A gas turbine system equipped with an ammonia cracker, a power plant equipped with the same, and a method for operating the gas turbine system.

Abstract

A gas turbine apparatus comprising an ammonia cracker, a power plant comprising the same, and a method for operating the gas turbine apparatus. The present invention relates to a combustion apparatus for a gas turbine comprising a burner, a combustion chamber, and an ammonia cracker. The ammonia cracker comprises a heating means and a reaction channel, the outlet of the reaction channel being fluidically connected to the combustion chamber, and the inlet of the reaction channel being fluidically connected to an ammonia source. In order to improve efficiency and reduce installation work, a heat transfer section is intended to be used as the heating means, the heat transfer section partially defining the combustion chamber and enabling heat transfer from the combustion chamber to the reaction channel.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a gas turbine arrangement including an ammonia cracker. A gas turbine typically includes a compressor, a combustion section, and an expansion turbine. The ammonia cracker is used to decompose ammonia into a mixture of hydrogen and nitrogen, and the hydrogen can be combusted in the combustion section of the gas turbine.

[0002] [Background Art] Conventionally, natural gas has been used as fuel in many gas turbines. To reduce carbon dioxide emissions, it is preferable to use hydrogen as fuel for gas turbines. However, the supply and storage of hydrogen are costly and raise safety concerns. Therefore, ammonia is a suitable medium for storing and transporting hydrogen from the production site to the power plant.

[0003] Direct combustion of ammonia as fuel for a gas turbine is impossible because an unacceptable amount of nitrogen oxides (NOx) is generated. Furthermore, ammonia is difficult to combust directly due to ignition delay. Therefore, it is necessary to decompose at least part of the ammonia into hydrogen and nitrogen before combustion in the combustion chamber of the gas turbine.

[0004] High temperatures are required to decompose ammonia. In this case, various techniques are used to obtain the required heat in the ammonia cracker.

[0005] Generally, a power plant including ammonia decomposition and gas turbine operation is preferably operated as efficiently as possible with minimal energy waste. Also, it is desirable not to require an external heat source or energy source for ammonia decomposition.

[0006] Exemplary solutions for enabling the combustion of ammonia are disclosed in patent documents EP3314166B1, EP3377745B1, and EP3417205B1. In all of these cases, a portion of the ammonia is supplied to an ammonia cracker, and the resulting hydrogen and nitrogen are further supplied to a combustor of a gas turbine. Advantageously, the heat from the exhaust gases of the gas turbine is used to heat the ammonia cracker.

[0007] When gas turbine exhaust gas is intentionally used in a steam generator to produce steam for a steam turbine, the usable temperature in the steam generator decreases because a significant portion of the heat has already been used in the ammonia cracker.

[0008] [Description of the invention] The object of the present invention is to develop an alternative solution for an ammonia cracker installed in a combustion device that does not significantly reduce the exhaust gas temperature (and therefore allows the exhaust gas to be used in a steam generator). Furthermore, it is required to avoid using external heat sources or external energy sources as much as possible.

[0009] This problem is solved by the inventive combustion device described in claim 1. An inventive gas turbine having a corresponding combustion device is described in claim 10. Inventive methods for operating the combustion device and gas turbine are described in claims 9 and 12. Advantageous embodiments are subject to dependent claims.

[0010] A typical combustion system is preferably used in conjunction with a gas turbine. Independently, this embodiment can also be used in other facilities where ammonia is combusted. In either case, the combustion system comprises at least one burner and one combustion chamber. Depending on the intended use of the combustion system, the burner is supplied with combustion air and fuel. Both of these are supplied through the burner to the combustion chamber, where they can be burned.

[0011] Furthermore, the combustion chamber may have multiple burners. In this case, the embodiment of the present invention can be applied to one or more of the existing burners. Preferably, in this case, the solution of the present invention takes into account all existing burners.

[0012] An ammonia cracker is necessary to decompose ammonia into hydrogen and nitrogen. Therefore, the ammonia cracker has a reaction channel that starts at the ammonia inlet and ends at the fuel outlet. During combustion operation, gaseous ammonia needs to be supplied to the ammonia cracker. For this reason, it is intentionally required to connect the ammonia inlet of the reaction channel to an ammonia supply source.

[0013] To enable the decomposition process, the ammonia cracker must be operated at the required temperature. Therefore, typical ammonia crackers are equipped with a heating mechanism. During operation of the combustion device, the heating mechanism introduces heat to the ammonia passing through the reaction channels. This causes the ammonia to decompose into hydrogen and nitrogen, leaving some undecomposed ammonia.

