IT202200026685A1 - Gas turbine auxiliary system for NH3 conditioning - Google Patents

Description

Gas turbine auxiliary system for NH3 conditioning

Description

TECHNICAL FIELD

The present disclosure relates to a system for generating power using a gas turbine, wherein the system comprises an ammonia cracking device. The embodiments described herein specifically relate to a gas turbine auxiliary system for NH3 conditioning, wherein a fuel skid processes an incoming ammonia stream to provide an NH3/H2/N2 gas mixture that allows the gas turbine to be operated under all conditions. Also described herein are methods for optimizing gas turbine operation and controlling NOx emissions from the gas turbine under all gas turbine conditions.

BACKGROUND OF THE TECHNIQUE

Gas turbines are commonly used to generate power in power plants by burning fuel in them. Specifically, the basic operation of a gas turbine is a Brayton cycle with air as the working fluid: atmospheric air passes through a compressor which brings it to a higher pressure; energy is then added by injecting fuel into the air in a combustion chamber and igniting it so that a combustion generates a high-temperature flow; this high-temperature, pressurized gas enters a turbine, producing shaft work output in the process, used to drive the compressor; unused energy escapes in the exhaust gas which can be reused for external work, such as directly producing thrust in a turbojet engine, or rotating a second independent turbine (known as a power turbine) which can be connected to a fan, propeller or electric generator. The purpose of the gas turbine determines the design to achieve the most desirable split of energy between thrust and shaft work. The fourth stage of the Brayton cycle (cooling of the working fluid) is omitted, as gas turbines are open systems that do not reuse the same air.

Commonly used fuels include natural gas, propane, diesel, biogas and biodiesel. One of the major problems associated with burning fuels such as these in gas turbines is the resulting production of carbon dioxide (CO2) gas. Rising levels of CO2 in the atmosphere are harmful to the environment and are a known cause of global warming. As such, there is a need to provide fuels for use in gas turbines that do not generate CO2 during combustion, or from which CO2 must be removed prior to combustion.

Carbon-free fuels include ammonia and hydrogen. However, both ammonia and hydrogen have some problems associated with their direct use as a fuel in a gas turbine. The main problem associated with the direct use of ammonia as a fuel in gas turbines is that during the combustion process, ammonia is oxidized to nitrogen oxides (NOx), a pollutant that contributes to acid rain and global warming. Furthermore, due to the low heat content and low reactivity of ammonia with oxygen, the combustion of ammonia in the gas turbine has stability (blow-out) problems over the entire range of gas turbine operating conditions. On the other hand, although the combustion of hydrogen still produces NOx pollutants, the stability (blow-out) problems disappear. However, a number of problems are associated with the use of hydrogen as a fuel, including storage problems and the fact that hydrogen is an extremely flammable gas. The availability of N2 as an inert material within the combustion process could contribute to reducing NOx emissions depending on the type of flame created in the gas turbine combustor.

CN107288780A describes a system for generating power using a gas turbine, where ammonia is used as a fuel. Upstream of the combustion chamber, ammonia is partially decomposed to generate hydrogen in an ammonia cracking device to provide a fuel mixture containing hydrogen and ammonia. Since the fire point of hydrogen is lower than that of ammonia, hydrogen is first burned in the combustion chamber to release heat to ignite ammonia in the combustion chamber. As a result, hydrogen can accelerate the combustion process, and as a result, the combustion performance of ammonia fuel is improved. In conclusion, the amount of hydrogen supplied is functional for the ignition of NH3. However, the system described in CN107288780 does not completely solve the environmental problems due to the formation of nitrogen oxides due to the oxidation of ammonia during the combustion process. US11084719B2 discloses a process for generating power using a gas turbine, comprising the steps of: (i) vaporizing and preheating liquid ammonia to produce preheated ammonia gas; (ii) introducing the preheated ammonia gas into an ammonia cracker to convert the ammonia gas into a mixture of hydrogen and nitrogen; (iii) converting the preheated ammonia gas into a mixture of hydrogen and nitrogen in the cracker; (iv) cooling the mixture of hydrogen and nitrogen to give a cooled mixture of hydrogen and nitrogen; (v) introducing the cooled mixture of hydrogen and nitrogen into a gas turbine; and (vi) burning the cooled mixture of hydrogen and nitrogen in the gas turbine to generate power. US11084719B2 also discloses embodiments wherein the composition of the mixture of hydrogen and nitrogen exiting the ammonia cracker can be adjusted by purification techniques. However, the composition of the mixture exiting the cracking process may be far from optimal for the operational requirements of the GT.

US11156168B2 discloses a gas turbine system that is equipped with a gas turbine, a heater, a decomposition gas line, and a decomposition gas compressor. The heater heats ammonia and thermally decomposes it to convert the ammonia to decomposition gas comprising hydrogen gas and nitrogen gas. The decomposition gas line delivers the decomposition gas from the heater to the gas turbine. The decomposition gas compressor increases the pressure of the decomposition gas to a pressure equal to or greater than a supply pressure at which the decomposition gas can be supplied to the gas turbine. US11156168B2 also discloses a control device that regulates the ratio of the flow rate of the decomposition gas to the flow rate of the entire fuel gas (which includes natural gas and decomposition gas). Controlling this ratio allows a mixture of decomposition gas and natural gas to be obtained and regulated to the combustion chamber. However, natural gas combustion still produces a high level of carbon dioxide, which is released into the atmosphere or requires additional carbon capture systems. In conclusion, the prior art solution approaches negatively affect the operating costs of the system or have a negative environmental impact. Therefore, an improved system that generates power using a gas turbine and ammonia as fuel to address the problems of real-time conditioning of NH3 to achieve a NH3/H2/N2 gas mixture that allows the gas turbine to operate under any conditions would be beneficial and welcome in the technology. The conditioning of NH3 needs to be flexibly pursued and adjusted at different levels along the way to the turbine, so there is a need for a system that can adjust and supply fuels to the gas turbine at different stages, to improve performance but also reduce NOx emissions. More generally, it would be desirable to provide suitable methods and systems to address the real-time conditioning of NH3 to achieve a NH3/H2/N2 gas mixture that allows the gas turbine to operate under any conditions. efficiently solve the problems related to the supply of an auxiliary NH3 conditioning system to produce a NH3/H2/N2 gas mixture that allows the gas turbine to operate under any conditions.

