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

Abstract

A gas turbine apparatus equipped with an ammonia cracker, a power plant equipped with such a gas turbine apparatus, and a method for operating a gas turbine apparatus. The present invention relates to a gas turbine system (01) comprising a gas turbine and an ammonia cracker. The gas turbine comprises a compressor (02), a combustor (03), a high-pressure expansion turbine (04), and a low-pressure expansion turbine (05). The ammonia cracker (11) comprises a cracker air channel from a cracker air inlet to a cracker air outlet, and a cracker reaction channel from a cracker ammonia inlet to a cracker fuel outlet, the cracker fuel outlet being connected to the combustor (03) by a fuel pipe. To improve the efficiency of the gas turbine system, the ammonia cracker (11) is positioned between the high-pressure expansion turbine (04) and the low-pressure expansion turbine (05), and exhaust gas passes through the cracker air channel during operation.

Description

Technical Field

[0001] The present invention relates to a gas turbine device including an ammonia cracker. A gas turbine generally 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, where the hydrogen can be combusted in the combustion section of the gas turbine.

Background Art

[0002] Conventionally, natural gas has been mostly used as the fuel for gas turbines. In order to reduce the amount of carbon dioxide, it is desirable to use hydrogen as the fuel for gas turbines. The supply and storage of hydrogen are costly and also raise safety concerns. Therefore, ammonia is preferred as a medium for storing and transporting hydrogen from the production site to the power plant.

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

[0004] High temperature is required to decompose ammonia. Here, very different technologies are used to obtain the necessary heat in the ammonia cracker.

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

[0006] Exemplary solutions for enabling ammonia combustion are shown in EP3314166B1, EP3377745B1, and EP3417205B1. In each case, some of the ammonia is supplied to an ammonia cracker, and the resulting hydrogen and nitrogen are further supplied to the combustor of a gas turbine. An advantage is that the heat from the exhaust gases of the gas turbine is used to heat the ammonia cracker. However, known solutions always require a high amount of installation work. [Overview of the Initiative]

[0007] The current challenge of this invention is to develop a highly efficient and low-installation alternative solution for ammonia crackers installed in gas turbines. Furthermore, the use of external heat and external energy sources should be avoided as much as possible.

[0008] This problem is solved by the gas turbine apparatus of the present invention according to claim 1. A method of the present invention for operating a gas turbine apparatus equipped with an ammonia cracker is defined in claim 7. Advantageous embodiments are subject to dependent claims.

[0009] The gas turbine system comprises a gas turbine having a compressor, at least one combustor, and an expansion turbine, the expansion turbine being further divided into a high-pressure expansion turbine connected to the compressor and a low-pressure expansion turbine.

[0010] In the operation of a gas turbine, combustion air, which is usually filtered outside air, is compressed by a compressor and supplied to at least one combustor. In the combustor, fuel is burned, and the hot exhaust gas is guided through a high-pressure expansion turbine and then flows through a downstream low-pressure expansion turbine.

[0011] Furthermore, the gas turbine system requires at least one ammonia cracker, which includes a cracker air channel and a cracker reaction channel. When the gas turbine system is in use, ammonia is supplied to the cracker reaction channel, and the outlet of the cracker reaction channel is connected to the combustor by fuel piping.

[0012] An efficient cracking process is made possible by placing an ammonia cracker between a high-pressure expansion turbine and a low-pressure expansion turbine. During gas turbine operation, exhaust gases pass through the cracker air channel. Detailed description of the invention

[0013] A typical gas turbine system consists of a gas turbine and an ammonia cracker.

[0014] A typical gas turbine comprises a compressor, at least one combustor, and an expansion turbine, the expansion turbine being further divided into a high-pressure expansion turbine and a low-pressure expansion turbine. Typically, the high-pressure expansion turbine is connected to the compressor by a common rotor (the compressor is driven by the high-pressure expansion turbine).

[0015] In the operation of a gas turbine, combustion air, which is normally filtered outside air, is compressed by a compressor and supplied to at least one combustor.

[0016] Various types of combustion arrangements can be used in the solution of the present invention. It is also possible to use an annular combustion chamber in which multiple burners are arranged around the central axis of the gas turbine. Alternatively, a silo combustion system or a can combustor, which usually has one burner and is arranged in multiples around the central axis of the gas turbine, can also be used.

[0017] During operation of a gas turbine, fuel must be supplied to at least one burner in at least one combustor, and this fuel is burned in at least one combustor to generate a flow of hot exhaust gases.

