Gas turbine plant having ammonia cracker, power plant having such plant, and method for operating gas turbine plant

Abstract

The invention relates to a combustion device (01) of a gas turbine, comprising a burner (02), a combustion chamber (03) and an ammonia cracker (11). The ammonia cracker comprises a heating device and a reaction channel (12), where an outlet of the reaction channel is in fluid connection with the combustion chamber and an inlet of the reaction channel is configured to be in fluid connection with an ammonia source. In order to improve efficiency and reduce installation work, it is desirable to use a transfer part (13) as a heating device, which defines parts of the combustion chamber and enables heat transfer from the combustion chamber to the reaction channel.

Description

Technical Field

[0001] This invention relates to a gas turbine unit including an ammonia cracker. A gas turbine typically includes a compressor, a combustion section, and an expansion turbine. The ammonia cracker is used to crack ammonia into a mixture of hydrogen and nitrogen, wherein the hydrogen can be burned in the combustion section of the gas turbine. Background Technology

[0002] Natural gas is typically used as fuel in most gas turbines. To reduce carbon dioxide emissions, hydrogen is preferred as fuel for gas turbines. However, the supply and storage of hydrogen are expensive and pose safety concerns. Therefore, ammonia is the preferred medium for storing hydrogen and transporting it from the production site to the power plant.

[0003] Direct combustion of ammonia as fuel in a gas turbine is impossible due to the release of unacceptable amounts of nitrogen oxides (NOx). Furthermore, ammonia is difficult to burn directly due to its ignition inertness. Therefore, at least a portion of ammonia must be cracked into hydrogen and nitrogen before combustion in the gas turbine's combustion chamber.

[0004] High temperatures are required to crack ammonia. Various technologies are used to achieve the heat needed within the ammonia cracker.

[0005] Generally, it is preferable to operate the power generation equipment, including ammonia cracking and gas turbine operation, as efficiently as possible while minimizing energy waste. Secondly, it is preferable that no external heat source or energy source is required to crack the ammonia.

[0006] Exemplary solutions capable of burning ammonia are given in EP3314166B1, EP3377745B1 and EP3417205B1. In all cases, a portion of the ammonia is supplied to the ammonia cracker, and the resulting hydrogen and nitrogen are further supplied to the combustor of the gas turbine. Advantageously, heat from the exhaust gas from the gas turbine is used to heat the ammonia cracker.

[0007] If the exhaust gas from the gas turbine is intentionally used in the steam generator to generate steam for another steam turbine, only a reduced temperature can be obtained in the steam generator because the relevant heat share has already been used for the ammonia cracker. Summary of the Invention

[0008] The objective of this invention is to develop an alternative solution for ammonia crackers installed in combustion devices without consequently reducing exhaust gas temperature (thus enabling the use of exhaust gas in steam generators). Furthermore, the use of external heat or external energy sources should be avoided as much as possible.

[0009] This objective is achieved by the inventive combustion device according to claim 1. Claim 10 defines an inventive gas turbine having a corresponding combustion device. Claims 9 and 12 provide inventive methods for operating the combustion device and the gas turbine. Advantageous embodiments are the subject of the dependent claims.

[0010] Conventional combustion devices are conveniently used in gas turbines. Independently, this embodiment can be used for other facilities providing ammonia combustion. In any case, the combustion device includes at least one burner and a combustion chamber. Depending on the intended use of the combustion device, combustion air and fuel are supplied to the burner. Both are supplied through the burner to the combustion chamber, where they can be combusted accordingly.

[0011] Furthermore, it is possible to provide that multiple burners are arranged in the combustion chamber. In this case, the embodiment according to the invention can be applied to one or more existing burners. Preferably, in this case, the solution according to the invention takes into account all existing burners.

[0012] An ammonia cracker is required to break down ammonia into hydrogen and nitrogen. Therefore, the ammonia cracker has a reaction channel that begins at the ammonia inlet and terminates at the fuel outlet. During the operation of the combustion unit, gaseous ammonia needs to be supplied to the ammonia cracker. Intentionally, the ammonia inlet of the reaction channel needs to be connected to the ammonia source.