SUMMARY

In one aspect, the subject matter described herein is directed to an improved system that generates power utilizing a gas turbine and ammonia as a fuel wherein the system comprises an ammonia cracking device. The embodiments described herein specifically relate to a gas turbine auxiliary system for NH3 conditioning wherein a fuel skid processes an incoming ammonia stream to provide an NH3/H2/N2 gas mixture that permits operation of the gas turbine under all conditions.

In another aspect, the subject matter herein is directed to a method of generating power using a gas turbine and ammonia as fuel. The auxiliary ammonia conditioning system is operated by control routines depending on the GT parameters, combustion parameters and NOx requirements at the GT exhaust.

BRIEF DESCRIPTION OF THE DRAWINGS

A fuller appreciation of the disclosed embodiments of the invention and of many of the advantages thereof will be readily obtained as they become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which: FIG. 1 illustrates a schematic diagram of a power generation system utilizing a gas turbine and including an ammonia cracking device in accordance with a first embodiment;

Figure 2 illustrates a block diagram of the control architecture of the power generation system of Figure 1;

Figure 3 illustrates a schematic diagram of a power generation system using a gas turbine and including an ammonia cracking device according to a second embodiment;

Figure 4 illustrates a block diagram of the control architecture of the power generation system of Figure 3;

Figure 5 illustrates a schematic diagram of a power generation system using a gas turbine and including an ammonia cracking device according to a third embodiment;

Figure 6 illustrates a schematic diagram of a power generation system using a gas turbine and including an ammonia cracking device according to a fourth embodiment;

Figure 7 illustrates a schematic diagram of a power generation system using a gas turbine and including an ammonia cracking device according to a fifth embodiment; and

Figure 8 illustrates a schematic diagram of a power generation system using a gas turbine and including an ammonia cracking device according to a fifth embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In one aspect, the subject matter herein relates to a system for power generation using a gas turbine, wherein the system comprises an ammonia cracking device, for converting at least part of an NH3 stream into H2 and N2, to provide an NH3/H2/N2 gas mixture that allows the gas turbine to be operated under any conditions. In another aspect, the subject matter herein relates to a gas turbine auxiliary system for conditioning NH3 wherein an NH3 feed stream is split into two separate NH3 streams, a first NH3 stream is decomposed into H2 and N2 through a catalytic cracking reactor or a thermal cracking reactor to obtain a H2 and N2 stream, and a second NH3 stream is directed to a bypass line. In particular, downstream of the cracking reactor, the H2 and N2 stream can be decomposed into H2 and N2, and a second NH3 stream is decomposed into H2 and N2, and a second NH3 stream is decomposed into a H2 and N2 stream. be mixed together with the second NH3 stream, to obtain a NH3/H2/N2 gas mixture with a controlled ratio of NH3 on one side and H2 and N2 on the other. Optionally, downstream of the cracking reactor, the N2 can be separated from the H2 gas in the H2 and N2 stream, to obtain a NH3/H2/N2 gas mixture with a controlled ratio of NH3, H2 and N2 and to also allow the use of N2 as a purge gas.

Reference will now be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not as a limitation of the disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the scope or spirit of the disclosure. Reference throughout the disclosure to “an embodiment” or “some embodiments” means that the particular functionality, structure or feature described in connection with an embodiment is included in at least one embodiment of the disclosed subject matter. Accordingly, the appearance of the phrase “in an embodiment” or “in some embodiments” at various points in the disclosure does not necessarily refer to the same embodiment. Furthermore, the particular functionality, structure or feature may be combined in any suitable manner in one or more embodiments.

When introducing elements of various embodiments, the terms “a,” “an,” “the,” and “said” are intended to indicate that one or more of the elements are present. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements in addition to the elements listed.

Referring now to the drawings, FIG. 1 shows a schematic of an exemplary power generation system comprising a gas turbine 100. The gas turbine 100 comprises a compressor, a combustion chamber, and an expander. The gas turbine 100 is fed by a flow of NH3/H2/N2 gas mixture and a flow of NH3 gas. The flow of the NH3/H2/N2 gas mixture is directed to the primary stage of the gas turbine 100 through a gas turbine feed line 1, and the flow of NH3 gas is directed to the secondary stage of the gas turbine 100 through a NH3 gas feed flow line 2.

Furthermore, a gas turbine auxiliary system for conditioning NH3 is disposed upstream of the gas turbine 100, the gas turbine auxiliary system including a NH3 heater/vaporizer/pressurizer 200, for heating and then vaporizing a stream of liquid NH3 from an NH3 flow line 4, and a cracking reactor 300, which is connected to the NH3 heater/vaporizer/pressurizer via a gas outlet line 5 of the NH3 heater/vaporizer/pressurizer and a feed line 6 of the cracking reactor. In alternative exemplary embodiments, the NH3 heater/vaporizer/pressurizer is composed of shell and tube heat exchangers or plate heat exchangers. In some embodiments, a heat transfer fluid of the heater/vaporizer/pressurizer is provided. the exhaust gas of the gas turbine or another intermediate fluid (such as steam or thermal oil). According to one embodiment, the heat exchanger is made in two stages, one to heat and vaporize the liquid ammonia, the other to restore the initial pressure or optionally increase the pressure of the ammonia gas. In some embodiments, the heater/vaporizer/pressurizer system also includes a storage tank for the high-pressure ammonia gas.

According to an embodiment shown in figure 1, the NH3 300 cracking reactor is a catalytic or thermal reactor, configured to process ammonia and dissociate it at least into its basic components, i.e. hydrogen and nitrogen, in the presence of a catalyst or under temperature control, according to the reaction:

The hydrogen-nitrogen mixture and possibly any unreacted ammonia present resulting from the cracking reaction is then directed to the gas turbine 100 via an outlet line 7 of the NH3/H2/N2 gas mixture flow, connected downstream of the gas turbine feed line 1.

A bypass flow of NH3 is separated from the NH3 gas flow from the heater/vaporizer/pressurizer via a bypass flow line 11 of the NH3 gas, which is connected upstream to the outlet gas line 5 of the heater/vaporizer/pressurizer and which is connected downstream to the NH3 gas feed flow line 2 of the gas turbine 100, in particular to the secondary stage of the gas turbine 100.