[0018] The high-pressure expansion turbine is located downstream of at least one combustor and is driven by the flow of hot exhaust gases when the gas turbine is in operation.

[0019] A low-pressure expansion turbine is positioned downstream of the high-pressure expansion turbine. After the hot exhaust gas expands in the low-pressure expansion turbine, the exhaust gas leaves the expansion turbine at a reduced temperature at the output terminal of the gas turbine.

[0020] A typical ammonia cracker is necessary to decompose ammonia into hydrogen and nitrogen. Therefore, an ammonia cracker has a cracker reaction channel that begins at the cracker ammonia inlet and ends at the cracker fuel outlet. To operate a gas turbine system, the cracker ammonia inlet must be connected to an ammonia supply. The fuel piping connects the cracker fuel outlet to at least one combustor. If multiple burners are present, it is obviously desirable to branch the fuel piping to all burners where it is installed.

[0021] The ammonia cracker further has a cracker air channel that extends from the cracker air inlet to the cracker air outlet. During operation of the gas turbine system, the flow of high-temperature fluid through the air channel allows for heat transfer from the high-temperature fluid to the reaction channel.

[0022] To enable the cracking process, it is necessary to operate the ammonia cracker at the required temperature. To achieve the desired efficiency and reduce installation work, the present invention plans to position the ammonia cracker between the high-pressure expansion turbine and the low-pressure expansion turbine. As a result, the cracker air inlet is located downstream of the outlet side of the high-pressure expansion turbine, and the ammonia cracker air outlet is located upstream of the inlet side of the low-pressure expansion turbine.

[0023] Here, the hot exhaust gas coming from the high-pressure expansion turbine is guided through the cracker air channel of the ammonia cracker and then further sent to the low-pressure expansion turbine. At this time, part of the heat of the exhaust gas is transferred to the ammonia flowing through the cracker reaction channel.

[0024] In the first embodiment, advantageously, one ammonia cracker is used between the high-pressure expansion turbine and the low-pressure expansion turbine.

[0025] This solution is particularly advantageous when the ammonia cracker is used to supply only a mixture of hydrogen and nitrogen to the same gas turbine without substantially releasing fuel to the outside of the gas turbine device.

[0026] In yet another embodiment, advantageously, two or more ammonia crackers are installed between the high-pressure expansion turbine and the low-pressure expansion turbine. Each ammonia cracker is equipped with a cracker reaction channel and a cracker air channel. During the operation of the gas turbine device, ammonia is supplied to each ammonia inlet of the cracker reaction channel, and a mixture of hydrogen and nitrogen is supplied from the cracker fuel outlet of each cracker reaction channel.

[0027] Here, the ammonia crackers should be arranged sequentially (in series), so that the high-temperature exhaust gas can flow through the cracker air channels of each ammonia cracker in turn.

[0028] This solution is particularly advantageous when hydrogen is to be supplied to other facilities outside the gas turbine device. For example, a plurality of other gas turbines can be supplied without the need for additional ammonia crackers for hydrogen supply.

[0029] An ammonia cracker usually has a heater to heat ammonia to a temperature required to decompose ammonia into hydrogen and nitrogen. If only one ammonia cracker is installed, the heat of the exhaust gas downstream of the high-pressure expansion turbine should be sufficient to carry out the decomposition process. Therefore, no additional heater should be required.

[0030] When two or more ammonia crackers are installed, it may be necessary to increase the heat inside the exhaust gas to enable the decomposition process and supply sufficient energy transfer in the low-pressure expansion turbine. Therefore, it is advantageous to provide a heater in at least one ammonia cracker, preferably in the last ammonia cracker located downstream with respect to the flow direction of the exhaust gas.

[0031] By utilizing the heat of compressed air and further heating with a heater, the efficiency of the gas turbine device can be improved, and thereby the high-temperature exhaust gas leaving the gas turbine can still be used for the operation of the steam generator.

[0032] In principle, it is also possible to use an external energy source to operate the heater. However, instead of using an external energy source for the heater of the ammonia cracker, advantageously, the decomposed hydrogen is used as fuel for the heater.

[0033] By burning the hydrogen decomposed by the ammonia cracker in the heater, the efficiency of the gas turbine device can be further improved.

[0034] As is clear, in the startup process, it is necessary to externally supply hydrogen to obtain additional heat in the ammonia cracker. However, in principle, during the normal operation of the gas turbine device, the hydrogen required for the operation of the heater is preferably branched from the flow of hydrogen and nitrogen exiting the fuel outlet of the ammonia cracker.

