A gas turbine auxiliary system for nh3 conditioning

Abstract

A power generating system comprising a gas turbine (100), a fuel cell (500), and a gas turbine auxiliary system for NH3 conditioning, wherein the gas turbine auxiliary 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 gas NH3 / H2 / N2 mixture, the gas turbine auxiliary system for NH3 conditioning comprising an ammonia cracking reactor (300), the ammonia cracking reactor (300) being configured to de-compose ammonia into a gas mixture of hydrogen, nitrogen and residual ammonia, a separator coupled to said gas turbine (100) and being configured to separate a gas mixture of hydrogen, nitrogen and residual ammonia, into separate streams of hydrogen, nitrogen, ammonia, said separator comprising at least one of: a first separator outlet line (71, 74) connected to said fuel cell (500) for conveying said stream of ammonia to said fuel cell (500), and a second separator outlet line (72, 72b) connected to said fuel cell (500) for conveying said stream of hydrogen to said fuel cell (500).

Description

A gas turbine auxiliary system for NH conditioningDescriptionTECHNICAL FIELD

[0001] The present disclosure concerns a power generating system comprising a gas turbine, a fuel cell, and a gas turbine auxiliary system for NH3 conditioning.BACKGROUND ART

[0002] Gas turbines are commonly used to generate power at power stations by combusting fuel therein. In particular, the basic operation of a gas turbine is a Brayton cycle with air as the working fluid: atmospheric air flows through a compressor that 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 a shaft work output in the process, used to drive the compressor; the unused energy comes out in - the exhaust gases that can be repurposed for external work, such as directly producing thrust in a turboj et engine, or rotating a second, independent turbine (known as a power turbine) that can be connected to a fan, propeller, or electrical generator. The purpose of the gas turbine determines the design so that the most desirable split of energy between the thrust and the shaft work is achieved. The fourth step of the Brayton cycle (cooling of the working fluid) is omitted, as gas turbines are open systems that do not reuse the same air.

[0003] Commonly used fuels include natural gas, propane, diesel, biogas and biodiesel. One of the main problems associated with combusting fuels such as these in gas turbines is the resultant production of carbon dioxide (CO2) gas. Increased CO2 levels in the atmosphere are detrimental 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 which do not generate CO2 upon combustion, or from which CO2 must be removed prior to combustion.

[0004] Carbon-free fuels include ammonia and hydrogen. However, both ammonia and hydrogen have some problems associated with their direct use as fuel in a gas turbine. The main problem associated with the direct use of ammonia as fuel in gasturbines is that during the combustion process ammonia is oxidized to nitrogen oxides NOX, a polluting agent contributing to acid rain and global warming. Additionally, due to the low heat content and low reactivity of ammonia with oxygen, the ammonia combustion within the gas turbine presents stability issues (blow-out) over the entire range of the gas turbine operating conditions. On the other hand, even if the combustion of hydrogen still produces NOXpolluting agents, stability issues (blowout) disappear. Nevertheless, a number of problems isassociated with the use of hydrogen as fuel, including storage problems and the fact that hydrogen is an extremely flammable gas. The availability of N2 as inert within the combustion process could help to reduce NOXemissions depending on the type of flame realized in the gas turbine combustor.

[0005] CN107288780A discloses a system for generating power using a gas turbine, wherein ammonia is used as fuel. Upstream the combustion chamber, ammonia is partly decomposed to generate hydrogen within 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 combusted in the combustion chamber first to release heat to ignite ammonia in the combustion chamber. As a consequence, hydrogen can accelerate the combustion process and, accordingly, the combustion performance of ammonia fuel is improved. In conclusion, the amount of hydrogen supplied is functional to NH3 ignition. However, the system disclosed in CN107288780 does not completely overcome the environmental problems due to the formation of nitrogen oxides due to oxidation of ammonia during the combustion process.

[0006] US11084719B2 discloses a process for generating power using a gas turbine, comprising the steps of: (i) vaporizing and pre-heating liquid ammonia to produce preheated ammonia gas; (ii) introducing the pre-heated ammonia gas into an ammonia- cracking device suitable for converting ammonia gas into a mixture of hydrogen and nitrogen; (iii) converting the pre-heated ammonia gas into a mixture of hydrogen and nitrogen in the device; (iv) cooling the mixture of hydrogen and nitrogen to give a cooled hydrogen and nitrogen mixture; (v) introducing the cooled hydrogen and nitrogen mixture into a gas turbine; and (vi) combusting the cooled hydrogen and nitrogen mixture in the gas turbine to generate power. US11084719B2 also discloses an arrangement where the composition of the mixture of hydrogen and nitrogen exitingthe ammonia cracking device can be adjusted using purification techniques. However, the composition of the output mixture from the cracking process can be far from optimal for the GT operational requirement.

[0007] US11156168B2 discloses a gas turbine plant that is provided with a gas turbine, a heating device, a decomposition gas line, and a decomposition gas compressor. The heating device heats ammonia and thermally decomposes the ammonia to convert the ammonia into decomposition gas including hydrogen gas and nitrogen gas. The decomposition gas line sends the decomposition gas from the heating device to the gas turbine. The decomposition gas compressor increases the pressure of the decomposition gas to a pressure equal to or higher than a feed pressure at which the decomposition gas is allowed to be fed to the gas turbine. US11156168B2 also discloses a control device that adjust the ratio of the flow rate of the decomposition gas to the flow rate of the whole fuel gas (which includes the natural gas and the decomposition gas). The control of such ratio allows obtaining and regulating a mixture of decomposition gas and natural gas to the combustion chamber. However, combusting natural gas still produces a high level of carbon dioxide, which is released to the atmosphere or requires additional carbon capture systems.

[0008] WO2023281265A1 relates to a propulsion system, for thermally integrating an ammonia based cracking reactor into an engine, such an engine may be used in aerospace or other vehicle applications. The propulsion system further comprises a fuel cell module, wherein said ammonia cracking module is thermally balanced with both said engine module and said fuel cell module. Besides the system been suitable just for vehicle or aero-application, the integration between the ammonia cracking module and the fuel cell is made to thermally balance the system, by coupling a heat exchanger downstream a combustion chamber to exchange heat and to power a low pressure turbine. Furthermore, cracked ammonia is delivered firstly to the combustion chamber and the turbine, then to the heat exchanger and only finally to the fuel cell, in a sequential flow.