The system allows the gas turbine control circuit to control the ratio of NH3 to be burned together with H2 and N2 from the cracking reactor, based on the operational needs of the gas turbine.

Exhaust gas from the gas turbine 100 is routed to an exhaust gas flow line 15, from which a portion of the exhaust gas flow is split through an exhaust gas heat recovery line 12, which is routed to the cracking reactor 300 and/or the NH3 heater/vaporizer/pressurizer 200. Referring to FIG. 1, the exhaust gas heat recovery line 12 is divided into a first heat recovery line 13, which is routed to the cracking reactor 300, and a second heat recovery line 14, which is routed to the NH3 heater/vaporizer/pressurizer 200. An emergency system (not shown) is arranged along the gas turbine feed line 1, including a vent and emergency valves to prevent overpressure.

The auxiliary gas turbine system for NH3 conditioning of Figure 1 operates as follows. The system is started by heating/vaporizing/pressurizing liquid ammonia in the NH3 heater/vaporizer/pressurizer 200 which is fed in gaseous state to the NH3 cracking reactor 300. Part of the gaseous ammonia from the NH3 heater/vaporizer/pressurizer 200 is poured into the NH3 gas bypass flow line 11 and is directed to the gas turbine 100 via the NH3 gas feed flow line 2. Some of the heat produced by the gas turbine 100 is sent to the NH3 heater/vaporizer/pressurizer 200 and the NH3 cracking reactor 300. Additional liquid ammonia is heated, vaporized, and pressurized in the vaporizer/pressurizer 200, and the NH3 cracking reactor 300 begins operations by feeding the gas mixture into the outlet line 7 of the NH3/H2/N2 gas mixture flow. A storage drum (not shown) may optionally be arranged along the outlet line 7 of the NH3/H2/N2 gas mixture flow. When the pressure in the outlet line 7 of the NH3/H2/N2 gas mixture flow reaches a threshold value, the gas turbine start-up sequence may begin. Gas turbine ignition is achieved by using the flows fed via gas turbine feed line 1 or NH3 gas feed flow line 2 as fuel, receiving a flow of NH3 gas from NH3 gas bypass flow line 11. If energy to start the NH3 heater/vaporizer/pressurizer 200 and the NH3 cracking reactor 300 is not available, a starting fuel such as natural gas may be connected to gas turbine feed line 1 or NH3 gas feed flow line 2 and used to start and ramp up the gas turbine to end-of-sequence or full no-load gas turbine speed condition. Once the gas turbine is started, the heat from the exhaust gases begins to provide energy to both the NH3 200 heater/vaporizer/pressurizer, which heats, vaporizes and pressurizes the liquid ammonia to a gaseous state, and the NH3 300 cracking reactor, which decomposes the gaseous ammonia into a mixture of hydrogen, nitrogen and any unreacted ammonia. Once the appropriate mixture is created, the flow of the NH3/H2/N2 gas mixture into the gas turbine feed line 1 is controlled according to the gas turbine control programs. During all gas turbine sequences (ramp-up, load operations, normal shutdown) a unit The auxiliary gas turbine control unit 37 manages the composition requirements of the residual hydrogen, nitrogen and ammonia mixture of gas turbine feedline 1 by acting on the parameters of the NH3 cracking reactor 300 and managing the flow ratio between gas turbine feedline 1 and NH3 gas feedline 2. The NH3 cracking reactor parameters managed by the auxiliary gas turbine control unit 37 are highly dependent on the NH3 cracking reactor technology. In some embodiments, the NH3 cracking reactor parameters include the temperature of the reacting ammonia gas in specific sections of the reactor (e.g., in the inlet section) and the recycle ratio of the NH3 cracking reactor. The emergency shutdown of gas turbine 100 allows for immediate isolation of the auxiliary gas turbine system for NH3 conditioning from gas turbine 100 and de-energization of the NH3 heater/vaporizer/pressurizer 200 and the NH3 cracking reactor 300 according to its specific safety requirements.

The operation of the auxiliary gas turbine NH3 conditioning system of Figure 1 is controlled through a plurality of control valves operated in accordance with a control method which will be explained below. A gas flow valve 21 is disposed along gas turbine feed line 1, to control the flow of the NH3/H2/N2 gas mixture into gas turbine feed line 1. A NH3 gas bypass flow valve 22 is disposed along NH3 gas feed line 2, downstream of NH3 gas bypass flow line 11, to control the flow of the NH3 gas bypass flow to the gas turbine 100, and conversely the flow of the NH3 gas to the cracking reactor 300 via the cracking reactor feed line 6. Finally, on the first heat recovery valve 13 is disposed. a heat recovery flow valve 26 is arranged to control the portion of the exhaust gas from the gas turbine 100 that is directed to the NH3 cracking reactor 300 and vice versa the portion of the exhaust gas directed to the NH3 heater/vaporizer/pressurizer 200. The gas flow valve 21, the NH3 gas bypass flow valve 22 and the heat recovery flow valve 26 may be electrically operated valves, pneumatically operated valves or hydraulically operated valves.

Still referring to Figure 1, according to the block diagram of the control architecture of the power generation system shown in Figure 2, the flow valves 21 and 22 and the heat recovery flow valve 26 are operated as follows. A control unit of the gas turbine 30, such as a computer or a programmable logic controller (PLC), receives the following input parameters: gas turbine parameters 31, combustion parameters 32 and NOx requirements 33. In particular, the gas turbine parameters 31 are dependent on the gas turbine technology. In some embodiments, the gas turbine parameters 31 include the power generated by the gas turbine, the speed of the gas turbine, the temperature of the gas turbine exhaust gas. The combustion parameters 32 are dependent on the combustion technology adopted by the gas turbine. In some embodiments, the combustion parameters 32 include the fuel-air ratio in specific regions of the combustor, the heat load distribution along the combustor, and the NOx and NH3 flow at the combustor exit. The NOx requirements 33 include the NOx exhaust gas emissions in the exhaust stream downstream of the gas turbine. The total amount of gas supplied to the gas turbine via gas turbine feed line 1 (denoted m1) and NH3 gas feed line 2 (m2) are a function of the above gas turbine parameters:

m1 m2 = f(GT parameters)

