface is either absent or preferably located between the evaporator heating surfaces. This prevents it from coming into contact with cold exhaust gas / air during and immediately after shutdown, thus eliminating the potential for "quenching" of the superheater heating surface. The high-temperature area (H2-O2 reactor, steam turbine inlet including valves, connecting piping) is spatially limited and is therefore particularly suitable for keeping the plant warm during shutdown using heating mats.The steam turbine can thus be started up very early, which is helped by the fact that the temperature of the fresh steam entering the steam turbine can be very precisely controlled via the H2-O2 reactor. The ability to adjust the temperature via the H2-O2 reactor and control the amount of water injected into it offer additional, very fast-acting load control options (also with regard to overload).

[0038] Overall, the previously rather sluggish steam section now operates at a similar speed to the gas turbine and can contribute to increasing the power plant's output even without the latter. This can also have a very positive effect, especially during retrofitting, since the choice of an open gas turbine process was often originally motivated by the associated flexibility.

[0039] Another important advantage of this concept compared to fully or partially hydrogen-fired gas turbines and the resulting combined cycle power plants with conventional steam cycles, as well as all other processes that burn hydrogen with atmospheric oxygen, is that the water produced by the reaction of hydrogen and oxygen is not lost into the atmosphere. This valuable resource, especially in times of water scarcity, remains available for further use. A further advantage over the aforementioned processes that use atmospheric oxygen for hydrogen combustion is that, due to the absence of nitrogen, no nitrogen oxides are produced and released into the atmosphere.

[0040] The invention is described in more detail below with reference to the figures, in which: Figure 1: An inventive device for generating electrical energy from hydrogen and oxygen Figure 2 : A compilation of several further developments of the device according to the invention Figure 3 : A further development of the device according to the invention with separate preheaters Figure 4 : A further development of the device according to the invention with a continuous steam generator

[0041] Figure 1shows the device 1 according to the invention for generating electrical energy from hydrogen and oxygen. The device comprises a gas turbine 2, a heat recovery steam generator 4 connected to the exhaust gas duct 3 of the gas turbine, an H 2 -O 2 reactor 6 and a steam turbine 11. The gas turbine 2 and the heat recovery steam generator 4 are conventional components. The gas turbine 2 can be fired entirely with hydrogen or partially with hydrogen and natural gas. The heat recovery steam generator 4 is designed such that it has only one pressure stage 5 and supplies slightly superheated steam. Steam 7 from the heat recovery steam generator 4, oxygen 8, hydrogen 9 and water 31 can be fed to the H 2 -O 2 reactor 6 via separate lines.

[0042] The H2-O2 reactor is designed to allow a reaction of oxygen 8 and hydrogen 9 to form steam 10. This reaction produces steam as a combustion product. The steam 10 is highly superheated (a permissible steam temperature is set by adding steam 7 and water 31) and is fed to the steam turbine 11 via a steam line 10. The steam turbine 11 is connected to a generator 12, which can provide electrical power. The steam produced by the reaction of hydrogen and oxygen, which is under high pressure and temperature, is thus introduced into the steam cycle and can be used as a circulating medium down to the level defined in the condenser. Due to the better heat utilization, the exhaust gas temperature at the chimney outlet can be lower.By using hydrogen in the steam cycle, the efficiency related to this fuel mass flow can be significantly increased compared to its use in the gas turbine.

[0043] Figure 2 shows several further developments of the device according to the invention. The further developments can be implemented in combination or separately.

[0044] For targeted control of the reaction and power increase in the H2-O2 reactor 6, feedwater 13 from the heat recovery steam generator 4 is injected into the H2-O2 reactor 6 via a line 19. The feedwater 13 can be high-pressure feedwater 14, which is advantageously taken from the outlet of the economizer 15 of the heat recovery steam generator 4.

[0045] To further increase efficiency, Figure 2In addition, a condensate preheater 20 is provided, which is connected upstream of the heat recovery steam generator 4 for preheating feedwater 13. The condensate preheater 20 is heated with steam taken from one or more taps 21 on the steam turbine 11.

[0046] In order to be able to increase the fresh steam temperature when required (e.g. when the H 2 -O 2 reactor is out of operation) to such an extent that moisture is avoided at the outlet of the steam turbine 11, Figure 2 Furthermore, an electrically operated superheater 22 is provided, which is connected upstream of the H 2 -O 2 reactor 6. The electrically operated superheater 22 makes it possible to ensure continued operation of the H 2 -O 2 reactor even without a hydrogen / oxygen supply.

[0047] To avoid potential delays during the start of gas turbine 2, Figure 2A superheater 27 is provided, which is arranged between the heating surfaces 23 of the first evaporator 25 and the second evaporator 26. This offers the advantage that the gas turbine 2 can always be started up with the full gradient, even if the heat recovery steam generator 4 is depressurized and the superheater 27 is still dry, and thus uncooled.

[0048] Figure 3 is based on the inventive design according to Figure 1 . Figure 3 shows a further development of the device according to the invention with separate preheaters 30, which are connected to taps on the steam turbine 11.

[0049] Figure 4 is largely based on Figure 1 . Figure 4shows a further development of the device according to the invention with a once-through steam generator 16 and a desuperheater 17. If very high live steam pressures and temperatures are selected, it is advantageous to design the heat recovery steam generator 4 as a once-through boiler instead of as a natural circulation (drum) boiler. The desuperheater 17 is designed as a heat exchanger 18 which, for energy absorption, is connected on the primary side to the steam line 10 between the steam turbine 11 and a condenser 24 downstream of the steam turbine 11, and for heat dissipation, is connected on the secondary side to the line 19 for supplying feedwater from the heat recovery steam generator 4 to the H 2 -O 2 reactor 6. The desuperheater 17 is required when very high live steam parameters of, for example, 1300°C and 150 bar pressure are generated with the H 2 -O 2 reactor 6.At the outlet of the steam turbine 11 there is still highly superheated steam, which is desuperheated by the desuperheater 17 before it is condensed in the condenser 24.