[0009] In conclusion, the prior art solution approaches either negatively affect the operation costs of the system or have an adverse environmental impact. Accordingly, an improved system generating power using a gas turbine and ammonia as fuel to address the issues of real time conditioning NH3 to realize a gas NH3 / H2 / N2 mixturethat allows operating the gas turbine in every condition would be beneficial and would be welcomed in the technology. NH3 conditioning needs to be pursued flexibly and regulated at different levels along the path towards the turbine, so it is felt the need of a system capable to tune and deliver fuels to the gas turbine at different stages, to improve performances but also abate NOXemission, also by means of NH3 recovery system. More in general, it would be desirable to provide methods and systems adapted to more efficiently address problems entailed by providing an auxiliary system for NH3 conditioning to realize a gas NH3 / H2 / N2 mixture that allows operating the gas turbine in every condition.SUMMARY

[0010] In one aspect, the subject matter disclosed herein is directed to an improved system generating power, such as mechanical and / or electrical power, and wherein the system comprises a gas turbine, a gas turbine auxiliary system for NH3 conditioning, and a fuel cell. Embodiments disclosed herein specifically concern a gas turbine auxiliary system for NH3 conditioning configured to feed a fuel cell with separated streams of ammonia and / or hydrogen whereas the gas turbine is fed with a gas mixture, and preferably with a mixture comprising hydrogen and / or nitrogen.

[0011] Advantageously the power generating system disclosed herein may also include a Selective Catalytic Reduction (SCR) system to reduce NOx emissions and / or be equipped with one or more storage units for storing NH3, H2, heat, electricity, and / or N2 for external uses.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:Fig. l illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a first illustrative nonclaimed example;Fig. 2 illustrates a block diagram of the control architecture of the power generating system of Fig. 1;Fig.3 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a second illustrative nonclaimed example;Fig. 4 illustrates a block diagram of the control architecture of the power generating system of Fig. 3;Fig. 5 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a third illustrative nonclaimed example;Fig. 6 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a fourth illustrative nonclaimed example;Fig. 7 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a fifth illustrative nonclaimed example; andFig. 8 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device according to a sixth illustrative nonclaimed example;Fig. 9 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device and a fuel cell according to a first embodiment;Fig. 10 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device and a fuel cell according to a second embodiment;Fig. 11 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device and a fuel cell according to a third embodiment;Fig. 12 illustrates a schematic of a power generating system using a gas turbine and comprising an ammonia cracking device and a fuel cell according to a fourth embodiment.DETAILED DESCRIPTION OF EMBODIMENTS

[0013] According to one aspect, the present subject matter is directed to a system for generating power using a gas turbine, wherein the system comprises an ammonia- cracking device, to convert at least part of an NH3 stream into H2 and N2, to realize agas NH3 / H2 / N2 mixture that allows operating the gas turbine in every condition.

[0014] In another aspect, the subject matter disclosed herein concerns a gas turbine auxiliary system for NH3 conditioning wherein a NH3 feed stream is splitted into two separate NH3 stream, a first NH3 stream is cracked 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 the cracking reactor, the H2 and N2 stream can be mixed together with the second NH3 stream, to obtain a gas NH3 / H2 / N2 mixture with a controlled ratio of NH3 on one hand and H2 and N2 on the other hand. Optionally, downstream the cracking reactor, N2 can be separated from H2 gas in the H2 and N2 stream, to obtain a gas NH3 / H2 / N2 mixture with a controlled ratio of NH3, H2 and N2 and to additionally allow N2 to be used as a purge gas.

[0015] Reference now will 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 limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase “in one embodiment” or “in an embodiment” or “in some embodiments” in various places throughout the specification is not necessarily referring to the same embodiment s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0016] When introducing elements of various embodiments the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0017] Referring now to the drawings, Fig.1 shows a schematic of an exemplary power generating system comprising a gas turbine 100. The gas turbine 100 comprisesa compressor, a combustion chamber and an expander. The gas turbine 100 is fed by a gas NH3 / H2 / N2 mixture stream and a gas NH3 stream. The gas NH3 / H2 / N2 mixture stream is directed to the primary stage of the gas turbine 100 through a gas turbine feed line 1 and the gas NH3 stream is directed to the secondary stage of the gas turbine 100 through a gas NH3 feed stream line 2. Moreover, a gas turbine auxiliary system for NH3 conditioning is arranged upstream the gas turbine 100, the gas turbine auxiliary system including a NH3 heater / vaporizer / pressurizer 200, to heat and then vaporize a liquid NH3 stream from a NH3 stream line 4, and a cracking reactor 300, which is connected to the NH3 heater / vaporizer / pressurizer through a NH3 heater / vaporizer / pressurizer gas outlet line 5 and a cracking reactor feed line 6. According to alternative examples, the NH3 heater / vaporizer / pressurizer is composed of shell-and-tube heat exchangers or plate-heat-exchangers. In some examples, a heat transfer fluid of the heater / vaporizer / pressurizer is the gas turbine exhaust gas or another intermediate fluid (like steam or thermal oil). According to an example the heat exchanger is made in two stages, one to heat-up and vaporize liquid ammonia, the other to restore the initial pressure or eventually increase the ammonia gas pressure. In some examples, a storage tank for high pressure ammonia gas is also included into the heater / vaporizer / pressurizer system.

[0018] According to an example shown in fig. 1, the NH3 cracking reactor 300 is a catalytic or thermal reactor, configured to process ammonia and dissociate it into at least its basic components, namely hydrogen and nitrogen, in presence of a catalyst or under temperature control, according to the reaction:

[0019] The mixture of hydrogen and nitrogen and eventually present unreacted ammonia resulting from the cracking reaction is then directed to the gas turbine 100 through a gas NH3 / H2 / N2 mixture stream outlet line 7, connected downstream to the gas turbine feed line 1.

[0020] A NH3 bypass stream is splitted from the gas NH3 stream form the heater / vaporizer / pressurizer through a gas NH3 bypass stream line 11, which is connected upstream to the heater / vaporizer / pressurizer gas outlet line 5 and which is connected downstream to the gas NH3 feed stream line 2 of the gas turbine 100, inparticular to the secondary stage of the gas turbine 100.

[0021] The system allows the gas turbine control loop to control the ratio of NH3 to be combusted together with H2 and N2 from the cracking reactor, according to the gas turbine operative needs.

[0022] Exhaust gas from the gas turbine 100 is routed to an exhaust gas stream line 15, from which a portion of the exhaust gas stream 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. With reference to Fig. 1, the exhaust gas heat recovery line 12 is split into a first heat recovery sub-line 13, which is directed to the cracking reactor 300 and a second heat recovery sub-line 14, which is directed to the NH3 heater / vaporizer / pressurizer 200.

[0023] An emergency system (not shown) is arranged along the gas turbine feed line 1 and include a vent and emergency valves to prevent overpressure.