The volumetric composition of the NH3/H2/N2 gas mixture flow in the gas turbine feed line 1 (denoted by reference number 34 in Figure 2); the ratio 35 of the mass flow of NH3 gas via the NH3 gas feed line 2 (m2) and the total mass flow (m1+m2) of the NH3/H2/N2 gas mixture flow via the gas turbine feed line 1 (m1) and the NH3 gas feed flow to the gas turbine via the NH3 gas feed line 2 (m2) are a function of the combustion parameters and NOx requirements above: x1i = f(combustion parameters; NOx requirements) m2/(m1 m2) = f(combustion parameters; NOx requirements)

These parameters are the input or inputs to the auxiliary control unit 37 such as a computer or programmable logic controller (PLC), configured to control the operation of the flow valves 21 and 22 and the heat recovery flow valve 26 according to the following relationships. The operation Y21 of the gas flow valve 21 which controls the amount of NH3/H2/N2 gas mixture flow flowing into the gas turbine feed line 1 is a function of the total amount of gas flow m1 fed to the gas turbine via the gas turbine feed line 1 and the NH3 gas feed flow m2 fed to the gas turbine via the NH3 gas feed line 2:

Y21 = f(m1 m2)

The operation Y22 of the NH3 gas bypass flow valve 22 is a function of the ratio 35 of the NH3 gas mass flow m2 via the NH3 gas feed flow line 2 and the total mass flow of the NH3/H2/N2 gas mixture flow m1 via the gas turbine feed line 1 and the NH3 gas feed flow m2 to the gas turbine via the NH3 gas feed line 2:

Y22 = f(m2/(m1 m2))

Finally, the operation of the heat recovery flow valve 26 is a function of the volumetric composition of the gas:

Y26 = f(x1i)

The control method described above allows the composition of the fuel to be changed in the gas turbine and ammonia to be injected in any ratio according to any requirements of the combustor and gas turbine (these requirements not being part of this description).

Continuing to refer to FIG. 1 and FIG. 2, FIG. 3 shows a schematic of an exemplary power generation system according to a second embodiment. The gas turbine 100 includes a compressor, a combustion chamber, and a turbine. The gas turbine 100 is powered by a flow of NH3/H2/N2 gas mixture, a flow of NH3 gas, and a flow of N2 gas. The flow of NH3/H2/N2 gas mixture is directed to the primary gas turbine stage of the gas turbine 100 through a gas turbine feed line 1, the flow of NH3 gas is directed to the secondary gas turbine stage of the gas turbine 100 through a NH3 gas feed flow line 2, and the flow of N2 gas is directed to the secondary gas turbine stage of the gas turbine 100 through a N2 gas feed flow line 3. Furthermore, a gas turbine auxiliary system for conditioning NH3 is provided upstream of the gas turbine 100, the gas turbine auxiliary system comprising an NH3 heater/vaporizer/pressurizer 200, for heating and then vaporizing a liquid NH3 stream from an NH3 flow line 4, and a cracking reactor 300, which is connected to the NH3 heater/vaporizer/pressurizer via an NH3 heater/vaporizer/pressurizer gas outlet line 5 and a cracking reactor feed line 6. In this embodiment, the hydrogen and nitrogen mixture and unreacted ammonia resulting from the cracking reaction is treated to separate an NH3/H2/N2 gas mixture stream and an N2 gas mixture stream. The NH3/H2/N2 gas mixture stream from the cracking reactor 300 is separated into two gas streams. directed to the gas turbine 100 through an outlet line 7 of the NH3/H2/N2 gas mixture flow, connected downstream of the gas turbine feed line 1.

Nitrogen separation can be achieved through various technologies. In one exemplary embodiment, the NH3300 cracking reactor is a membrane reactor, which operates as follows. A membrane separates the reactor into two separate sections. A first section is directly connected to feed line 6 of the cracking reactor. Inside the first section, ammonia fed to the membrane reactor is reacted. A fraction of nitrogen resulting from the cracking reaction permeates the membrane and passes to a second section of the membrane reactor, separating from hydrogen, unreacted ammonia and a remaining fraction of nitrogen, which remains inside the first section of the membrane reactor.

The N2 gas flow from the cracking reactor 300 is directed to the gas turbine 100 via an N2 gas flow outlet line 8, connected downstream of the N2 gas feed flow line 3. A fraction of the N2 gas flow from the cracking reactor 300 may be separated and returned to the NH3/H2/N2 gas blend flow outlet line 7 via an N2 gas bypass line 9, to control the composition of the NH3/H2/N2 gas blend flow to the gas turbine 100 via gas turbine feed line 1.

An NH3 bypass flow is split (separated) from the NH3 gas flow from the heater/vaporizer/pressurizer via an NH3 gas bypass flow line 11, which is connected upstream to the heater/vaporizer/pressurizer gas outlet line 5 and which is connected downstream to the NH3 gas feed flow line 2 of the gas turbine 100, specifically to the gas turbine secondary stage of the gas turbine 100.

The composition of the NH3/H2/N2 mixture flow directed to the gas turbine 100 via gas turbine feed line 1 is also controlled by mixing the NH3/H2/N2 gas mixture stream with ammonia. For this purpose, a separate NH3 gas bypass flow is taken from the NH3 gas bypass flow via a separate NH3 gas bypass flow line 10, which is connected upstream of the NH3 gas bypass flow line 11 and downstream of the NH3/H2/N2 gas mixture flow outlet line 7.

The system allows the gas turbine control circuit to control the ratio of NH3 to be burned together with H2 and N2 from the cracking reactor, based on the operational needs of the gas turbine.

Exhaust gas from the gas turbine 100 is directed to an exhaust gas flow line 15, from which a portion of the exhaust gas flow is separated via an exhaust gas heat recovery line 12, which is directed to the cracking reactor 300 and/or the NH3 heater/vaporizer/pressurizer 200. Referring to FIG. 3, the exhaust gas heat recovery line 12 is divided into a first heat recovery line 13, which is directed to the cracking reactor 300, and a second heat recovery line 14, which is directed to the NH3 heater/vaporizer/pressurizer 200. An emergency system (not shown) is arranged along the gas turbine feed line 1, comprising a vent and emergency valves to prevent overpressure.