[0014] In order to burn the hydrogen produced in the ammonia cracker, the fuel outlet of the reaction channel must be fluidly connected to the combustion chamber.

[0015] Depending on the arrangement of the ammonia cracker, fuel piping can be provided between the fuel outlet of the reaction channel and the burner. If multiple burners are provided and the ammonia cracker is located upstream of the burner in the direction of ammonia flow, the fuel piping from the fuel outlet preferably branches to all installed burners.

[0016] To achieve the desired efficiency and reduce installation work, the present invention requires that the heat transfer section form part of the combustion chamber. Combustion within the combustion chamber heats the surrounding wall of the combustion chamber, and as a result, the heat transfer section, which is part of the surrounding wall of the combustion chamber, is also heated. Further heat transfer from the heat transfer section to the reaction channel must then be possible.

[0017] To enable favorable heat transfer from the heat transfer section to the reaction channel, the ammonia cracker is further equipped with a heat conductor. The heat transfer section is either part of the heat conductor or directly attached to the heat conductor, enabling effective heat transfer from the combustion chamber to the reaction channel. Thus, the reaction channel passes through the heat conductor.

[0018] Therefore, the heating means includes a heat conductor and a heat transfer element.

[0019] By effectively utilizing the heat generated by the combustion process within the combustion chamber for the decomposition of ammonia immediately adjacent to the combustion chamber, it is possible to avoid the installation work of piping configurations such as those required when placing an ammonia cracker in the exhaust path. Instead, the decomposed hydrogen and nitrogen can be guided to the combustion chamber via a shorter path.

[0020] When the ammonia cracker is installed directly adjacent to the combustion chamber, it is particularly advantageous because it allows for a shorter distance between the combustion chamber and the reaction channel.

[0021] Preferably, this configuration allows the ammonia to be heated to 600°C or higher during the combustion process. Temperatures exceeding 700°C are particularly preferred.

[0022] If necessary to achieve the temperature required for ammonia decomposition, it is advantageous to provide an ammonia burner as an additional heating means. This ammonia burner is configured to burn a portion of the ammonia supplied to the ammonia cracker together with combustion air within the ammonia cracker.

[0023] Instead of using an external energy source for heating within the ammonia cracker, it is advantageous to directly use ammonia itself as fuel for the ammonia burner as the heating means. Combustion of ammonia can further increase the efficiency of the combustion device.

[0024] The combustion of ammonia in an ammonia cracker is preferably achieved by two different embodiments. In the first embodiment, it is necessary to provide a combustion air nozzle in the reaction channel. By injecting combustion air into the ammonia flow, a portion of the ammonia can be burned directly within the reaction channel. This decomposes the remaining ammonia (i.e., the majority of the supply ammonia not burned by the ammonia burner) into hydrogen and nitrogen, which is particularly advantageous. Obviously, a mixture of hydrogen and nitrogen, as well as residual ammonia and vapor, is then passed through the reaction channel into the combustion chamber.

[0025] In the second embodiment, the ammonia cracker is required to have a heating channel in addition to the reaction channel. Here, the ammonia burner is located on the inlet side of the heating channel, and the outlet side of the heating channel is fluidly connected to the combustion chamber. During operation of the combustion apparatus, combustion air and ammonia need to be supplied to the ammonia burner.

[0026] It is possible to use common piping for both the ammonia inlet and the ammonia burner of the reaction channel. Alternatively, it is possible to supply ammonia to the reaction channel independently of the ammonia burner using separate piping.

[0027] If dedicated piping for the ammonia burner is provided to control the introduction of heat into the reaction channel due to ammonia combustion in the ammonia burner, the ammonia flow rate to the ammonia burner can be controlled. Furthermore, it is also possible to control the flow rate of combustion air to the ammonia burner.

[0028] In order to heat the ammonia in the ammonia cracker to the temperature required for decomposition, it is advantageous for the ammonia supplied to the ammonia cracker to already be at a high temperature. The ammonia supplied from the ammonia source is expected to be at a low temperature compared to the temperature required in the ammonia cracker. On the other hand, the mixture of hydrogen and nitrogen discharged through the ammonia cracker is at a high temperature for the heating required for the decomposition process.

[0029] Here, in order to heat the ammonia supplied to the ammonia cracker, it is advantageous to reuse the heat in the mixture. Therefore, the combustion device preferably includes a fuel heat exchanger. This fuel heat exchanger preferably has a first ammonia passage and a fuel passage.