[0024] The gas turbine auxiliary system for NH3 conditioning of Fig. 1 operates as follows. The system is started by liquid ammonia being heated / vaporized / pressurized inside the NH3 heater / vaporizer / pressurizer 200 and fed in gaseous state to the NH3 cracking reactor 300. Part of gaseous ammonia from the NH3 heater / vaporizer / pressurizer 200 is spilled to the gas NH3 bypass stream line 11 and is routed to the gas turbine 100 through the gas NH3 feed stream line 2. Part of the heat produced by the gas turbine 100 is sent to the NH3 heater / vaporizer / pressurizer 200 and to the NH3 cracking reactor 300. Further liquid ammonia is heated, vaporized and pressurized in the vaporizer / pressurizer 200 and the NH3 cracking reactor 300 starts operations feeding gaseous mixture in the gas NH3 / H2 / N2 mixture stream outlet line 7. A storage drum (not shown) can optionally be arranged along the gas NH3 / H2 / N2 mixture stream outlet line 7. When pressure in the gas NH3 / H2 / N2 mixture stream outlet line 7 reaches a threshold value, start-up sequence of the gas turbine can begin. Gas turbine ignition is obtained using as fuel the streams fed through the gas turbine feed line 1 or the gas NH3 feed stream line 2, receiving a gas NH3 stream from the gas NH3 bypass stream line 11. If energy to start-up the NH3 heater / vaporizer / pressurizer 200 and the NH3 cracking reactor 300 is not available, a start-up fuel like natural-gas can be connected to the gas turbine feed line 1 or the gas NH3 feed stream line 2 andutilized for gas turbine ignition and ramp-up to gas turbine end-of-sequence or full- speed-no-load condition. Once the gas turbine is ignited, the exhaust gas heat starts to provide energy both to the NH3 heater / vaporizer / pressurizer 200 that heats, vaporizes and pressurizes liquid ammonia to gaseous state ammonia and to the NH3 cracking reactor 300 that cracks gaseous ammonia to a mixture of hydrogen, nitrogen and eventual unreacted ammonia. Once appropriate mixture is created, the flow of the gas NH3 / H2 / N2 mixture stream inside the gas turbine feed line 1 is controlled according to the gas turbine control schedules. During all the gas turbine sequences (ramp-up, load operations, normal shutdown) a gas turbine auxiliary control unit 37 manages the requirements of hydrogen, nitrogen and residual ammonia mixture composition of the gas turbine feed line 1, acting on the parameters of the NH3 cracking reactor 300 and managing the flow ratio between the gas turbine feed line 1 and the gas NH3 feed stream line 2. The parameters of the NH3 cracking reactor managed by the gas turbine auxiliary control unit 37 are strictly dependent from the NH3 cracking reactor technology. In some examples, the parameters of the NH3 cracking reactor comprise the temperature of the reacting ammonia gas at specific sections of the reactor (for example at the inlet section) and the NH3 cracking reactor recycle ratio. Emergency shutdown of the gas turbine 100 enables the immediate isolation of the gas turbine auxiliary system for NH3 conditioning from the gas turbine 100 and the deenergization of the NH3 heater / vaporizer / pressurizer 200 and the NH3 cracking reactor 300 according to its specific safety requirements.

[0025] The operation of the gas turbine auxiliary system for NH3 conditioning of Fig. 1 is controlled through a plurality of control valves operated according to a control method that will be explained herein below. A gas flow valve 21 is arranged along the gas turbine feed line 1, to control the flowing of the gas NH3 / H2 / N2 mixture stream inside the gas turbine feed line 1. A gas NH3 bypass stream flow valve 22 is arranged along the gas NH3 feed stream line 2, downstream the gas NH3 bypass stream line 11, to control the flow of gas NH3 bypass stream directed to the gas turbine 100, and conversely the flow of gas NH3 stream directed to the cracking reactor 300 through the cracking reactor feed line 6. Finally, a heat recovery flow valve 26 is arranged on the first heat recovery sub-line 13 in order to control the portion of the exhaust gas from the gas turbine 100 that is directed to the NH3 cracking reactor 300 and conversely the portion of exhaust gas directed to the NH3 heater / vaporizer / pressurizer 200. The gasflow valve 21, the gas NH3 bypass stream flow valve 22 and the heat recovery flow valve 26 can be electric-actuated valves, pneumatic-actuated valves or hydraulic- actuated valves.

[0026] With continuing reference to fig. 1, according to the block diagram of the control architecture of the power generating system shown in fig. 2, the flow valves 21 and 22 and the heat recovery flow valve 26 are operated as follows. A gas turbine control unit 30 such as, for example, a computer or 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 examples, the gas turbine parameters 31 comprise the gas turbine generated power, the gas turbine speed, the gas turbine exhaust gas temperature. The combustion parameters 32 are dependent on the combustion technology adopted by the gas turbine. In some examples, the combustion parameters 32 comprise fuel-to-air-ratio in specific zones of the combustor, distribution of the thermal load along the combustor and the NOXand NH3 slip at the outlet of the combustor. NOXrequirements 33 comprise NOXexhaust gas emissions in the exhaust stream downstream the gas turbine. The total amount of gas fed to the gas turbine through the gas turbine feed line 1 (indicated with ml) and the gas NH3 feed stream line 2 (m2) are a function of the above gas turbine parameters: ml + m2 = f(GT param)The volumetric composition of the gas NH3 / H2 / N2 mixture stream in the gas turbine feed line 1 (indicated by the reference number 34 in Fig. 2); the ratio 35 of the gas NH3 mass flow through the gas NH3 feed stream line 2 (m2) and the total mass flow (ml+m2) of the gas NH3 / H2 / N2 mixture stream through the gas turbine feed line 1 (ml) and the gas NH3 feed stream to the gas turbine through the gas NH3 feed stream line 2 (m2) are a function of the above combustion parameters and NOXrequirements: xii = f(combustion parameters; NOXrequirements) m2 / (ml + m2) = f(combustion parameters; NOXrequirements)These parameters are the input(s) to the auxiliary control unit 37 such as, for example, 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 relations. The operation Y21 of the gas flow valve 21 controlling the amount of gas NH3 / H2 / N2 mixture stream flowing inside the gas turbine feed line 1, isa function of the total amount of gas stream ml fed to the gas turbine through the gas turbine feed line 1 and the gas NH3 feed stream m2 fed to the gas turbine through the gas NH3 feed line 2:Y21 = f(ml + m2)The operation Y22 of the gas NH3 bypass stream valve 22 is a function of the ratio 35 of the gas NH3 mass flow m2 through the gas NH3 feed stream line 2 and the total mass flow of the gas NH3 / H2 / N2 mixture stream ml through the gas turbine feed line 1 and the gas NH3 feed stream m2 to the gas turbine through the gas NH3 feed stream line 2:Y22 = f(m2 / (ml + m2))Finally, the operation of the heat recovery flow valve 26 is a function of the volumetric composition of the gas:Y26 = f(xii)

[0027] The above described control method allows to change the composition of the fuel to the gas turbine and inject ammonia in any ratio according to any eventual combustor and gas turbine requirements (these requirements not being part of the present disclosure).