The auxiliary gas turbine system for NH3 conditioning of Figure 3 operates as follows. The system is started by heating/vaporizing/pressurizing liquid ammonia inside the NH3 heater/vaporizer/pressurizer 200 which is fed in gaseous state to the NH3 cracking reactor 300. Part of the gaseous ammonia from the NH3 heater/vaporizer/pressurizer 200 is poured into the NH3 gas bypass flow line 11 and is directed to the gas turbine 100 via the NH3 gas feed flow line 2. Some of the heat produced by the gas turbine 100 is sent to the NH3 heater/vaporizer/pressurizer 200 and the NH3 cracking reactor 300. Additional liquid ammonia is heated, vaporized, and pressurized in the vaporizer/pressurizer 200, and the NH3 cracking reactor 300 begins operations by feeding the gas mixture into the outlet line 7 of the NH3/H2/N2 gas mixture flow. A storage drum (not shown) may optionally be arranged along the outlet line 7 of the NH3/H2/N2 gas mixture flow. When the pressure in the outlet line 7 of the NH3/H2/N2 gas mixture flow reaches a threshold value, the gas turbine start-up sequence may begin. Gas turbine ignition is achieved by using the flows fed via gas turbine feed line 1 or NH3 gas feed flow line 2 as fuel, receiving a flow of NH3 gas from NH3 gas bypass flow line 11. If energy to start the NH3 heater/vaporizer/pressurizer 200 and the NH3 cracking reactor 300 is not available, a starting fuel such as natural gas may be connected to gas turbine feed line 1 or NH3 gas feed flow line 2 and used to start and ramp up the gas turbine to end-of-sequence or full no-load gas turbine speed condition. Once the gas turbine is switched on, the heat from the exhaust gases begins to provide energy to both the NH3 200 heater/vaporizer/pressurizer that heats, vaporizes and pressurizes the liquid ammonia to a gaseous state and the NH3 300 cracking reactor that decomposes the gaseous ammonia into a mixture of hydrogen, nitrogen and unreacted ammonia. Once the appropriate mixture is created, the flow of the NH3/H2/N2 gas mixture inside the gas turbine feed line 1 is controlled according to gas turbine control programs. During all gas turbine sequences (ramp-up, loading operations, normal shutdown) a gas turbine control system manages the composition requirements of the residual hydrogen, nitrogen and ammonia mixture of gas turbine feedline 1 by acting on the NH3300 cracking reactor parameters and managing the flow ratio between gas turbine feedline 1 and NH3 gas feedline 2. Emergency gas turbine shutdown allows immediate isolation of the gas turbine auxiliary system for NH3 conditioning from the gas turbine and de-energization of the NH3 200 heater/vaporizer/pressurizer and the NH3 300 cracking reactor according to its specific safety requirements. The NH3300 cracking reactor also separates nitrogen from the unreacted hydrogen, nitrogen and ammonia gas mixture and then provides a stream of N2 in the N2 gas flow outlet line 8, which can be used for various applications, such as N2 storage or gas turbine blowdown services.

The operation of the auxiliary system of the gas turbine for conditioning NH3 of Figure 3 is controlled through a plurality of control valves operated in accordance with a control method which will be explained below. A gas flow valve 21, specifically a valve 21, is arranged along the gas turbine feed line 1 to control the flow of the NH3/H2/N2 gas mixture into the gas turbine feed line 1. An NH3 gas bypass flow valve 22 is arranged along the NH3 gas bypass flow line 11 to control the flow of the NH3 gas bypass flow to the gas turbine via the NH3 gas feed flow line 2, and vice versa the flow of the NH3 gas flow to the cracking reactor 300 via the cracking reactor feed line 6. An NH3 gas bypass flow separation valve 23 is arranged along the NH3 gas bypass flow line 11 to control the flow of the NH3 gas bypass flow to the gas turbine via the NH3 gas feed flow line 2, and vice versa the flow of the NH3 gas flow to the cracking reactor 300 via the cracking reactor feed line 6. An NH3 gas bypass flow separation valve 24 is arranged along the NH3 gas bypass flow line 11 to control the flow of the NH3 gas bypass flow to the gas turbine via the NH3 gas feed line 2, and vice versa the flow of the NH3 gas flow to the cracking reactor 300 via the cracking reactor feed line 6. arranged along the NH3 gas bypass separation flow line 10 to control the amount of NH3 gas bypass flow directed to the NH3/H2/N2 gas mixture flow outlet line 7, to control the composition of the NH3/H2/N2 mixture flow directed to the gas turbine 100 via the gas turbine feed line 1. Arranged along the N2 gas bypass line 9 is an N2 gas bypass flow slide valve 24 to control the nitrogen flow of the N2 gas flow outlet line 8 from the NH3 cracking reactor 300 used to mix with the NH3/H2/N2 gas mixture flow directed to the gas turbine 100 via the gas turbine feed line 1. In addition, a gas turbine N2 feed flow slide valve 25 is an N2 gas bypass flow slide valve 26. arranged along the N2 gas feed flow line 3, to control the nitrogen flow of the N2 gas outlet flow line 8 from the NH3300 cracking reactor to the gas turbine 100. Finally, a heat recovery flow valve 26 is arranged on the first heat recovery outlet 13 to control the heat recovery flow portion of the exhaust gas from the gas turbine 100 that is directed to the gas turbine 100. directed to the NH3300 cracking reactor and vice versa the heat recovery flow part directed to the NH3 200 heater/vaporizer/pressurizer. The gas flow valve 21, the NH3 gas bypass flow slide valve 22, the NH3 gas bypass flow slide valve 23, the N2 gas bypass flow slide valve 24, the gas turbine N2 feed flow slide valve 25 and the heat recovery flow valve 26 may be electrically operated valves, pneumatically operated valves or hydraulically operated valves.