[0013] In order for the cracking process to take place, the ammonia cracker needs to be operated at the required temperature. Therefore, a general-purpose ammonia cracker has a heating device. During operation of the combustion unit, the heating device introduces heat into the ammonia passing through the reaction channel. This causes the ammonia to split into hydrogen and nitrogen, while a portion of the ammonia remains.

[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, a fuel line between the fuel outlet of the reaction channel and the burner can be utilized. If several burners are provided and the ammonia cracker is arranged before the burners along the direction of ammonia flow, then it is obvious that the fuel line from the fuel outlet preferably branches to all the installed burners.

[0016] To achieve optimal efficiency and reduce installation work, it is creatively required that the heat transfer section be integrated into the combustion chamber. Combustion within the combustion chamber heats the walls surrounding the combustion chamber, and consequently, the heat transfer section, which is part of the combustion chamber's surrounding walls, is also heated. Further heat transfer from the heat transfer section to the reaction channel must then be achieved.

[0017] To facilitate advantageous heat transfer from the transfer section to the reaction channel, the ammonia cracker also includes a heat conductor. Therefore, the transfer section is either part of or directly attached to the heat conductor to enable beneficial heat transfer from the combustion chamber to the reaction channel. The reaction channel thus passes through the heat conductor.

[0018] Therefore, the heating device includes a heat conductor and a heat transfer component.

[0019] By advantageously utilizing the heat generated by the combustion process within the combustion chamber to directly decompose ammonia, the installation and piping work required for ammonia crackers, such as those installed in the exhaust path, can be avoided. Instead, the cracked hydrogen and nitrogen can be guided into the combustion chamber via a short path.

[0020] A particular advantage is that if the ammonia cracker is installed directly adjacent to the combustion chamber, the distance between the combustion chamber and the reaction channel can be shortened.

[0021] Preferably, this arrangement enables the ammonia to be heated to temperatures above 600°C during the combustion process. Temperatures above 700°C are particularly advantageous.

[0022] If the required temperature for ammonia cracking needs to be reached, an ammonia burner can be advantageously added as an additional heating device. The ammonia burner is intentionally configured to burn a portion of the ammonia supplied to the ammonia cracker with combustion air within the cracker.

[0023] Instead of using an external energy source to heat the ammonia cracker, ammonia can advantageously be used directly as fuel for the ammonia burner, which serves as the heating element. The combustion of ammonia allows for further improvements in the efficiency of the combustion unit.

[0024] Combustion of ammonia within an ammonia cracker can preferably be achieved using two different embodiments. The first embodiment requires a combustion air nozzle positioned at the reaction channel. Injecting combustion air into the ammonia stream allows a portion of the ammonia to burn directly within the reaction channel. Particularly advantageously, this results in the splitting of the remaining ammonia (the larger portion of the supplied ammonia that is not burned by the ammonia burner) into hydrogen and nitrogen. Obviously, the hydrogen and nitrogen, along with a possible mixture of remaining ammonia and vapor, exit the reaction channel and are directed into the combustion chamber.

[0025] In the second embodiment, in addition to the reaction channel, the ammonia cracker also requires a heating channel. Here, the ammonia burner is arranged on the input side of the heating channel, and the output side of the heating channel is fluidly connected to the combustion chamber. During the operation of the combustion device, combustion air and ammonia need to be supplied to the ammonia burner.

[0026] A common conduit can be used, connecting the ammonia inlet to the reaction channel and the ammonia burner. Alternatively, ammonia can be supplied to the reaction channel, separate from the ammonia burner, via a separate conduit.

[0027] In order to control the introduction of heat into the reaction channel by burning ammonia at the ammonia burner, the flow of ammonia to the ammonia burner can be controlled if a dedicated pipeline is provided to the ammonia burner. Next, the flow of combustion air to the ammonia burner can be controlled.

[0028] In order to heat the ammonia in the ammonia cracker to the temperature required for ammonia cracking, it is advantageous if the ammonia supplied to the cracker is already at an elevated temperature. It can be anticipated that the ammonia supplied from the ammonia source has a lower temperature compared to the temperature required within the cracker. On the other hand, due to the heating required within the cracker for the cracking process, the mixture of hydrogen and nitrogen leaving the cracker has a high temperature.