[0028] With continuing reference to Fig. 1 and Fig. 2, Fig.3 shows a schematic of an exemplary power generating system according to a second example. The gas turbine 100 comprises a compressor, a combustion chamber and a turbine. The gas turbine 100 is fed by a gas NH3 / H2 / N2 mixture stream, a gas NH3 stream and a gas N2 stream. The gas NH3 / H2 / N2 mixture stream is directed to the primary stage of the gas turbine of the gas turbine 100 through a gas turbine feed line 1, the gas NH3 stream is directed to the secondary stage of the gas turbine of the gas turbine 100 through a gas NH3 feed stream line 2 and the gas N2 stream is directed to the secondary stage of the gas turbine of the gas turbine 100 through a gas N2 feed stream line 3. Moreover, a gas turbine auxiliary system for NH3 conditioning is arranged upstream the gas turbine 100, the gas turbine auxiliary system including a NH3 heater / vaporizer / pressurizer 200, to heat and then vaporize a liquid NH3 stream from a NH3 stream line 4, and a cracking reactor 300, which is connected to the NH3 heater / vaporizer / pressurizer through a NH3 heater / vaporizer / pressurizer gas outlet line 5 and a cracking reactor feed line 6.

[0029] According to this example, the mixture of hydrogen and nitrogen andunreacted ammonia resulting from the cracking reaction is treated to separate a gas NH3 / H2 / N2 mixture stream and a gas N2 stream. The gas NH3 / H2 / N2 mixture stream from the cracking reactor 300 is directed to the gas turbine 100 through a gas NH3 / H2 / N2 mixture stream outlet line 7, connected downstream to the gas turbine feed line 1.

[0030] The separation of nitrogen can be obtained through different technologies. According to an example, the NH3 cracking reactor 300 is a membrane reactor, operating as follows. A membrane separates the reactor into two separate sections. A first section is directly connected to the cracking reactor feed line 6. Ammonia fed to the membrane reactor is reacted inside the first section. 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 remain inside the first section of the membrane reactor.

[0031] The gas N2 stream from the cracking reactor 300 is directed to the gas turbine 100 through a gas N2 stream outlet line 8, connected downstream to the gas N2 feed stream line 3. A fraction of the gas N2 stream from the cracking reactor 300 can be split and returned to the gas NH3 / H2 / N2 mixture stream outlet line 7 through a gas N2 bypass line 9, to control the composition of the NH3 / H2 / N2 mixture stream directed to the gas turbine 100 through the gas turbine feed line 1.

[0032] A NH3 bypass stream is splitted (split off) from the gas NH3 stream form the heater / vaporizer / pressurizer through a gas NH3 bypass stream line 11, which is connected upstream to the heater / vaporizer / pressurizer gas outlet line 5 and which is connected downstream to the gas NH3 feed stream line 2 of the gas turbine 100, in particular to the secondary stage of the gas turbine of the gas turbine 100.

[0033] The composition of the NH3 / H2 / N2 mixture stream directed to the gas turbine 100 through the gas turbine feed line 1 is also controlled by mixing the gas NH3 / H2 / N2 mixture stream with ammonia. To this end a gas NH3 bypass split stream is withdrawn from the gas NH3 bypass stream through a gas NH3 bypass split stream line 10, which is connected upstream to the gas NH3 bypass stream line 11 and downstream to the gas NH3 / H2 / N2 mixture stream outlet line 7.

[0034] The system allows the gas turbine control loop to control the ratio of NH3 tobe combusted together with H2 and N2 from the cracking reactor, according to the gas turbine operative needs.

[0035] Exhaust gas from the gas turbine 100 is routed to an exhaust gas stream line 15, from which a portion of the exhaust gas stream 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. With reference to Fig. 3, the exhaust gas heat recovery line 12 is split into a first heat recovery sub-line 13, which is directed to the cracking reactor 300 and a second heat recovery sub-line 14, which is directed to the NH3 heater / vaporizer / pressurizer 200.

[0036] An emergency system (not shown) is arranged along the gas turbine feed line 1 and include a vent and emergency valves to prevent overpressure.

[0037] The gas turbine auxiliary system for NH3 conditioning of Fig. 3 operates as follows. The system is started by liquid ammonia being heated / vaporized / pressurized inside the NH3 heater / vaporizer / pressurizer 200 and fed in gaseous state to the NH3 cracking reactor 300. Part of gaseous ammonia from the NH3 heater / vaporizer / pressurizer 200 is spilled to the gas NH3 bypass stream line 11 and is routed to the gas turbine 100 through the gas NH3 feed stream line 2. Part of the heat produced by the gas turbine 100 is sent to the NH3 heater / vaporizer / pressurizer 200 and to the NH3 cracking reactor 300. Further liquid ammonia is heated, vaporized and pressurized in the vaporizer / pressurizer 200 and the NH3 cracking reactor 300 starts operations feeding gaseous mixture in the gas NH3 / H2 / N2 mixture stream outlet line 7. A storage drum (not shown) can optionally be arranged along the gas NH3 / H2 / N2 mixture stream outlet line 7. When pressure in the gas NH3 / H2 / N2 mixture stream outlet line 7 reaches a threshold value, start-up sequence of the gas turbine can begin. Gas turbine ignition is obtained using as fuel the streams fed through the gas turbine feed line 1 or the gas NH3 feed stream line 2, receiving a gas NH3 stream from the gas NH3 bypass stream line 11. If energy to start-up the NH3 heater / vaporizer / pressurizer 200 and the NH3 cracking reactor 300 is not available, a start-up fuel like natural-gas can be connected to the gas turbine feed line 1 or the gas NH3 feed stream line 2 and utilized for gas turbine ignition and ramp-up to gas turbine end-of-sequence or full- speed-no-load condition. Once the gas turbine is ignited, the exhaust gas heat starts to provide energy both to the NH3 heater / vaporizer / pressurizer 200 that heats, vaporizesand pressurizes liquid ammonia to gaseous state ammonia and to the NH3 cracking reactor 300 that cracks gaseous ammonia to a mixture of hydrogen, nitrogen and unreacted ammonia. Once appropriate mixture is created, the flow of the gas NH3 / H2 / N2 mixture stream inside the gas turbine feed line 1 is controlled according to the gas turbine control schedules. During all the gas turbine sequences (ramp-up, load operations, normal shutdown) a gas turbine control system manages the requirements of hydrogen, nitrogen and residual ammonia mixture composition of the gas turbine feed line 1, acting on the parameters of the NH3 cracking reactor 300 and managing the flow ratio between the gas turbine feed line 1 and the gas NH3 feed stream line 2. Emergency shutdown of the gas turbine enables the immediate isolation of the gas turbine auxiliary system for NH3 conditioning from the gas turbine and the deenergization of the NH3 heater / vaporizer / pressurizer 200 and the NH3 cracking reactor 300 according to its specific safety requirements. The NH3 cracking reactor 300 also separates nitrogen from the gas mixture of hydrogen, nitrogen and unreacted ammonia and therefore provides a stream of N2 in the gas N2 stream outlet line 8, which can be used for different applications, like N2 storage or purging services for the gas turbine.