[0030] The fuel passage of the fuel heat exchanger needs to be fluidly connected to the fuel outlet of the ammonia cracker on the input side. Also, the first ammonia passage of the fuel heat exchanger needs to be fluidly connected to the ammonia inlet of the ammonia cracker on the output side.

[0031] The ammonia source needs to be intentionally fluidly connected to the input side of the first ammonia passage of the fuel heat exchanger. Also, the output side of the fuel passage of the fuel heat exchanger needs to be fluidly connected to at least one burner. Clearly, in this preferred embodiment, the fuel flow (initially as ammonia and then as a mixture of hydrogen and nitrogen) passes through the fuel heat exchanger twice.

[0032] By using a fuel heat exchanger in addition to the ammonia cracker, the heat introduced into the ammonia cracker can be efficiently reused for preheating the ammonia.

[0033] As a further advantageous means for heating the ammonia supplied to the ammonia cracker to a high temperature and then to the required temperature in the ammonia cracker, there is a case where the combustion device includes a fuel preheater.

[0034] The fuel preheater is required to have a second ammonia passage and an air passage. The inlet of the second ammonia passage must be fluidically connected to the ammonia supply source for the operation of the combustion apparatus. If a fuel heat exchanger is installed, the outlet of the second ammonia passage must be fluidically connected to the inlet of the first ammonia passage. If a fuel heat exchanger is not installed, the outlet of the second ammonia passage must be fluidically connected to the ammonia inlet of the reaction channel.

[0035] The outlet of the air passage must be fluidly connected to the combustion chamber. For the operation of the combustion apparatus, the inlet of the air passage must be intentionally fluidly connected to the source of combustion air.

[0036] Combustion air is typically supplied to the combustion apparatus under pressurization. If the combustion air is even hotter during this process, that heat can be used to preheat the ammonia.

[0037] The combustion apparatus of the present invention and its preferred embodiments make it possible to construct an inventive gas turbine. A typical gas turbine comprises a compressor, at least one combustor, and an expansion turbine. In the inventive configuration, the combustion apparatus described above is used as the combustor.

[0038] A compressor has a compressor inlet, multiple compression stages, and a compressor outlet. When a gas turbine is in operation, filtered outside air, which is combustion air, typically flows into the compressor inlet, is compressed, and supplied from the compressor outlet. As a result, the temperature of the compressed air at the compressor outlet increases due to the compression process.

[0039] Various types of combustion devices can be used in the solution of the present invention. An annular combustion chamber with multiple burners arranged around the central axis of a gas turbine can be used. Alternatively, a silo-type combustion system or multiple can-type combustors (each typically having one burner) distributed around the central axis of a gas turbine can be used. In either case, at least a portion of the compressed combustion air is supplied to the combustion device from the compressor outlet. Furthermore, during operation of the gas turbine, fuel must be supplied to at least one burner.

[0040] The expansion turbine is located downstream of the combustion unit and is driven by the flow of high-temperature exhaust gas during gas turbine operation. After the high-temperature exhaust gas expands within the expansion turbine, its temperature is reduced and it is discharged from the output end of the gas turbine.

[0041] When an ammonia cracker is preferably equipped with an ammonia burner, it is advantageous to fluidically connect the ammonia burner to the compressor outlet. This allows a portion of the compressed combustion air to be supplied to the ammonia burner, thereby enabling the combustion of ammonia within the ammonia cracker.

[0042] When a combustion system includes an ammonia preheater, it is advantageous to fluidly connect the inlet of the ammonia preheater's air passage to the compressor outlet. This allows a portion of the compressed combustion air to be supplied to the ammonia preheater, thereby transferring heat from the compressed air to the ammonia.

[0043] The efficiency of the gas turbine can be improved by utilizing the heat from the combustion chamber via a heat transfer section, more preferably by using the combustion of ammonia in an ammonia cracker in combination, more preferably by using the heat of compressed combustion air to preheat the ammonia, and more preferably by reusing the heat of decomposed ammonia to further preheat the ammonia. This allows the high-temperature exhaust gas discharged from the gas turbine to be used to continue operating the steam generator.

[0044] It is possible to supply gaseous ammonia from an ammonia source.

[0045] If the ammonia source supplies liquid ammonia, it is preferable to use an additional ammonia evaporator. The ammonia evaporator must include a fluid passage and an evaporation passage, the evaporation passage of the ammonia evaporator must be fluidically connected to the fuel source on the input side and, in a preferred embodiment, fluidically connected on the output side to the inlet side of the first ammonia passage of a fuel heat exchanger, or (if applicable) the inlet side of the second ammonia passage of a preferred ammonia preheater. [Brief explanation of the drawing]

[0046] [Figure 1] Figure 1 schematically shows an example embodiment of an inventive combustion apparatus 01 comprising a combustion chamber, a burner, and an ammonia cracker. [Figure 2] Figure 2 schematically shows the arrangement of the combustion device 01 in the gas turbine 05 to enable the combustion of ammonia or hydrogen.