[0029] Advantageously, the heat in the mixture is reused to heat the ammonia supplied to the ammonia cracker. Therefore, the combustion device advantageously includes a fuel heat exchanger. The fuel heat exchanger should have 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 output of the ammonia cracker on the input side. The first ammonia passage of the fuel heat exchanger needs to be fluidly connected to the ammonia input 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, wherein 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 stream (first ammonia, then a mixture of hydrogen and nitrogen) flows through the fuel heat exchanger twice.

[0032] In addition to the ammonia cracker, the use of a fuel heat exchanger makes it possible to effectively reuse the heat introduced into the ammonia cracker to preheat the ammonia.

[0033] If the advantageous combustion device includes a fuel preheater, then by supplying ammonia to the ammonia cracker at an elevated temperature, a further advantageous possibility is provided for heating the ammonia in the ammonia cracker to the temperature required for cracking the ammonia.

[0034] The fuel preheater is required to have a second ammonia passage and an air passage. The inlet of the second ammonia passage needs to be fluidly connected to an ammonia source to operate the combustion device. If a fuel heat exchanger is installed, the outlet of the second ammonia passage needs to be fluidly connected to the inlet of the first ammonia passage. If a fuel heat exchanger is not anticipated, the outlet of the second ammonia passage needs to be fluidly connected to the ammonia inlet of the reaction channel.

[0035] The air passage outlet must be fluidly connected to the combustion chamber. For the operation of the combustion device, it is intentionally necessary to fluidly connect the air passage inlet to the combustion air source.

[0036] Combustion air is typically supplied to the combustion unit at increased pressure. If the temperature of the combustion air rises further during the process, the heat from the combustion air can be used to preheat the ammonia.

[0037] The combustion device of the present invention and its preferred embodiments are capable of constructing innovative gas turbines. A typical gas turbine includes a compressor, at least one combustor, and an expansion turbine. The combustion device described above is innovatively used as a combustor.

[0038] A compressor has a compressor inlet, several compressor stages, and a compressor outlet. During gas turbine operation, combustion air (typically filtered ambient air) flows into the compressor inlet, is compressed, and is supplied from the compressor outlet. As a result, the compressed combustion air at the compressor outlet has an elevated temperature due to the compression process.

[0039] Different types of combustion devices can be used in the solutions of this invention. An annular combustion chamber with multiple burners distributed around the central axis of the gas turbine can be used. Alternatively, a silo combustion system or multiple canister burners distributed around the central axis of the gas turbine can be used, typically each canister burner having one burner. In any case, compressed combustion air is supplied to the combustion device at least partially from the compressor outlet. Additionally, during gas turbine operation, fuel needs to be supplied to at least one burner of the combustion device.

[0040] The expansion turbine is located downstream of the combustion unit and is driven by the flow of hot exhaust gas during gas turbine operation. After the hot exhaust gas expands in the expansion turbine, it exits the expansion turbine at a reduced temperature at the gas turbine's output.

[0041] If the ammonia cracker includes a preferred ammonia burner, it is advantageous to connect the ammonia burner to the compressor outlet fluidly, so that a portion of the compressed combustion air can be supplied to the ammonia burner so that the ammonia can be burned within the ammonia cracker.

[0042] If the combustion device includes an ammonia preheater, it is advantageous to connect the inlet of the air passage of the ammonia preheater to the compressor outlet fluidly, so that a portion of the compressed combustion air can be supplied to the ammonia preheater to transfer the heat in the compressed combustion air to the ammonia.

[0043] By using heat transferred from the combustion chamber, preferably additionally burning ammonia in the ammonia cracker, preferably preheating ammonia by using the heat of compressed combustion air, and preferably further utilizing the heat of cracked ammonia to further preheat ammonia, the efficiency of the gas turbine can be improved, so that the hot exhaust gas leaving the gas turbine can still be used for the operation of the steam generator.

[0044] Ammonia can be provided in gaseous form through an ammonia source.

[0045] If the ammonia source provides ammonia in liquid form, it is preferable to use an additional ammonia evaporator. The ammonia evaporator should include a fluid passage and a vapor passage, wherein the vapor passage of the ammonia evaporator is fluidly connected to the fuel source on the inlet side and fluidly connected to the inlet side of a first ammonia passage of a preferred fuel heat exchanger, or (if provided) fluidly connected to the inlet side of a second ammonia passage of a preferred ammonia preheater. Attached Figure Description

[0046] Figure 1 An exemplary embodiment of the combustion apparatus 01 of the present invention, having a combustion chamber, a burner, and an ammonia cracker, is schematically shown.