[0038] The operation of the gas turbine auxiliary system for NH3 conditioning of Fig. 3 is controlled through a plurality of control valves operated according to a control method that will be explained herein below. A gas flow valve 21, namely a valve 21, is arranged along the gas turbine feed line 1, to control the flowing of the gas NH3 / H2 / N2 mixture stream inside the gas turbine feed line 1. A gas NH3 bypass stream flow valve 22 is arranged along the gas NH3 bypass stream line 11 to control the flow of gas NH3 bypass stream directed to the gas turbine through the gas NH3 feed stream line 2, and conversely the flow of gas NH3 stream directed to the cracking reactor 300 through the cracking reactor feed line 6. A gas NH3 bypass split stream flow valve 23 is arranged along the gas NH3 bypass split stream line 10 to control the amount of gas NH3 bypass stream routed to the gas NH3 / H2 / N2 mixture stream outlet line 7 in order to control the composition of the NH3 / H2 / N2 mixture stream directed to the gas turbine 100 through the gas turbine feed line 1. A gas N2 bypass stream flow valve 24 is arranged along the gas N2 bypass line 9 to control the flow of nitrogen of the gas N2 stream outlet line 8 from the NH3 cracking reactor 300 used to mix with the gas NH3 / H2 / N2 mixture stream directed to the gas turbine 100 through the gas turbine feed line 1. Additionally a gas turbine N2 feed stream flow valve 25 is arranged along thegas N2 feed stream line 3, to control the flow of nitrogen of the gas N2 stream outlet line 8 from the NH3 cracking reactor 300 directed to the gas turbine 100. Finally, a heat recovery flow valve 26 is arranged on the first heat recovery sub-line 13 in order to control the portion of the heat recovery flow of the exhaust gas from the gas turbine 100 that is directed to the NH3 cracking reactor 300 and conversely the portion of heat recovery flow directed to the NH3 heater / vaporizer / pressurizer 200. The gas flow valve 21, the gas NH3 bypass stream flow valve 22, the gas NH3 bypass split stream flow valve 23, the gas N2 bypass stream flow valve 24, the gas turbine N2 feed stream flow valve 25 and the heat recovery flow valve 26 can be electric-actuated valves, pneumatic-actuated valves or hydraulic-actuated valves.

[0039] With continuing reference to Fig. 3, according to the block diagram of the control architecture of the power generating system shown in Fig. 4, the flow valves 21-25 and the heat recovery flow valve 26 are operated as follows. 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 gas NH3 / H2 / N2 mixture stream (ml) through the gas turbine feed line 1, the gas NH3 feed stream line 2 and the gas N2 feed stream (m3) through the gas N2 feed stream line 3 is a function of the gas turbine parameters: ml + m2 + m3 = f(GT param)The volumetric composition of the gas NH3 / H2 / N2 mixture stream in the gas turbine feed line 1 (indicated by the reference number 34 in Fig. 2); the ratio 35 of the gas NH3 mass flow m2 through the gas NH3 feed stream line 2 and the total mass flow of the gas NH3 / H2 / N2 mixture stream ml through the gas turbine feed line 1 and the gas NH3 feed stream m2 to the gas turbine through the gas NH3 feed stream line 2; and the ratio 36 of the gas N2 mass flow through the gas N2 feed stream line 3 and the total mass flow of the gas NH3 / H2 / N2 mixture stream through the gas turbine feed line 1 and the gas NH3 feed stream to the gas turbine through the gas NH3 feed stream line 2 are a function of the combustion parameters and NOx requirements: xii = f(combustion parameters; NOx requirements) m2 / (ml + m2) = f(combustion parameters; NOx requirements) m3 / (ml + m2) = f(combustion parameters; NOx requirements)These parameters are the input of an auxiliary control unit 37, controlling the operation of the flow valves 21-25 and the heat recovery flow valve 26 according to the followingrelations. The operation Y21 of the gas flow valve 21 controlling the amount of gas NH3 / H2 / N2 mixture stream flowing inside the gas turbine feed line 1, is a function of the total amount of gas fed to the gas turbine through the gas turbine feed line 1 (ml), the gas NH3 feed stream line 2 (m2) and the gas N2 feed stream line 3 (m3):Y21 = f(ml + m2 + m3)The operation Y22 of the gas NH3 bypass stream valve 22 is a function of the ratio 35 of the gas NH3 mass flow through the gas NH3 feed stream line 2 and the total mass flow of the gas NH3 / H2 / N2 mixture stream through the gas turbine feed line 1 and the gas NH3 feed stream to the gas turbine through the gas NH3 feed stream line 2:Y22 = f(m2 / (ml + m2))The operation Y23 of the gas NH3 bypass split stream valve 23 is a function of the volumetric composition of the gas NH3 / H2 / N2 mixture stream in the gas turbine feed line 1 :Y23 = f(xii)Also the operation Y24 of the gas N2 bypass stream valve 24 is a function of the volumetric composition of the gas NH3 / H2 / N2 mixture stream in the gas turbine feed line 1 :Y24 = f(xii)The operation Y25 of the gas turbine N2 feed stream valve 25 is a function of the ratio 36 of the gas N2 mass flow m3 through the gas N2 feed stream line 3 and the total mass flow of the gas NH3 / H2 / N2 mixture stream through the gas turbine feed line 1 and the gas NH3 feed stream to the gas turbine through the gas NH3 feed stream line 2:Y25 = f(m3 / (ml + m2))Finally, the operation of the heat recovery flow valve 26 is a function of the volumetric composition of the gas NH3 / H2 / N2 mixture stream in the gas turbine feed line 1 :Y26 = f(xii)

[0040] The above described control method allows to change the composition of the fuel to the gas turbine and inject ammonia and nitrogen in any ratio according to any eventual combustor and gas turbine requirements (these requirements not being part of the present disclosure).

[0041] For example: if the combustor requires an hydrogen-rich fuel but a consistent inert fluid (N2) to reduce flame temperatures and augment power of the gas turbine, then Case 1 of the following Table 1 is applicable. If the combustor requires ahydrogen-rich fuel but a consistent separate ammonia injection, to optimize NOx emission, Case 3 of Table 1 is applicable. In case the combustor does not require high amount of hydrogen, high separate ammonia and high separate nitrogen, Case 2 ofTable 1 is applicable.Table 1

[0042] With continuing reference to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, Fig. 5 illustrates a third example of a power generating system using a gas turbine and comprising an ammonia cracking device. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Fig. 1, Fig. 2, Fig. 3 and Fig. 4 and described above, and which will not be described again.

[0043] The example shown in Fig. 5 differs from the example of Fig. 3 in that at least part of the gas N2 stream from the cracking reactor 300 is not directed to the gas turbine 100, but is collected and used for different purposes. According to this example, the gas N2 stream outlet line 8 is connected downstream to a gas N2 withdrawal line 3’. A stream valve 25’ is arranged along the gas N2 withdrawal line 3’, to control the flow of nitrogen of the gas N2 stream outlet line 8 from the NH3 cracking reactor 300 directed to external uses. The control method for this example differs from that described with reference to Fig. 3 and Fig. 4 in that the operation Y25 of the stream valve 25’ is a function of requirements that do not form an object of the present invention:Y25’ = f(other requirements)

[0044] With continuing reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5, Fig. 6 illustrates a fourth example of a power generating system using a gas turbine and comprising an ammonia cracking device. The same reference numbers designate thesame or corresponding parts, elements or components already illustrated in Fig. 1, Fig. 2, Fig. 3, Fig. 4 and Fig. 5 and described above, and which will not be described again.