[0035] As an alternative, it is possible to burn undecomposed ammonia in the heater and / or combustor during the startup of the gas turbine. This causes NOx emissions during the startup process, but may be acceptable for a short period during the startup of the gas turbine.

[0036] In principle, it is possible to install a separate combustion system for burning hydrogen within the ammonia cracker. However, it is advantageous to burn the hydrogen directly within the air channels of the ammonia cracker. This reduces installation work and improves efficiency.

[0037] The ammonia supplied from the ammonia source is expected to be at a lower temperature compared to the temperature required inside the ammonia cracker. On the other hand, the mixture of hydrogen and nitrogen discharged from the ammonia cracker becomes hot due to the heating required for the decomposition process. Here, it is advantageous to reuse the heat contained in this mixture to heat the ammonia supplied to the ammonia cracker.

[0038] The gas turbine system is advantageously equipped with a fuel heat exchanger located in the ammonia cracker. The fuel heat exchanger should have an exchanger ammonia passage and an exchanger fuel passage. The exchanger fuel passage needs to be connected to the cracker fuel outlet in the ammonia cracker at the exchanger fuel inlet. The exchanger ammonia passage needs to be connected to the cracker ammonia inlet of the ammonia cracker on the exchanger ammonia outlet side.

[0039] The ammonia source must be connected to the exchanger ammonia inlet of the exchanger ammonia passage. Meanwhile, the exchanger fuel outlet of the exchanger fuel passage must be connected to at least one combustor. As is obvious, in this preferred embodiment, the fuel flow (first as ammonia, then as a mixture of hydrogen and nitrogen) passes through the fuel heat exchanger twice.

[0040] In particular, when two or more ammonia crackers are present, it is possible to connect a heater to the fuel piping between the cracker fuel outlet of the ammonia cracker and the exchanger fuel inlet to supply a portion of the decomposed ammonia to the preferred heater. Alternatively, the heater can also be connected to the fuel piping between the exchanger fuel outlet and the combustor.

[0041] It is possible to supply ammonia in gaseous form from an ammonia source.

[0042] If the ammonia source supplies ammonia in liquid form, it is preferable to use an additional ammonia vaporizer. The ammonia vaporizer should include a vaporizer fluid passage and a vaporizer ammonia passage, the vaporizer ammonia passage being connected to the ammonia source at the vaporizer ammonia inlet and to the exchanger ammonia inlet of a preferred fuel heat exchanger's exchanger ammonia passage at the vaporizer ammonia outlet.

[0043] The vaporizer fluid passages need to be supplied with a heated medium.

[0044] In combination with a preferred ammonia vaporizer, it is advantageous to use the heat from the exhaust gases exiting the low-pressure expansion turbine to preheat the ammonia. Two different solutions are proposed here.

[0045] In the first embodiment, the vaporizer fluid passage of the ammonia vaporizer is connected to the outlet and inlet sides of, for example, one of the heat exchangers installed in the steam generator.

[0046] In the second embodiment, the ammonia vaporizer is located downstream of the low-pressure expansion turbine, where the vaporization passage is installed as a heat exchanger, and the passage through which the exhaust gas passes becomes the vaporizer fluid passage of the ammonia vaporizer. [Brief explanation of the drawing]

[0047] [Figure 1]Figure 1 schematically shows a first exemplary embodiment of the gas turbine apparatus 01 of the present invention, in which one ammonia cracker 11 is positioned between a high-pressure expansion turbine and a low-pressure expansion turbine. [Figure 2] Figure 2 schematically shows a second exemplary embodiment of the gas turbine apparatus 21 of the present invention, which includes three ammonia crackers 11a, 11b, and 11c.

[0048] [Detailed description of the drawing] The gas turbine apparatus 01 shown in Figure 1 includes a gas turbine comprising a compressor 02, a combustor 03, a high-pressure expansion turbine 04, and a low-pressure expansion turbine 05. Compressed combustion air is normally supplied from the compressor 02 to the combustor 03, and the exhaust gas produced there is supplied from the combustor 03 to the high-pressure expansion turbine 04 to drive the gas turbine rotor. The hot exhaust gas is then further supplied to the low-pressure expansion turbine 05 to drive the generator in normal operation.

[0049] Furthermore, an ammonia cracker 11 is required, and the ammonia cracker 11 is located between the high-pressure expansion turbine 04 and the low-pressure expansion turbine 05. The ammonia cracker 11 has a cracker air channel connected to the outlet side of the high-pressure expansion turbine 04 at the cracker air inlet. As a result, the high-temperature exhaust gas leaving the high-pressure expansion turbine 04 flows into the cracker air channel of the ammonia cracker 11. The low-pressure expansion turbine 05 has its inlet side located at the cracker air outlet of the ammonia cracker 11, and the exhaust gas after passing through the ammonia cracker 11 flows into the low-pressure expansion turbine 05.