Claims

1. Apparatus (1) for generating electrical energy from hydrogen and oxygen, comprising an internal combustion engine (2), especially a gas turbine, a waste heat steam generator (4) connected to the exhaust gas duct (3) of the internal combustion engine (2), where the waste heat steam generator (4) has only one pressure stage (5), a steam turbine (11), a generator (12) connected to the steam turbine (11), and a conduit (19), characterized in that an H2-O2 reactor (6) is also provided, which can be fed with steam (7) from the waste heat steam generator (4), water (31), oxygen (8) and hydrogen (9), such that, in the H2-O2 reactor (6), with supply of steam (7), a reaction of oxygen (8) and hydrogen (9) to give steam (10) is achievable, in which the water (31) introduced evaporates, wherein additional steam is generatable, wherein the resulting greatly superheated steam (10) can be fed to the steam turbine (11), and the generator (12) connected to the steam turbine (11) can provide an electrical power, wherein, for control of the reaction in the H2-O2 reactor (6) and for adjustment of the steam exit temperature from the H2-O2 reactor, high-pressure feed water (14) from the waste heat steam generator (4) can be sprayed into the H2-O2 reactor (6) via the conduit (19).

2. Apparatus (1) according to Claim 1, characterized in that a heat remover (17) is also provided and is designed as a heat exchanger (18) which is connected on the primary side to the steam conduit (10) between the steam turbine (11) and a condenser (24) connected downstream of the steam turbine (11), and is connected on the secondary side to the conduit (19).

3. Apparatus (1) according to either of the preceding claims, characterized in that a condensate preheater (20) is also provided and is connected upstream of the waste heat steam generator (4) for preheating of feed water (13), wherein, in order to increase efficiency, steam can be withdrawn from one or more taps (21) on the steam turbine (11) and can be fed to the condensate preheater (20).

4. Apparatus (1) according to any of the preceding claims, characterized in that the evaporation pressure in the waste heat steam generator (4) is set only sufficiently high that, depending on the fresh steam temperature set via the H2-O2 reaction, wetness at the exit from the steam turbine (11) is avoided even without intermediate superheating.

5. Apparatus (1) according to any of the preceding claims, characterized in that an electrically operated superheater (22) is also provided and is connected upstream of the H2-O2 reactor (6), and by means of which the fresh steam temperature of the steam when the H2-O2 reactor is not in operation can be increased to such an extent that wetness is avoided at the exit from the steam turbine (11).

6. Apparatus according to any of the preceding claims, characterized in that the waste heat steam generator (4) has heating surfaces (23) that form a first evaporator (25) and a second evaporator (26), and heating surfaces (23) that form a first superheater (27), wherein the first superheater (27) is disposed between the heating surfaces (23) of the first evaporator (25) and of the second evaporator (26), so as to avoid any potential delay on startup of the gas turbine (2).

7. Method for generating electrical energy from hydrogen and oxygen, comprising an internal combustion engine (2), especially a gas turbine, a waste heat steam generator (4) which is connected to the exhaust gas duct (3) of the internal combustion engine (2) and has only one pressure stage (5), a steam turbine (11), a generator (12) connected to the steam turbine, and a conduit (19), wherein an H2-O2 reactor (6) is also provided, which is fed with steam (7) from the waste heat steam generator (4), water (31), oxygen (8) and hydrogen (9), such that, in the H2-O2 reactor (6), oxygen (8) and hydrogen (9) are reacted to give steam (10), and further steam is formed by the evaporation of the water (31) injected, wherein the steam is fed to the steam turbine (11), and the generator (12) connected to the steam turbine (11) generates an electrical power, and the reaction in the H2-O2 reactor (6) and the steam temperature at the exit from the H2-O2 reactor (6) are controlled by spraying high-pressure feed water (14) as water (31) from the waste heat steam generator (4) into the H2-O2 reactor (6) via the conduit (19).

8. Method according to Claim 7, wherein the steam circuit comprises a heat remover (17) designed as a heat exchanger (18) which is connected on the primary side to the steam conduit between the steam turbine (11) and a condenser (24) connected downstream of the steam turbine (11), in order to absorb heat, and is connected on the secondary side to the conduit (13), in order to release heat.

9. Method according to either of Claims 7 and 8, further comprising a condensate preheater (20) which is connected upstream of the waste heat steam generator (4) and by which feed water (13) is preheated, wherein, in order to increase efficiency, steam is withdrawn from one or more taps (21) on the steam turbine (11) and is fed to the condensate preheater (20).

10. Method according to any of Claims 7 to 9, wherein the evaporation pressure in the waste heat steam generator (4) is set only sufficiently high that, depending on the fresh steam temperature set via the H2-O2 reaction, wetness at the exit from the steam turbine (11) is avoided even without intermediate superheating.

11. Method according to any of Claims 7 to 10, further comprising an electrically operated superheater (22) which is connected upstream of the H2-O2 reactor (6), and by means of which the fresh steam temperature of the steam when the superheater (22) is not in operation can be increased to such an extent that wetness is avoided at the exit from the steam turbine (11).

12. Method according to any of Claims 7 to 11, wherein the waste heat steam generator (4) has heating surfaces that form a first evaporator (25) and a second evaporator (26), and heating surfaces (23) that form a first superheater (27), wherein the first superheater (27) is disposed between the heating surfaces (23) of the first evaporator (25) and of the second evaporator (26), so as to avoid any potential delay on startup of the gas turbine (2).