[0045] The example shown in Fig. 6 differs from the examples of Fig. 3 and Fig. 5 in that the injection points of the gas turbine feed line 1 and the gas NH3 feed stream line 2 are swapped. Swapping the injection points can be needed to take into account different combustion technologies that could be applied into the gas turbine with different flame evolution along the flow path inside the combustor. In particular, according to this example, the gas turbine feed line 1 is directed to the secondary stage of the gas turbine of the gas turbine 100 and the gas NH3 feed stream line 2 is directed to the primary stage of the gas turbine of the gas turbine 100. The control method for this example is the same as that described with reference to Fig. 3 and Fig. 4.

[0046] Moreover, with continuing reference to Figs. 1-6, Fig. 7 illustrates a fifth example of a power generating system using a gas turbine and comprising an ammonia cracking device. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Figs. 1-6 and described above, and which will not be described again.

[0047] The example shown in Fig. 7 differs from the examples of Figs. 3-6 in that both at least part of the gas N2 stream 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 gas NH3 feed stream line 2 are swapped. In particular, according to this example, the gas turbine feed line 1 is directed to the secondary stage of the gas turbine of the gas turbine 100 and the gas NH3 feed stream line 2 is directed to the primary stage of the gas turbine of the gas turbine 100. Moreover, the gas N2 stream outlet line 8 is connected downstream to a gas N2 withdrawal line 3’. The control method for this example is the same as that described with reference to Fig. 5.

[0048] With continuing reference to Figs. 1-7, Fig. 8 illustrates a sixth example of a power generating system using a gas turbine and comprising an ammonia cracking device. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Figs. 1-7 and described above, and which will not be described again.

[0049] The example shown in Fig. 8 differs from the examples of Figs. 3-7 in that at least part of the gas N2 stream from the cracking reactor 300 is not directed to the gas turbine 100, but is routed to the gas NH3 feed stream line 2. In particular, according to this example, at least part of the gas N2 stream from the cracking reactor 300 is used to purge the gas NH3 feed stream line 2, when needed.

[0050] With continuing reference to Figs. 1-8, Figs. 9-12 illustrates some embodiments of a system comprising a gas turbine 100, a gas turbine auxiliary system for NH3 conditioning, and a fuel cell 500. These embodiments differ from the illustrative non-claimed examples of Figs. 1-8 at least in that they further comprise a fuel cell 500. Moreover, although the embodiments illustrated in Figs. 1-8 have been described as comprising a NH3 bypass line being connected to the gas turbine 100 through a gas NH3 feed stream line that directs the NH3 stream to the bypass line, it will be apparent to those of ordinary skill in the art that the power generating systems illustrated in Figs. 9-12 do not necessarily require the NH3 bypass line, therefore the power generating systems illustrated in Fig. 9-12 may or may not comprise the NH3 bypass line. Fig. 9 in particular, illustrates a first embodiment of a power generating system, which does not comprise a NH3 bypass line. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Figs. 1-8 and described above.

[0051] Although not shown in Figs. 9-12, it will be apparent to those of ordinary skill in the art that the power generating systems described hereinbelow may comprise a plurality of gas turbines 100 and / or a plurality of fuel cells 500. Each of the one or more gas turbines 100 can operate in power generation mode or as a mechanical drive. The plurality of fuel cells 500 can be of the same type or different type.

[0052] In Fig. 9, the fuel cell 500 is arranged downstream the gas turbine 100 and is fed using the separate streams of ammonia and / or hydrogen to generate electrical power and / or heat to power / heat auxiliaries or for other purposes. In this embodiment, the system allows to decompose ammonia at high temperature and operate the fuel cell 500 at high temperature, such as a temperature equal or higher than 100 °C, preferably above 200 °C.

[0053] The system generates power, such as mechanical power by means of the gasturbine 100 and / or electrical power by means of at least one of the gas turbines 100 and the fuel cell 500. In this way, when the gas turbine 100 operates in power generation mode or as a mechanical drive, such as for oil & gas applications or industrial applications, the combined usage of the gas turbine 100 and the fuel cell 500 allows to exploit performances of both technologies providing a versatile approach which can suit different scenarios. For example, in liquefied natural gas (LNG) and natural gas (NG) plants the gas turbine(s) 100 can be used for mixed refrigerant (MR) or propane refrigerant (PR) while the fuel cell(s) 500 can be used to power the plant auxiliaries equipped with a storage.

[0054] The gas turbine auxiliary system for NH3 conditioning is arranged upstream the gas turbine 100 and is configured to process an ammonia input stream and obtain a decomposition gas comprising at least hydrogen and nitrogen, preferably a gas NH3, H2, N2 mixture.

[0055] The gas turbine 100 is coupled to the separator and is fed with a gas mixture, and preferably with a mixture comprising hydrogen and / or nitrogen. The turbine, in turn, generates power and heat. The latter can be conveyed to a heat recovery steam generator (HRSG) 110 with a post-firing module to provide sufficient heat to decompose ammonia at high temperature and / or to heat a reactant stream, such as a stream of N2 / NH3 / H2, preferably a stream of H2 or NH3, used within the system.

[0056] As described with reference to Figs. 1-8, in Fig. 9 the gas turbine auxiliary system comprises an ammonia cracking reactor 300 that is configured to decompose ammonia into a gas mixture of hydrogen, nitrogen and unreacted, or residual, ammonia to be sent to the heat exchanger 710 and after to the separating module 720. The ammonia cracking reactor 300 can be, for example, a catalytic, a thermal reactor or a membrane reactor.

[0057] The system further comprises a separator configured to separate the gas mixture of hydrogen, nitrogen and unreacted, or residual, ammonia, into separate streams of hydrogen, nitrogen, and ammonia.

[0058] The separator may be provided downstream of the cracking reactor 300 and comprises at least one of a heat exchanger 710; a separating module 720; and a membrane that may be part of the membrane reactor itself or be external to it.

[0059] The heat exchanger 710 may be fed by a gas mixture outlet line of the cracking reactor 300 and may, in turn, provide the cooled gas mixture to the separating module 720 through a connecting line 75.

[0060] The separating module 720 can be a Pressure Swing Adsorption (PSA) separator that separates the gas species of the gas mixture using pressure according to the species' molecular characteristics and affinity for an adsorbent material provided therewithin. The separating module 720 allows to recover unreacted, or residual, ammonia thus maximizing the overall system efficiency. The separating module 720 can be connected downstream of the heat exchanger 710.

[0061] The heat exchanger 710 is configured to pre-heat the stream of ammonia and / or the stream of hydrogen that enters the fuel cell 500 at a preset temperature at least sufficient for operating the fuel cell 500, In this manner, the heat exchanger provides sufficient heat to operate the fuel cell 500 at high temperature, for example a temperature of at least 600°C, preferably between 600°C and 700°C.when the fuel cell 500 is fed with pre-heated ammonia and / or pre-heated hydrogen by the heat exchanger 710. However, as it will be apparent to those of ordinary skill, any gas leakage within the power generation system, such as H2, N2, NH3, and / or the gas mixture can be conveyed to the fuel cell 500, after being heated if needed by the fuel cell 500 requirements.