[0047] Figure 2 The arrangement of the combustion device 01 in the gas turbine 05 is schematically shown to enable the separate combustion of ammonia and hydrogen. Detailed Implementation

[0048] exist Figure 1 The diagram illustrates an exemplary arrangement of the combustion apparatus 01 of the present invention, featuring an ammonia cracker 11. The combustion apparatus 01 includes a combustion chamber 03 and two burners 02 as illustrated. During operation of the combustion apparatus, the burners 02 are supplied with fuel, i.e., a mixture comprising hydrogen, and combustion air. The fuel and combustion air are introduced into the combustion chamber 03 and combusted.

[0049] Related to the implementation is the arrangement of the ammonia cracker 11 adjacent to the combustion chamber 03. Therefore, the transfer section 13 partially defines the surrounding wall of the combustion chamber 03. Due to this arrangement, the heat generated within the combustion chamber 03 during hydrogen combustion is partially transferred to the transfer section 13.

[0050] The ammonia cracker 11 includes a reaction channel 12 that extends from the ammonia input end through the ammonia cracker 11 to the fuel output end. Next, the ammonia cracker 11 includes a heating device, wherein a transfer section 13 that partially defines the combustion chamber 03 is part of this heating device.

[0051] Heat can be intentionally transferred from the transfer portion 13 to the reaction channel 12. Therefore, in this embodiment, the ammonia cracker 11 also includes a heat conductor 14, wherein the transfer portion 13 is a part of the heat conductor 14 at the boundary between the ammonia cracker 11 and the combustion chamber 03.

[0052] To introduce additional heat into the reaction channel 12, the ammonia cracker 11 also includes an ammonia burner 15. In this exemplary embodiment, the ammonia burner 15 is arranged at the ammonia inlet of the reaction channel 12. During operation of the combustion device, ammonia is supplied to the ammonia burner, and combustion air is also supplied. This results in partial combustion of the ammonia and an increase in temperature.

[0053] An exemplary embodiment also includes a fuel heat exchanger 21 having a first ammonia passage 22 and a fuel passage 23. Ammonia is supplied to the input side of the first ammonia passage 22 and, after heating, is directed from the output side of the first ammonia passage 22 to the ammonia input end of the reaction channel 12 of the ammonia cracker 11.

[0054] The cracked fuel, a mixture of hydrogen, nitrogen, and the remainder ammonia, along with gases (especially steam) produced by the combustion of ammonia, is guided from the fuel outlet of reaction channel 12 to the inlet of fuel passage 23 of fuel heat exchanger 21. The fuel mixture is further guided from the outlet of fuel passage 23 to the burner so that hydrogen can be burned in the combustion chamber.

[0055] Furthermore, the ammonia preheater 24 is arranged upstream of the fuel heat exchanger 21 along the flow direction. Combustion air is intentionally guided through the air passage in the ammonia preheater 24 to heat the ammonia passing through the second ammonia passage in the ammonia preheater 24. Thus, ammonia is supplied to the input side of the second ammonia passage and, as the temperature increases, is further guided from the output side of the second ammonia passage to the input side of the first ammonia passage 22.

[0056] In order to supply gaseous ammonia, an ammonia evaporator 25 is shown along the flow direction before the ammonia preheater 24, wherein liquid ammonia can be supplied from the ammonia source 04.

[0057] exist Figure 2 In, it is shown that there is a basis Figure 1 An exemplary embodiment of the gas turbine 05 with combustion device 01. The gas turbine 05 includes a compressor, combustion device 01 (such as...) Figure 1 (Simplified box shown in the image) and expansion turbine 07.

[0058] During the operation of gas turbine 05, the heated compressed air is guided from the compressor outlet to the input side of the air passage within ammonia preheater 24. Combustion air and further preheated ammonia are then guided from ammonia preheater 24 to combustion unit 01.

[0059] After a portion of ammonia and cracked hydrogen are burned in the combustion device 01, the flue gas is guided through the expansion turbine 07 to sequentially drive the rotor to drive the generator.

