JP7713864B2 - Gas Turbine Systems - Google Patents

Description

The present invention relates to a gas turbine system that uses hydrogen obtained by decomposing ammonia as fuel.

Fossil fuels, which inevitably emit carbon dioxide when burned, are used as fuel for gas turbine systems. However, in recent years, global warming caused by carbon dioxide released into the atmosphere has become a problem, and in response to this, there is an urgent need to reduce the release of carbon dioxide into the atmosphere. As a result, gas turbine systems that use hydrogen as fuel, which does not emit carbon dioxide when burned, have attracted attention.

However, hydrogen has a low energy density and is inefficient to transport and store compared to fossil fuels. For this reason, progress is being made in the development of a gas turbine system that uses ammonia as an energy carrier to transport hydrogen, extracts hydrogen by decomposing the ammonia, and uses this hydrogen as fuel.

For example, Patent Document 1 discloses a gas turbine plant that combines an ammonia decomposition device that thermally decomposes ammonia to produce hydrogen, with a gas turbine.

In this gas turbine plant, ammonia is thermally decomposed in an ammonia decomposition unit using steam heated by heat generated in the gas turbine, producing a decomposition gas containing hydrogen, nitrogen, and residual ammonia. The residual ammonia in the decomposition gas is then removed by an ammonia removal unit, and the gas after the residual ammonia removal is used as fuel gas for the gas turbine. In addition, the residual ammonia removed by the ammonia removal unit is supplied again to the ammonia decomposition unit for reuse.

JP 2020-147481 A

In the gas turbine plant described in Patent Document 1, ammonia decomposition in the ammonia decomposition unit is performed at high pressure (approximately 3 to 5 MPa) from the perspective of system efficiency, so ammonia decomposition must be performed at high temperature (approximately 500 to 600°C). In such high temperature ranges, the ammonia and the residual ammonia in the decomposition gas cause nitriding of the metal materials used in the ammonia decomposition unit and the like. As a result, the gas turbine plant has the problem that its durability is easily reduced. In addition, since ammonia decomposition must be performed at high temperature, a larger amount of steam is required, which also causes the problem of reduced energy efficiency of the system.

Furthermore, in the above gas turbine plant, the remaining ammonia is removed and reused, but the entire decomposition gas from the ammonia decomposition unit must be treated in an ammonia removal unit. This requires a large-capacity ammonia removal unit, and the energy required for recovery tends to increase.

In addition, there is a limit to the amount of residual ammonia that can be removed using an ammonia removal device. As a result, the gas after the residual ammonia removal still contains approximately 0.03 mol% ammonia. If this gas is supplied to a gas turbine, a large amount of NOx is generated, making it necessary to take measures to reduce this amount.

The present invention has been developed in consideration of the above-mentioned circumstances, and aims to provide a gas turbine system that is durable, energy efficient, and has reduced NOx emissions.

The gas turbine system according to the present invention for achieving the above object has the following characteristic configuration:
an ammonia decomposition apparatus including a catalyst packed section filled with an ammonia decomposition catalyst, a membrane separation section including a hydrogen separation membrane capable of separating hydrogen from a decomposition gas generated by ammonia decomposition, a recovery section for recovering the residual ammonia from a hydrogen separation treated gas containing nitrogen and residual ammonia, and an ammonia recycle path for supplying the residual ammonia recovered in the recovery section to the catalyst packed section;
an ammonia supplying means for supplying ammonia to the catalyst packed section;
a gas turbine unit including a compressor that compresses air to generate compressed air, a combustor to which hydrogen separated in the membrane separation unit is supplied through a hydrogen supply passage and which burns the supplied hydrogen in the compressed air to generate combustion gas, and a gas turbine that is driven by the combustion gas;
and an exhaust heat recovery means for recovering heat generated in the gas turbine unit and heating a heat medium,
The heat medium heated by the exhaust heat recovery means is supplied to the ammonia decomposition device ,
The nitrogen from which the remaining ammonia has been recovered in the recovery section is supplied as a cooling gas to the combustor and the gas turbine through a first nitrogen flow passage .

According to the above-mentioned characteristic configuration, in the membrane separation section, it is possible to selectively separate hydrogen from the cracked gas while decomposing ammonia by utilizing the heat generated in the gas turbine unit.
That is, the membrane separation section functions as a so-called membrane reactor, in which the decomposition reaction of ammonia and the separation of hydrogen proceed in parallel. Therefore, compared to the conventional case of decomposing ammonia without using a membrane reactor, the decomposition temperature can be lowered while maintaining a high conversion rate even under high pressure. Therefore, nitridation of metal materials used in ammonia decomposition devices and the like can be suppressed, and durability can be improved. Furthermore, according to the above characteristic configuration, since the decomposition of ammonia can be performed at a lower temperature than in the past, the amount of heat medium required to heat the ammonia decomposition device can be reduced, and the energy efficiency of the system can be improved.
Furthermore, according to the above characteristic configuration, hydrogen can be selectively separated from the cracked gas, and high-purity hydrogen and hydrogen-separated gas containing nitrogen and remaining ammonia can be obtained separately. Therefore, when recovering the remaining ammonia, it is sufficient to supply the hydrogen-separated gas to the recovery section, and since the amount of gas to be treated is reduced, the volume of the recovery section can be reduced, and the energy required for recovery can be reduced. In addition, since high-purity hydrogen can be supplied as fuel for the gas turbine unit, thermal efficiency is also improved. Furthermore, since there is no ammonia remaining in the fuel supplied to the gas turbine unit, or even if there is, the amount is extremely small compared to the conventional method, NOx emissions can also be reduced.
As described above, according to the above-mentioned characteristic configuration, a gas turbine system that is excellent in durability and energy efficiency and also reduces NOx emissions can be realized.