[0062] For example, in Fig. 9 the separating module 720 provides separated streams of hydrogen and ammonia to the heat exchanger 710, which in turn heats the corresponding streams to allow high temperature operation of the fuel cell 500. In Fig. 9 the stream of ammonia is provided from the separating module 720 to the heat exchanger 710 through the connecting line 74.

[0063] The separator comprises one or more outlet lines for conveying the separate streams of hydrogen, nitrogen, ammonia to the respective module of the power generating system, such as the gas turbine 100, the HRSG 110, the fuel cell 500, and / or the cracking reactor 300. For example, the separator comprises a first separator outlet line 71 and a second separator outlet line 72.

[0064] The first separator outlet line 71, which connects the heat exchanger 710 with the fuel cell 500, conveys the stream of ammonia to the fuel cell 500. The stream ofammonia provided by the heat exchanger 710 may be cooled to the required temperature. For example, if the fuel cell 500 requires a temperature of 200°C to operate and heat exchanger 710 outputs a stream of ammonia at a temperature of at least 600°C, a further heat exchanger (not shown in Fig. 9) may cool the stream of ammonia at the required temperature before entering the fuel cell 500 for operating of the same according to the specific fuel cell requirements / technology. The further heat exchanger may be provided on the first separator outlet line 71. The first separator outlet line 71 may also be connected to the cracking reactor 300 and / or the post-firing module through the connecting line 71a, as shown in Fig. 9, for conveying the stream of ammonia thereto.

[0065] The second separator outlet line 72 provides a stream of hydrogen to the fuel cell 500. In this embodiment, the second separator outlet line 72 comprises a first outlet section 72a to convey a stream of hydrogen from the separating module 720 to the heat exchanger 710 and a second outlet section 72b to convey the pre-heated stream of hydrogen from the heat exchanger 710 to the fuel cell 500 at the required temperature to allow operation of the fuel cell 500 according to the specific fuel cell requirements / technology. The second separator outlet line 72 may also be connected to gas turbine 100 and / or post-firing module for conveying at least a portion of the stream of hydrogen to these respective components, as shown in Fig. 9.

[0066] The separator may also comprise a third separator outlet line 73 vented to the air or possibly connected to the gas turbine 100 for conveying the stream of nitrogen to the gas turbine 100, as shown in Fig. 9.

[0067] The gas turbine 100 may comprise a HRSG 110, to recover at least part of the heat of an exhaust gas stream 15 from the gas turbine 100 and direct at least part of the heat to the ammonia cracking reactor 300, in order to provide thermal power thereto.

[0068] In some embodiments, in order to further reduce NOXemission from the gas turbine 100, the HRSG 110 may comprise a Selective Catalytic Reduction (SCR) system which provides for selective catalytic reduction of NOXusing ammonia or urea as the reducing agent, especially when the combustion system of the gas turbine is not dry low NOX(DLN) or dry low emissions (DNE). Accordingly, the proposed system configuration shown in Fig. 9 allows to further reduce the environmental impact of thewhole system.

[0069] The HRSG 110 may comprise a post-firing module configured to receive and process at least a portion of the stream of hydrogen from the separator outlet line 72 and / or a stream of ammonia from the connecting line 71a with the exhaust gas stream 15 to generate additional heat and convey at least part of the additional heat to the ammonia cracking reactor 300, thus allowing to decompose ammonia at high temperature while increasing the efficiency of the overall system.

[0070] The power generating system may also comprise heat exchangers, such as a second heat exchanger (not shown in Fig. 9) configured to preheat an ammonia input stream entering into the ammonia cracking reactor 300 and / or the fuel cell 500 by using the heat generated by the gas turbine auxiliary system and / or the gas turbine 100. Alternatively, the ammonia input stream entering into the ammonia cracking reactor 300 may be provided to the ammonia cracking reactor 300 at the required temperature by an external heating system.

[0071] Alternatively, or in addition, the power generating system may comprise a third heat exchanger 800 to preheat the air entering the fuel cell 500. The third heat exchanger 800 may use at least a part of the power generated by the fuel cell 500 to heat clean air downstream the filter house of the gas turbine 100.

[0072] The remaining part of the heat generated by the fuel cell 500 may be conveyed to the ammonia cracking reactor 300 providing additional heat for decomposing ammonia or may be conveyed outside the system for external uses.

[0073] The power generating system may comprise at least one compression system being configured to adjust a fluid pressure and / or conveying the fluid outside the system for external uses. The fluid may comprise any fluid of the system, such as the gas mixture generated by the gas turbine auxiliary system, the stream of hydrogen, the stream of nitrogen, or the stream of ammonia.

[0074] The power generating system may be equipped with one or more storage units (not shown in Fig. 9) for storing NH3, H2, heat, electricity, and / or N2. For example, the first separator outlet line 71 may comprise an ammonia storage system being arranged along the outlet line 71, the second separator outlet line 72 may comprise a hydrogenstorage system being arranged along the outlet line 72, and the third separator outlet line 73 may comprise a nitrogen storage system being arranged along the outlet line 73.

[0075] With continuing reference to Fig. 9, Fig. 10 illustrates a second embodiment of a power generating system using a gas turbine 100 and comprising an ammonia cracking device 300 and a fuel cell 500. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Fig. 9 and described above, and which will not be described again.

[0076] The embodiment shown in Fig. 10 differs from the embodiment of Fig. 9 at least in that the system does not comprise a HRSG with a firing module. The gas turbine exhaust stream 15 will provide sufficient heat to the ammonia cracking reactor 300 to allow operation of the same. Accordingly, the system shown in Fig. 10 allows to decompose ammonia at low temperature while operating the fuel cell 500 at high temperature.

[0077] With continuing reference to Figs. 9 and 10, Fig. 11 illustrates a third embodiment of a power generating system using a gas turbine 100 and comprising an ammonia cracking device 300 and a fuel cell 500. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Figs. 9 and 10 and described above, and which will not be described again.

[0078] The embodiment shown in Fig. 11 differs from the embodiment of Fig. 9 at least in that does not comprise a first outlet section 72a to convey a stream of hydrogen from the separating module 720 to the heat exchanger 710 and a second outlet section 72b to convey the pre-heated stream of hydrogen from the heat exchanger 710 to the fuel cell 500. The embodiment of Fig. 11 further differs in that the separator outlet line 71 is not connected to the fuel cell 500.