[0060] It should be noted that the fuel heat exchanger 21 and the ammonia preheater 24 shown can be arranged separately from the combustion device 01, with the required piping arranged between them.

[0061] The fuel heat exchanger 21 can also be arranged close to the ammonia cracker 11 to reduce pipeline work and make full use of the heat in the system.

[0062] Next, the ammonia preheater 24 can be arranged adjacent to or close to the ammonia cracker 11 or the combustion chamber 03. Thus, at least a portion of the combustion air can be initially guided along the combustion chamber for cooling purposes, and then further heated combustion air can be introduced into the ammonia preheater 24.

Claims

1. A combustion device (01), particularly a gas turbine, comprising at least one burner (02) and a combustion chamber (03), wherein combustion air and fuel are configured to be supplied to the burner (02) and combusted in the combustion chamber (03); further comprising an ammonia cracker (11) having a heating device and a reaction passage (12); wherein the outlet of the reaction passage (12) is fluidly connected to the burner (02), wherein ammonia is configured to be supplied from an ammonia source to the inlet of the reaction passage (12); in, The heating device includes a heat conductor (14) and a transfer portion (13), wherein the reaction channel (12) passes through the heat conductor (14) and the transfer portion (13) forms part of the combustion chamber (03) and allows heat to be transferred from the combustion chamber (03) to the reaction channel (12).

2. The combustion device (01) according to claim 1, wherein, The ammonia cracker is arranged adjacent to the combustion chamber.

3. The combustion device (01) according to claim 1 or 2, wherein, The heating device also includes an ammonia burner (15), wherein combustion air and ammonia are configured to be supplied to the ammonia burner (15) and burned within the ammonia cracker (11).

4. The combustion device (01) according to claim 3, wherein, The ammonia burner (15) includes a combustion air nozzle that is capable of burning ammonia within the reaction channel (12).

5. The combustion device (01) according to claim 3, wherein, The ammonia cracker (11) includes a heating channel separate from the reaction channel, wherein the ammonia burner is arranged on its input side and connected to the combustion chamber (03) on its output side.

6. The combustion apparatus (01) according to any one of claims 1 to 5, further comprising a fuel heat exchanger (21) having a fuel passage (23) and a first ammonia passage (22), wherein the output of the first ammonia passage (22) is fluidly connected to the ammonia cracker (11), and ammonia is configured to be supplied to the input of the first ammonia passage (22) and the input of the fuel passage (23) is fluidly connected to the output of the reaction channel (12), and the output of the fuel passage (23) is fluidly connected to the burner (02).

7. The combustion apparatus (01) according to claim 6 further includes an ammonia preheater (24) having a second ammonia passage and an air passage, wherein the output end of the second ammonia passage is fluidly connected to the input end of the first ammonia passage (22) or to the ammonia input end of the reaction channel (12), and ammonia is configured to be supplied to the input end of the second ammonia passage, and the output end of the air passage is fluidly connected to the burner (02), and combustion air is configured to be supplied to the input end of the air passage.

8. A method for operating a combustion device (01) according to any one of the preceding claims, wherein, Ammonia is supplied from an ammonia source and passed through a reaction channel (12), where it is at least partially split into hydrogen and nitrogen and supplied to the burner (02), where it is burned in the combustion chamber (03). The heat generated by the combustion is partially transferred from the transfer portion (13) to the heat conductor (14) and further transferred to the ammonia flowing through the reaction channel (12).

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

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

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

12. A method of operating a gas turbine (05) having a gas turbine (05) according to any one of the preceding claims, wherein, The compressor (06) compresses and heats the combustion air and guides the combustion air through the air passage; A portion of the compressed air is supplied to the burner (02) and another portion is supplied to the ammonia burner (15). Additional heat is introduced into the ammonia pyrolyzer (11) by burning ammonia. Ammonia is supplied to the ammonia inlet of the reaction channel (12) and heated and cracked into hydrogen and nitrogen, which are then directed from the outlet of the reaction channel (12) to the burner (02) as fuel gas. Hydrogen gas is burned in the combustion chamber (03); as well as The generated flue gas is guided from the combustion chamber (03) through the expansion turbine (07).

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

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