[0047] [Description of Embodiments] Figure 1 shows an inventive combustion apparatus 01 having an example arrangement of an ammonia cracker 11. The combustion apparatus 01 comprises a combustion chamber 03 and, exemplary, two burners 02. When the combustion apparatus is in operation, the burners 02 are supplied with fuel, i.e., a mixture containing hydrogen, and combustion air. The fuel and combustion air are introduced into the combustion chamber 03 and combusted.

[0048] A key feature in implementation is that the ammonia cracker 11 is positioned adjacent to the combustion chamber 03. This allows the heat transfer section 13 to form part of the outer wall of the combustion chamber 03. This configuration allows some of the heat generated in the combustion chamber 03 during hydrogen combustion to be transferred to the heat transfer section 13.

[0049] The ammonia cracker 11 is equipped with a reaction channel 12 that penetrates through the ammonia cracker 11 from the ammonia inlet to the fuel outlet. Furthermore, the ammonia cracker 11 is equipped with a heating means, and the heat transfer section 13 that forms part of the combustion chamber 03 constitutes part of this heating means.

[0050] Heat can be intentionally transferred from the heat transfer section 13 to the reaction channel 12. Therefore, in this embodiment, the ammonia cracker 11 is further equipped with a heat conductor 14, and the heat transfer section 13 constitutes a part of the heat conductor 14 at the boundary between the ammonia cracker 11 and the combustion chamber 03.

[0051] To introduce additional heat into the reaction channel 12, the ammonia cracker 11 is further equipped with an ammonia burner 15. In this exemplary embodiment, the ammonia burner 15 is located at the ammonia inlet of the reaction channel 12. During operation of the combustion apparatus, ammonia and combustion air are supplied to the ammonia burner. This causes the ammonia to partially burn and the temperature to rise.

[0052] This exemplary configuration further includes a fuel heat exchanger 21 having a first ammonia passage 22 and a fuel passage 23. Ammonia is supplied to the inlet side of the first ammonia passage 22 and, after heating, is led from the outlet side of the first ammonia passage 22 to the ammonia inlet of the reaction channel 12 of the ammonia cracker 11.

[0053] The decomposition fuel, as a mixture of hydrogen, nitrogen, and residual ammonia, and the gas produced by the combustion of ammonia, particularly including vapor, are guided from the fuel outlet of the reaction channel 12 to the inlet side of the fuel passage 23 of the fuel heat exchanger 21. The fuel mixture is further guided from the outlet side of the fuel passage 23 to the burner, enabling the combustion of hydrogen in the combustion chamber.

[0054] Furthermore, an ammonia preheater 24 is positioned upstream (forward in the flow direction) of the fuel heat exchanger 21. Combustion air is intentionally flowed through the air passage in the ammonia preheater 24 to heat the ammonia passing through the second ammonia passage in the preheater. As a result, ammonia is supplied to the inlet side of the second ammonia passage and guided from the outlet side to the inlet side of the first ammonia passage 22 with its temperature increased.

[0055] To enable the supply of gaseous ammonia, an ammonia evaporator 25, which can supply liquid ammonia from an ammonia supply source 04, is located upstream of the ammonia preheater 24 in the flow direction.

[0056] Figure 2 shows an example embodiment of a gas turbine 05 equipped with the combustion device 01 shown in Figure 1. The gas turbine 05 comprises a compressor, a combustion device 01 (represented in a simplified box shape as shown in Figure 1), and an expansion turbine 07.

[0057] During operation of the gas turbine 05, the heated compressed air is guided from the compressor outlet to the inlet side of the air passage in the ammonia preheater 24. The combustion air and further preheated ammonia are then guided from the ammonia preheater 24 to the combustion device 01.

[0058] After some of the ammonia and decomposed hydrogen are burned in the combustion device 01, the exhaust gas passes through the expansion turbine 07, which normally drives the rotor to power the generator.

[0059] It should be noted that the fuel heat exchanger 21 and ammonia preheater 24 shown herein can be located separately from the combustion device 01 via the necessary piping.

[0060] Furthermore, by positioning the fuel heat exchanger 21 adjacent to or near the ammonia cracker 11, piping work can be reduced, and the heat inside the system can be utilized to the maximum extent.