Referring again to Figure 3, according to the block diagram of the power generation system control architecture shown in Figure 4, the flow valves 21-25 and the heat recovery flow valve 26 are operated as follows. The input parameters to the gas turbine control unit 30 are the gas turbine parameters 31, the combustion parameters 32 and the NOx requirements 33. The total amount of gas fed to the gas turbine as the sum of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line 1, the NH3 gas feed flow line 2 and the N2 gas feed flow (m3) via the N2 gas feed flow line 3 is a function of the gas turbine parameters:

m1 m2 m3 = f(GT parameters) The volumetric composition of the NH3/H2/N2 gas mixture flow in the gas turbine feed line 1 (denoted by reference number 34 in Figure 2); the ratio 35 of the NH3 gas mass flow m2 via the NH3 gas feed line 2 and the total mass flow of the NH3/H2/N2 gas mixture flow m1 via the gas turbine feed line 1 and the NH3 gas feed flow m2 to the gas turbine via the NH3 gas feed line 2; and the ratio 36 of the N2 gas mass flow via N2 gas feed flow line 3 and the total mass flow of the NH3/H2/N2 gas mixture flow via gas turbine feed line 1 and the NH3 gas feed flow to the gas turbine via NH3 gas feed flow line 2 are a function of the combustion parameters and NOx requirements:

x1i = f(combustion parameters; NOx requirements) m2/(m1 m2) = f(combustion parameters; NOx requirements)

m3/(m1 m2) = f(combustion parameters; NOx requirements)

These parameters are the input of an auxiliary control unit 37, which controls the operation of the flow valves 21-25 and the heat recovery flow valve 26 according to the following relationships. The operation Y21 of the gas flow valve 21 which controls the flow amount of the NH3/H2/N2 gas mixture flowing into the gas turbine feed line 1, is a function of the total amount of gas fed to the gas turbine via the gas turbine feed line 1 (m1), the NH3 gas feed line 2 (m2) and the N2 gas feed line 3 (m3):

Y21 = f(m1 m2 m3)

The operation Y22 of the NH3 gas bypass flow valve 22 is a function of the ratio 35 of the NH3 gas mass flow via NH3 gas feed line 2 and the total mass flow of the NH3/H2/N2 gas mixture flow via gas turbine feed line 1 and the NH3 gas feed flow to the gas turbine via NH3 gas feed line 2:

Y22 = f(m2/(m1 m2))

The operation Y23 of the NH3 gas bypass separation flow valve 23 is a function of the volumetric composition of the NH3/H2/N2 gas mixture flow in the gas turbine feed line 1:

Y23 = f(x1i)

The operation Y24 of the N2 gas bypass flow valve 24 is also a function of the volumetric composition of the NH3/H2/N2 gas mixture flow in the gas turbine feed line 1:

Y24 = f(x1i)

The Y25 operation of the gas turbine N2 feed flow valve 25 is a function of the ratio 36 of the mass flow m3 of the N2 gas via the N2 gas feed flow line 3 and the total mass flow of the NH3/H2/N2 gas mixture flow via the gas turbine feed line 1 and the NH3 gas feed flow to the gas turbine via the NH3 gas feed flow line 2:

Y25 = f(m3/(m1 m2))

Finally, the operation of the heat recovery flow valve 26 is a function of the volumetric composition of the NH3/H2/N2 gas mixture flow in the gas turbine feed line 1:

Y26 = f(x1i)

The control method described above allows the composition of the fuel to be changed in the gas turbine and ammonia and nitrogen to be injected in any ratio according to any requirements of the combustor and gas turbine (these requirements not being part of this description).

For example: if the combustor requires a hydrogen-rich fuel but a large inert fluid (N2) to reduce flame temperatures and increase gas turbine power, then Case 1 of Table 1 below is applicable. If the combustor requires a hydrogen-rich fuel but a large separate ammonia injection, to optimize NOx emission, then Case 3 of Table 1 is applicable. If the combustor does not require large amounts of hydrogen, then Case 2 of Table 1 is applicable, i.e. large separated ammonia and large separated nitrogen.

Table 1

Continuing to refer to Figure 1, Figure 2, Figure 3 and Figure 4, Figure 5 illustrates a third embodiment of a power generation system using a gas turbine and including an ammonia cracking device. The same reference numbers indicate the same or corresponding parts, elements or components already illustrated in Figure 1, Figure 2, Figure 3 and Figure 4 and described above, and which will not be described again.

The embodiment shown in FIG. 5 differs from the embodiment of FIG. 3 in that at least part of the N2 gas flow from the cracking reactor 300 is not directed to the gas turbine 100, but is collected and used for other purposes. In this embodiment, the outlet line 8 of the N2 gas flow is connected downstream to an N2 gas tap line 3?. A flow valve 25? is disposed along the N2 gas tap line 3? to control the nitrogen flow from the outlet line 8 of the N2 gas flow from the NH3300 cracking reactor to external uses. The control method for this embodiment differs from that described with reference to FIG. 3 and FIG. 4 in that the actuation Y25 of the flow valve 25? is a function of needs that are not the subject of the present invention:

Y25? = f(other requirements)

Continuing to refer to Figure 1, Figure 2, Figure 3, Figure 4 and Figure 5, Figure 6 illustrates a fourth embodiment of a power generation system using a gas turbine and including an ammonia cracking device. The same reference numbers indicate the same or corresponding parts, elements or components already illustrated in Figure 1, Figure 2, Figure 3, Figure 4 and Figure 5 and described above, and which will not be described again.

The embodiment shown in Figure 6 differs from the embodiments of Figures 3 and 5 in that the injection points of the gas turbine feed line 1 and the NH3 gas feed flow line 2 are swapped. Swapping the injection points may be necessary to account for different combustion technologies that may be applied to the gas turbine with different flame evolution along the flow path within the combustor. In particular, according to this embodiment, the gas turbine feed line 1 is directed to the secondary gas turbine stage of the gas turbine 100 and the NH3 gas feed flow line 2 is directed to the primary gas turbine stage of the gas turbine 100. The control method for this embodiment is the same as described with reference to Figure 3 and Figure 4.