[0050] A cracker reaction passage is located within the ammonia cracker 11. The reaction passage receives a supply of gaseous ammonia at the cracker ammonia inlet. A mixture of hydrogen and nitrogen is supplied from the cracker fuel outlet of the cracker reaction channel. The heat within the cracker reaction channel necessary to enable the decomposition of ammonia is supplied by the hot exhaust gas.

[0051] The cracker ammonia inlet and cracker fuel outlet of the cracker reaction channel are connected to the fuel heat exchanger 12. Therefore, the fuel heat exchanger 12 includes an exchanger ammonia passage and an exchanger fuel passage.

[0052] Ammonia is supplied at the inlet side of the exchanger ammonia passage. By passing through the fuel heat exchanger 12, the ammonia is heated using the heat in the hydrogen and nitrogen mixture passing through the exchanger fuel passage. This enables efficient reuse of the heat required in the ammonia cracker 11.

[0053] Since the fuel outlet of the fuel exchanger fuel passage of the fuel heat exchanger 12 is connected to the combustor 03, the fuel, i.e., a mixture of hydrogen and nitrogen, can be used in the combustion process within the gas turbine.

[0054] To make liquid ammonia usable as an ammonia source 14, an ammonia vaporizer 13 is installed between the ammonia source 14 and the fuel heat exchanger 12. The ammonia changes state from liquid to gas within the ammonia vaporizer 13 through heat transfer from the fluid to the ammonia.

[0055] Figure 2 illustrates an extended gas turbine system 21, which includes a gas turbine with a compressor 02, a combustor 03, a high-pressure expansion turbine 04, and a low-pressure expansion turbine 05, similar to the embodiment described above.

[0056] Here, instead of installing only one ammonia cracker, three ammonia crackers 11a, 11b, and 11c are sequentially positioned between the high-pressure expansion turbine 04 and the low-pressure expansion turbine 05.

[0057] Each of the ammonia crackers 11a, 11b, and 11c has a sequentially connected cracker air passage. As a result, the high-temperature exhaust gas leaving the high-pressure expansion turbine 04 first flows into the cracker air passage of the first ammonia cracker 11a, then through the cracker air passage of the second ammonia cracker 11b, and then through the third ammonia cracker 11c. The low-pressure expansion turbine 05 has its inlet side positioned at the cracker air outlet of the last ammonia cracker 11c, and the exhaust gas after passing through the ammonia crackers 11 flows into the low-pressure expansion turbine 05.

[0058] Here again, the heat contained in the heated hydrogen and nitrogen mixture leaving the ammonia crackers 11a, 11b, and 11c is intended to be reused using the fuel heat exchanger 12. The flow through the fuel heat exchanger is the same as in the previous embodiment.

[0059] A portion of the generated hydrogen is diverted and supplied to heaters 15 in ammonia crackers 11b and 11c to reach the temperature required for the decomposition process.

[0060] Heaters 15 are located inside the second and third ammonia crackers 11b and 11c. The heat in the cracker reaction passage that enables the decomposition of ammonia is supplied partly by the exhaust gas and partly by the heaters 15.

[0061] By using one or more ammonia crackers 11a, 11b, and 11c, it is possible to decompose more ammonia than is required for combustion in the combustor 03. This allows hydrogen to be supplied to external equipment. In this example, a hydrogen storage device 24 is shown.

[0062] To further improve efficiency and waste heat reuse, an ammonia vaporizer 13 is positioned within the fuel flow path. Liquid ammonia is supplied from an ammonia source 14 to the vaporizer ammonia passage of the ammonia vaporizer 13, and gaseous ammonia is supplied from the vaporizer ammonia passage to the exchanger ammonia passage of the fuel heat exchanger 12.

[0063] In this embodiment, a portion of the hydrogen and nitrogen mixture flows from the fuel exchanger passage of the fuel heat exchanger 12 through the vaporizer fluid passage of the ammonia vaporizer 13, and is then stored in the hydrogen storage device 24.

[0064] It is also clear that it is possible to direct all the fuel from the fuel heat exchanger 12 to the ammonia vaporizer 13 before branching off to the fuel piping for the combustor 03, the connection to the heater 15, and the connection to the storage device 24.