[0079] In contrast with Fig. 9, in Fig. 11 the stream of ammonia from the connecting line 74 and / or the stream of hydrogen from the second separator outlet line 72 is not pre-heated, but fed directly by the separating module 720 to the fuel cell 500. As such, the stream of ammonia and / or hydrogen is provided at a low temperature, such as a temperature less than 100°C, preferably between 60°C and 80°C, to the fuel cell 500. For example, the stream of hydrogen is provided to the fuel cell 500 using the secondseparator outlet line 72, whereas the stream of ammonia is provided using another outlet line 74, which in this case connects the separating module 720 with the fuel cell 500. Additionally, or alternatively, the stream of ammonia can be fed directly to the fuel cell 500 from the ammonia input stream entering into the ammonia cracking reactor 300 and / or the preheater 710 providing sufficient ammonia for the fuel cell 500 needs. The configuration shown in Fig. 11 allows to operate the fuel cell 500 at low temperature, such as a temperature lower than 100 °C, preferably between 60 and 80 °C, while operating the ammonia cracking reactor 300 at high temperature, such as a temperature above 700 °C, preferably between 700°C and 800°C.

[0080] With continuing reference to Figs. 9-11, Fig. 12 illustrates a fourth embodiment of a power generating system using a gas turbine 100 and comprising an ammonia cracking device 300 and a fuel cell 500. The same reference numbers designate the same or corresponding parts, elements or components already illustrated in Figs. 9-11 and described above, and which will not be described again.

[0081] The embodiment shown in Fig. 12 differs from the embodiment of Fig. 9 in that it does not comprise a HRSG with a firing module. In Fig. 12 the gas turbine exhaust stream 15 will provide sufficient heat to the ammonia cracking reactor 300 to perform low temperature decomposition of ammonia, such as a decomposition of ammonia at a temperature between 350°C and 700°C, preferably between 350°C and 550°C.

[0082] Fig. 12 further differs from the embodiment of Fig. 9 in that does not comprise a first outlet section 72a to convey a stream of hydrogen from the separating module 720 to the heat exchanger 710 and a second outlet section 72b to convey the pre-heated stream of hydrogen from the heat exchanger 710 to the fuel cell 500. Furthermore, the separator outlet line 71 is not connected to the fuel cell 500.

[0083] In contrast with Fig. 9, in Fig. 12 the stream of ammonia from the connecting line 74 and / or the stream of hydrogen from the second separator outlet line 72 is not pre-heated, but fed directly by the separating module 720 to the fuel cell 500. As such, the stream of ammonia and / or hydrogen is provided at a low temperature, such as a temperature less than 100°C, preferably between 60°C and 80°C, to the fuel cell 500. In particular, the stream of hydrogen is provided to the fuel cell 500 using the secondseparator outlet line 72, whereas the stream of ammonia is provided using another outlet line 74, which in this case connects directly the separating module 720 with the fuel cell 500. Additionally, or alternatively, the stream of ammonia can be fed directly to the fuel cell 500 from the ammonia input stream entering into the ammonia cracking reactor 300 and / or the preheater 710 providing sufficient ammonia for the fuel cell 500 needs. The configuration shown in Fig. 12 allows to operate the fuel cell 500 at low temperature while operating the ammonia cracking reactor 300 at low temperature.

[0084] 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 spirt and scope of the claims. In addition, unless specified otherwise herein, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

Claims

CLAIMS1. A power generating system comprising a gas turbine (100), a fuel cell (500), and a gas turbine auxiliary system for NH3 conditioning, wherein the gas turbine auxiliary 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 gas NH3 / H2 / N2 mixture, the gas turbine auxiliary system for NH3 conditioning comprising an ammonia cracking reactor (300), the ammonia cracking reactor (300) being configured to decompose ammonia into a gas mixture of hydrogen, nitrogen and residual ammonia, a separator coupled to said gas turbine (100) and being configured to separate the gas mixture into separate streams of hydrogen, nitrogen, ammonia, said separator comprising at least one of: a first separator outlet line (71, 74) connected to said fuel cell (500) for conveying said stream of ammonia to said fuel cell (500), and a second separator outlet line (72, 72b) connected to said fuel cell (500) for conveying said stream of hydrogen to said fuel cell (500).

2. The power generating system of claim 1, wherein the separator comprises a membrane.

3. The power generating system of claim 1 or 2, further comprising a gas mixture outlet line of the cracking reactor (300) being connected to said separator, and wherein the separator comprises at least one of: a heat exchanger (710); and a separating module (720), preferably wherein the separating module (720) is a Pressure Swing Adsorption, PSA, said separating module being configured to separate the gas mixture using pressure.

4. The power generating system of claim 3, wherein the heat exchanger (710) is configured to provide a cooled gas mixture to the separating module (720).

5. The power generating system of claim 3 or claim 4, wherein the heat exchanger (710) is configured to heat at least one of said stream of ammonia and said stream of hydrogen at a temperature at least sufficient for operating the fuel cell (500) at high temperature.

6. The power generating system of claim 3 or claim 4, wherein the separating module (720) is configured to provide the separated streams of hydrogen and / or ammonia to the fuel cell (500) at a temperature sufficient for operating the fuel cell (500) at low temperature.

7. The power generating system of any one of the preceding claims, further comprising at least one compression system being configured to: adjust a fluid pressure; and convey the fluid outside the system for external uses; wherein said fluid comprises at least one of the gas mixture, the stream of hydrogen, the stream of nitrogen, and the stream of ammonia.

8. The power generating system of any one of the preceding claims, wherein the first separator outlet line (71) comprises an ammonia storage system being arranged along said outlet line (71).

9. The power generating system of any one of the preceding claims, wherein the second separator outlet line (72, 72b) comprises a hydrogen storage system being arranged along said outlet line (72, 72b).

10. The power generating system of any one of the preceding claims, wherein said separator comprises a third separator outlet line (73) connected to said gas turbine (100) for conveying said stream of nitrogen to said gas turbine (100), preferably wherein the third separator outlet line (73) comprises a nitrogen storage system being arranged along said outlet line (73).

11. The power generating system of any one of the preceding claims, wherein the gas turbine (100) comprises a heat recovery steam generator HRSG (110) to recover at least part of the heat of an exhaust gas stream (15) from the gas turbine (100) andconvey said at least part of the heat to said ammonia cracking reactor (300).

12. The power generating system of claim 11, wherein the HRSG (110) comprises a Selective Catalytic Reduction, SCR, system.

13. The power generating system of claim 11 or 12, wherein the HRSG (110) comprises a post-firing module configured to receive and process at least a portion of said stream of hydrogen and / or ammonia to generate additional heat and convey at least part of said additional heat to said ammonia cracking reactor (300).

14. The power generating system of any one of the preceding claims, further comprising a second heat exchanger being configured to preheat an ammonia input stream entering into the ammonia cracking reactor (300) and / or the fuel cell (500) and wherein the gas turbine auxiliary system is configured to generate heat and convey at least part of said heat to said second heat exchanger.

15. The power generating system of any one of the preceding claims, comprising a third heat exchanger (800) to preheat the air entering the fuel cell (500), wherein at least a part of the power generated by the fuel cell (500) is conveyed to said third heat exchanger (800), and preferably wherein a remaining part of the heat generated by the fuel cell (500) is conveyed to said ammonia cracking reactor (300).

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