[0061] Furthermore, the ammonia preheater 24 can be positioned adjacent to or near the ammonia cracker 11 or the combustion chamber 03. This makes it possible to first guide at least a portion of the combustion air along the combustion chamber for cooling purposes, and then introduce the further heated combustion air into the ammonia preheater 24.

Claims

1. A combustion apparatus (01) for a gas turbine, comprising at least one burner (02) and a combustion chamber (03), wherein combustion air and fuel are intentionally supplied to the burner (02) and burned in the combustion chamber (03), Furthermore, the combustion apparatus (01) comprises an ammonia cracker (11) having a heating means and a reaction channel (12), the outlet of the reaction channel (12) being fluidly connected to the burner (02), and ammonia being intentionally supplied from an ammonia supply source to the inlet of the reaction channel (12), The heating means includes a heat conductor (14) and a heat transfer section (13), the reaction channel (12) traversing the heat conductor (14), the heat transfer section (13) forming part of the combustion chamber (03), and enabling heat transfer from the combustion chamber (03) to the reaction channel (12). A combustion device characterized by the following features.

2. The ammonia cracker is positioned adjacent to the combustion chamber. The combustion apparatus (01) according to claim 1.

3. The heating means further comprises an ammonia burner (15), and combustion air and ammonia are intentionally supplied to the ammonia burner (15) and burned in the ammonia cracker (11). The combustion apparatus (01) according to claim 1 or 2.

4. The ammonia burner (15) is equipped with a combustion air nozzle, enabling the combustion of ammonia within the reaction channel (12). The combustion apparatus (01) according to claim 3.

5. The ammonia cracker (11) comprises a heating channel separated from the reaction channel, the ammonia burner is located on its inlet side, and its outlet side is connected to the combustion chamber (03). The combustion apparatus (01) according to claim 3.

6. The system further comprises a fuel heat exchanger (21) having a fuel passage (23) and a first ammonia passage (22), The outlet of the first ammonia passage (22) is fluidly connected to the ammonia cracker (11), ammonia is intentionally supplied to the inlet of the first ammonia passage (22), the inlet of the fuel passage (23) is fluidly connected to the outlet of the reaction channel (12), and the outlet of the fuel passage (23) is fluidly connected to the burner (02). A combustion apparatus (01) according to any one of claims 1 to 5.

7. The ammonia preheater (24) further comprises a second ammonia passage and an air passage, The outlet of the second ammonia passage is fluidically connected to the inlet of the first ammonia passage (22) or the ammonia inlet of the reaction channel (12), and ammonia is intentionally supplied to the inlet of the second ammonia passage. The outlet of the air passage is fluidically connected to the burner (02), and combustion air is intentionally supplied to the inlet of the air passage. The combustion apparatus (01) according to claim 6.

8. A method for operating a combustion apparatus (01) according to any of the above claims, wherein ammonia is supplied by an ammonia source, passes through the reaction channel (12), is at least partially decomposed therein into hydrogen and nitrogen, is supplied to the burner (02) and combusted in the combustion chamber (03), A method in which the thermal energy generated by the combustion is partially transferred from the heat transfer section (13) to the heat conductor (14), and further to the ammonia passing through the reaction channel (12).

9. A gas turbine (05) comprising a compressor (06), a combustion device (01) according to any of the claims, and an expansion turbine (07).

10. The outlet of the compressor (06) is fluidly connected to the ammonia burner (15). The gas turbine (05) according to claim 9.

11. The outlet of the compressor (06) is fluidly connected to the air passage of the ammonia preheater (24). The gas turbine (05) according to claim 9 or 10.

12. A method for operating a gas turbine (05) having a gas turbine (05) as described in any of the preceding claims, The combustion air is compressed and heated by the compressor (06) and guided through the air passage. A portion of the compressed air is supplied to the burner (02), and the other portion is supplied to the ammonia burner (15). Additional heat is introduced into the ammonia cracker (11) by the combustion of ammonia, Ammonia is supplied to the ammonia inlet of the reaction channel (12), heated and decomposed into hydrogen and nitrogen, and then guided from the outlet of the reaction channel (12) to the burner (02) as fuel gas. The steps include: burning hydrogen in the combustion chamber (03), and A method comprising the step of guiding the resulting exhaust gas from the combustion chamber (03) through the expansion turbine (07).

13. Compressed and heated combustion air is at least partially guided from the outlet of the compressor (06) into the air passage. The method according to claim 12.

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