Claims

1. A gas turbine device (01, 21), The gas turbine comprises a compressor (02), a combustor (03), a high-pressure expansion turbine (04), and a low-pressure expansion turbine (05). During operation of the gas turbine, combustion air is compressed in the compressor (02), at least a portion of the combustion air is supplied from the outlet of the compressor (02) to the combustor (03), exhaust gas is supplied from the combustor (03) to the high-pressure expansion turbine (04) during operation of the gas turbine, and further, the exhaust gas is supplied to the low-pressure expansion turbine (05). The present invention has at least one ammonia cracker (11, 11a, 11b, 11c), the ammonia cracker having a cracker air channel extending from a cracker air inlet to a cracker air outlet and a cracker reaction channel extending from a cracker ammonia inlet to a cracker fuel outlet. It is characterized by the following: When the gas turbine device (01) is in use, the cracker ammonia inlet is intentionally connected to the ammonia supply source (14). The fuel piping connects the cracker fuel outlet and the combustor (03). The ammonia crackers (11, 11a, 11b, 11c) are positioned between the high-pressure expansion turbine (04) and the low-pressure expansion turbine (05), and the exhaust gas passes through the cracker air channels when the gas turbine is in operation. A gas turbine apparatus characterized by the following features.

2. A gas turbine apparatus (21) according to claim 1, At least two ammonia crackers (11a, 11b, 11c) are sequentially arranged between the high-pressure expansion turbine (04) and the low-pressure expansion turbine (05). A gas turbine apparatus characterized by the following features.

3. A gas turbine apparatus (21) according to claim 2, At least one of the ammonia crackers (11b, 11c) is equipped with a heater (15). A gas turbine apparatus characterized by the following features.

4. A gas turbine apparatus (21) according to claim 2, The heater (15) is capable of burning hydrogen in the air channel. A gas turbine apparatus characterized by the following features.

5. A gas turbine apparatus (01, 21) according to any one of claims 1 to 4, further comprising, The system includes a fuel heat exchanger (12) having an exchanger fuel passage and an exchanger ammonia passage. The ammonia exchange passage is connected to the ammonia supply source (14) at the ammonia exchange inlet and to the cracker ammonia inlet at the ammonia exchange outlet. The exchanger fuel passage is connected to the cracker fuel outlet at the exchanger fuel inlet and to the combustor (03) at the exchanger fuel outlet. A gas turbine apparatus characterized by the following features.

6. The gas turbine apparatus (01, 21) according to claim 5, further, The ammonia vaporizer (13) includes a vaporizer fluid passage and a vaporizer ammonia passage, The vaporizer ammonia passage is connected to the ammonia supply source (14) at the vaporizer ammonia inlet and connected to the exchanger ammonia inlet of the ammonia passage at the vaporizer ammonia outlet. A gas turbine apparatus characterized by the following features.

7. A method for operating a gas turbine system (01, 21), The gas turbine apparatus (01, 21) according to any one of claims 1 to 6, At least a portion of the compressed air and the gaseous fuel are supplied to the combustor (03) and burned, and the exhaust gas is supplied from the combustor (03) to the high-pressure expansion turbine (04). The exhaust gas is supplied from the high-pressure expansion turbine (04) to at least one ammonia cracker (11, 11a, 11b, 11c), Ammonia is supplied to the ammonia inlet of the ammonia cracker (11, 11a, 11b, 11c), decomposed in the cracker reaction channel, and a mixture of hydrogen and nitrogen is supplied as a gaseous fuel from the cracker fuel outlet to the combustor (03). The exhaust gas is supplied from the ammonia crackers (11, 11a, 11b, 11c) to the low-pressure expansion turbine (05). A method characterized by the following:

8. The method according to claim 7, A method characterized in that additional heat is introduced into the ammonia crackers (11b, 11c) by a heater (15).

9. The method according to claim 7 or 8, Ammonia is supplied from the ammonia source (14) to the fuel heat exchanger (12), passes through the ammonia passage of the exchanger, and is led from the fuel heat exchanger to the ammonia crackers (11, 11a, 11b, 11c). The decomposed gaseous fuel is guided from the cracker fuel outlet to the fuel heat exchanger (12), passes through the exchanger fuel passage, and is then guided from the fuel heat exchanger (12) to the combustor (03). A method characterized by the following:

10. A method according to any one of claims 7 to 9, A portion of the decomposed gaseous fuel is extracted from the fuel piping and supplied to the heater (15), and burned in the ammonia crackers (11b, 11c). A method characterized by the following:

11. A method according to any one of claims 7 to 10, A method characterized in that a portion of the decomposed gaseous fuel is supplied to the outside of the gas turbine device (01).

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