Furthermore, still with reference to Figures 1-6, Figure 7 illustrates a fifth embodiment of a power generation system using a gas turbine and comprising an ammonia cracking device. The same reference numbers indicate the same or corresponding parts, elements or components already illustrated in Figures 1-6 and described above, and which will not be described again. The embodiment shown in Figure 7 differs from the embodiments of Figures 3-6 in that at least part of the N2 gas flow from the cracking reactor 300 is not directed to the gas turbine 100, but is collected and used for different purposes, and the injection points of the gas turbine feed line 1 and the NH3 gas feed line 2 are exchanged. In particular, according to this embodiment, the gas turbine feed line 1 is directed to the gas turbine secondary stage of the gas turbine 100 and the NH3 gas feed line 2 is directed to the gas turbine secondary stage of the gas turbine 100. directed to the primary stage of the gas turbine of the gas turbine 100. Furthermore, the outlet line 8 of the N2 gas flow is connected downstream to a N2 gas pick-up line 3?. The control method for this embodiment is the same as described with reference to Figure 5.

Finally, continuing to refer to Figures 17, Figure 8 illustrates a sixth embodiment of a power generation system using a gas turbine and comprising an ammonia cracking device. The same reference numbers indicate equal or corresponding parts, elements or components already illustrated in Figures 1-7 and described above, and which will not be described again.

The embodiment shown in Figure 8 differs from the embodiments of Figures 3-7 in that at least part of the N2 gas flow from the cracking reactor 300 is not directed to the gas turbine 100, but is directed to the NH3 gas feed line 2. In particular, according to this embodiment, at least part of the N2 gas flow from the cracking reactor 300 is used to purge the NH3 gas feed flow line 2, when necessary.

While aspects of the invention have been described in terms of various specific embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes and omissions are possible without departing from the spirit and scope of the claims. Furthermore, unless otherwise specified herein, the order or sequence of any process or method steps may be varied or re-sequenced in accordance with alternative embodiments.

Claims (19)

Gas turbine auxiliary system for NH3 conditioning CLAIMS 1. Power generation system comprising a gas turbine (100) and an auxiliary gas turbine system for conditioning NH3, wherein the auxiliary gas turbine system for NH3 conditioning is configured to process an ammonia input stream and obtain a decomposition gas comprising at least hydrogen and nitrogen, preferably a NH3/H2/N2 gas mixture, the auxiliary gas turbine system for NH3 conditioning including an ammonia cracking reactor (300), the ammonia inlet stream being separated into a cracking reactor feed line (6) and a NH3 bypass line (11), the ammonia cracking reactor (300) being configured to decompose ammonia into a gaseous mixture of hydrogen and nitrogen or hydrogen, nitrogen and residual ammonia, an outlet line (7) of the cracking reactor gas mixture being connected to the gas turbine (100), the NH3 bypass flow line (11) being connected to the gas turbine (100) through a NH3 gas feed flow line (2), the system comprising the gas turbine feed line and a plurality of flow valves (21, 22, 23, 24, 25), which are controlled by an auxiliary control unit. 2. The power generation system of claim 1, wherein the ammonia cracking reactor (300) is configured to separate a stream of nitrogen and a gaseous mixture of hydrogen and nitrogen or residual hydrogen, residual nitrogen and residual ammonia. 3. A power generation system according to claim 2, wherein the nitrogen separated from the gaseous mixture of hydrogen and nitrogen or from the gaseous mixture of hydrogen, nitrogen and residual ammonia is withdrawn from the ammonia cracking reactor (300) via a nitrogen flow line (8), the nitrogen flow line (8) being connected to the feed line (1) of the gas turbine via a nitrogen gas feed line (9) upstream of the gas turbine (100) and/or to the gas turbine (100) via a nitrogen gas feed line (3) and/or to a nitrogen gas withdrawal line 3?. 4. A power generation system according to any preceding claim, further comprising a bypass separation flow line (10) of NH3 gas, which is connected upstream of the NH3 bypass flow line (11) and downstream of the cracking reactor gas mixture outlet line (7), upstream of the gas turbine (100), to form a gas turbine feed line (1). 5. Power generation system according to any of the preceding claims, wherein the NH3 bypass flow is injected via the NH3 gas feed line (2) into the primary or alternatively secondary stage of the gas turbine (100). 6. A power generation system according to any of claims 1-5, further comprising an NH3 heater/vaporizer/pressurizer (200) configured to heat/vaporize/pressurize an inlet stream of at least partially liquid ammonia. 7. A power generation system according to any of claims 1-5, further comprising an NH3 pressurizer configured to pressurize an inlet stream of ammonia gas. 8. A power generation system according to any of the preceding claims, wherein the plurality of flow valves (21, 22, 23, 24, 25) comprises a gas flow valve (21) disposed along the gas turbine feed line (100) and an NH3 gas bypass flow valve (22) disposed along the NH3 gas feed line (2) connected downstream of the NH3 bypass flow line (11). 9. A power generation system according to claims 4 and 8, wherein the plurality of flow valves (21, 22, 23, 24, 25) also comprises a separate bypass flow valve for NH3 gas (23) arranged along the bypass separation flow line (10) of NH3 gas. 10. A power generation system according to claims 2 and 8, wherein the plurality of flow valves (21, 22, 23, 24, 25) also comprises an N2 gas bypass flow slide valve (24) disposed along the N2 gas bypass line (9) and/or a N2 feed flow slide valve (25) of a gas turbine is disposed along the N2 gas feed flow line (3). 11. A power generation system according to any preceding claim, further comprising a heat recovery system configured to recover at least part of the heat of an exhaust gas stream from the gas turbine (100), the heat recovery system comprising a first heat recovery sub-system (13), configured to convey a first portion of the exhaust gas stream to the cracking reactor (300) and/or a second heat recovery sub-system (14), configured to convey a second portion of the exhaust gas stream to the NH3 heater/vaporizer/pressurizer (200). 12. A power generation system according to claim 11, further comprising at least one heat recovery flow valve (26). 13. Power generation system according to claim 12, wherein the at least one heat recovery flow valve (26) is arranged on the first heat recovery sub-base (13) or on the second heat recovery sub-base (14). 14. A method for controlling the operation of the power generation system of the preceding claims 1-13, the method comprising the following steps: - determine the total amount (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) fed to the gas turbine via the gas turbine feed line (1) and the NH3 gas feed flow (m2) via the NH3 gas feed flow line (2) as a function of the gas turbine parameters; - determine (34) the volumetric composition (x1i) of the NH3/H2/N2 gas mixture flow in the gas turbine feed line (1) and the ratio (35) of the NH3 gas mass flow (m2) via the NH3 gas feed flow line (2) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed line (2) as a function of the combustion parameters (32) and the NOx requirements (33); - determine the operation (Y21) of the gas flow valve (21) by controlling the amount of NH3/H2/N2 gas mixture flow flowing into the gas turbine feed line (1) as a function of the total amount (m1 m2) of gas flow (m1) fed to the gas turbine via the gas turbine feed line (1) and the NH3 gas feed flow (m2) fed to the gas turbine via the NH3 gas feed line (2); and - determine the operation (Y22) of the NH3 gas bypass valve (22) as a function of the ratio (35) of the NH3 gas mass flow (m2)+ via the NH3 gas feed line (2) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed line (2). 15. A method for controlling the operation of the power generation system according to claim 14, the method further comprising the following step: - determine the operation (Y26) of the heat recovery flow valve (26) as a function of the volumetric composition (x1i) of the gas. 16. A method for controlling the operation of the power generation system of the preceding claims 3-13, the method comprising the following steps: - determine the total amount (m1 m2 m3) of gas fed to the gas turbine (100) from the NH3/H2/N2 mixture flow (m1) via the gas turbine feed line (1), the NH3 gas feed flow (m2) via the NH3 gas feed flow line (2) and the N2 gas feed flow (m3) via the N2 gas feed flow line (3) as a function of the gas turbine parameters; - determine (34) the volumetric composition (x1i) of the flow of the NH3/H2/N2 gas mixture in the feed line (1) of the gas turbine, the ratio (35) of the mass flow of NH3 gas (m2) via the NH3 gas feed flow line (2) and the total mass flow (m1 m2) of the flow of the NH3/H2/N2 gas mixture (m1) via the feed line (1) of the gas turbine and the feed flow of NH3 gas (m2) via the NH3 gas feed flow line (2) and the ratio (36) of the mass flow of N2 gas (m3) via the N2 gas feed flow line (3) and the total mass flow (m1 m2) of the flow of the NH3/H2/N2 gas mixture (m1) via the feed line (1) of the gas turbine and the feed flow of NH3 gas (m2) via the feed line (2) NH3 gas supply depending on combustion parameters and NOx requirements; - determine the operation (Y21) of the gas flow valve (21) by controlling the amount of NH3/H2/N2 gas mixture flow flowing into the gas turbine feed line (1) as a function of the total amount (m1 m2 m3) of gas flow fed to the gas turbine by the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1), the NH3 gas feed flow (m2) being fed to the gas turbine via the NH3 gas feed line (2) and the N2 gas feed flow (m3) via the N2 gas feed flow line (3); - determine the operation (Y22) of the NH3 gas bypass flow valve (22) as a function of the ratio (35) of the NH3 gas mass flow (m2) via the NH3 gas feed line (2) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed flow line (2); - determine the operation (Y24) of the N2 gas bypass flow valve (24) as a function of the volumetric composition x1i of the NH3/H2/N2 gas mixture flow in the gas turbine feed line (1); - determine the operation (Y25) of the gas turbine N2 feed flow valve (25) as a function of the ratio (36) of the N2 gas mass flow (m3) via the N2 gas feed flow line (3) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed flow line (2). 17. A method for controlling the operation of the power generation system according to claim 16, the method further comprising the following step: - determine the operation (Y26) of the heat recovery flow valve (26) as a function of the volumetric composition of the gas. 18. A method for controlling the operation of the power generation system of the preceding claims 4-13, the method comprising the following steps: - determine the total amount (m1 m2 m3) of gas fed to the gas turbine (100) from the NH3/H2/N2 mixture flow (m1) via the gas turbine feed line (1), the NH3 gas feed flow (m2) via the NH3 gas feed flow line (2) and the N2 gas feed flow (m3) via the N2 gas feed flow line (3) as a function of the gas turbine parameters; - determine the volumetric composition (34) of the flow of the NH3/H2/N2 gas mixture in the feed line (1) of the gas turbine, the ratio (35) of the mass flow of the NH3 gas (m2) via the NH3 gas feed flow line (2) and the total mass flow (m1 m2) of the flow of the NH3/H2/N2 gas mixture (m1) via the feed line (1) of the gas turbine and the feed flow of the NH3 gas (m2) via the NH3 gas feed line (2) and the ratio (36) of the mass flow of the N2 gas (m3) via the N2 gas feed flow line (3) and the total mass flow (m1 m2) of the flow of the NH3/H2/N2 gas mixture (m1) via the feed line (1) of the gas turbine and the feed flow of the NH3 gas (m2) via the feed flow line (2) of the NH3 gas as a function of combustion parameters and NOx requirements; - determine the operation (Y21) of the gas flow valve (21) by controlling the amount of NH3/H2/N2 gas mixture flow flowing into the gas turbine feed line (1) as a function of the total amount (m1 m2 m3) of gas flow fed to the gas turbine from the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1), the NH3 gas feed flow (m2) fed to the gas turbine via the NH3 gas feed line (2) and the N2 gas feed flow (m3) via the N2 gas feed flow line (3); - determine the operation (Y22) of the NH3 gas bypass flow valve (22) as a function of the ratio (35) of the NH3 gas mass flow (m2) via the NH3 gas feed flow line (2) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed flow line (2); - determine the operation (Y23) of the NH3 gas bypass separation flow valve (23) as a function of the volumetric composition x1i of the NH3/H2/N2 gas mixture flow in the gas turbine feed line (1); - determine the operation (Y24) of the N2 gas bypass flow valve (24) as a function of the volumetric composition x1i of the NH3/H2/N2 gas mixture flow in the gas turbine feed line (1); - determine the operation (Y25) of the N2 feed valve of the gas turbine (25) as a function of the ratio (36) of the mass flow of N2 gas (m3) via the N2 gas feed flow line (3) and the total mass flow (m1 m2) of the NH3/H2/N2 gas mixture flow (m1) via the gas turbine feed line (1) and the NH3 gas feed flow (m2) to the gas turbine via the NH3 gas feed line (2). 19. A method for controlling the operation of the power generation system according to claim 18, the method further comprising the following step: - determine the operation (Y26) of the heat recovery flow valve (26) as a function of the volumetric composition of the gas.