Furthermore, according to the above-mentioned characteristic configuration, the nitrogen from which the remaining ammonia has been recovered in the recovery section can be used to cool high-temperature components of the gas turbine unit, such as the gas turbine and combustor, etc. Therefore, it is possible to operate at high temperatures without using expensive heat-resistant materials for the gas turbine and combustor, thereby improving thermal efficiency and reducing costs.

The gas turbine system according to the present invention for achieving the above object has the following characteristic configuration:
an ammonia decomposition apparatus including a catalyst packed section filled with an ammonia decomposition catalyst, a membrane separation section including a hydrogen separation membrane capable of separating hydrogen from a decomposition gas generated by ammonia decomposition, a recovery section for recovering the residual ammonia from a hydrogen separation treated gas containing nitrogen and residual ammonia, and an ammonia recycle path for supplying the residual ammonia recovered in the recovery section to the catalyst packed section;
an ammonia supplying means for supplying ammonia to the catalyst packed section;
a gas turbine unit including a compressor that compresses air to generate compressed air, a combustor to which hydrogen separated in the membrane separation unit is supplied through a hydrogen supply passage and which burns the supplied hydrogen in the compressed air to generate combustion gas, and a gas turbine that is driven by the combustion gas;
and an exhaust heat recovery means for recovering heat generated in the gas turbine unit and heating a heat medium,
The heat medium heated by the exhaust heat recovery means is supplied to the ammonia decomposition device,
a second nitrogen flow passage through which the nitrogen from which the residual ammonia has been recovered in the recovery section flows is connected to the hydrogen supply passage;
The present invention is characterized in that a mixed gas of the hydrogen and the nitrogen can be supplied to the combustor.

According to the above-described characteristic configuration, in the membrane separation section, it is possible to selectively separate hydrogen from the cracked gas while decomposing ammonia by utilizing the heat generated in the gas turbine unit.
That is, the membrane separation section functions as a so-called membrane reactor, in which the decomposition reaction of ammonia and the separation of hydrogen proceed in parallel. Therefore, compared to the conventional case of decomposing ammonia without using a membrane reactor, the decomposition temperature can be lowered while maintaining a high conversion rate even under high pressure. Therefore, nitridation of metal materials used in ammonia decomposition devices and the like can be suppressed, and durability can be improved. Furthermore, according to the above characteristic configuration, since the decomposition of ammonia can be performed at a lower temperature than in the past, the amount of heat medium required to heat the ammonia decomposition device can be reduced, and the energy efficiency of the system can be improved.
Furthermore, according to the above characteristic configuration, hydrogen can be selectively separated from the cracked gas, and high-purity hydrogen and hydrogen-separated gas containing nitrogen and remaining ammonia can be obtained separately. Therefore, when recovering the remaining ammonia, it is sufficient to supply the hydrogen-separated gas to the recovery section, and since the amount of gas to be treated is reduced, the volume of the recovery section can be reduced, and the energy required for recovery can be reduced. In addition, since high-purity hydrogen can be supplied as fuel for the gas turbine unit, thermal efficiency is also improved. Furthermore, since there is no ammonia remaining in the fuel supplied to the gas turbine unit, or even if there is, the amount is extremely small compared to the conventional method, NOx emissions can also be reduced.
As described above, according to the above-mentioned characteristic configuration, a gas turbine system that is excellent in durability and energy efficiency and also reduces NOx emissions can be realized.

Furthermore, for example, when only hydrogen is supplied as fuel, if it becomes necessary to throttle the amount of fuel supplied to the gas turbine unit, backfire may occur if the amount of fuel supplied falls below a certain level, resulting in unstable combustion. According to the above-described characteristic configuration, a mixed gas of hydrogen and nitrogen can be supplied to the gas turbine unit, and therefore, when it becomes necessary to throttle the amount of fuel supplied, a gas in which an optimal amount of nitrogen is mixed with hydrogen can be supplied, thereby ensuring stable combustion.

A further characteristic configuration of the gas turbine system according to the present invention is
a second nitrogen flow passage through which the nitrogen from which the residual ammonia has been recovered in the recovery section flows is connected to the hydrogen supply passage;
The present invention is characterized in that a mixed gas of the hydrogen and the nitrogen can be supplied to the combustor.

For example, when only hydrogen is supplied as fuel, if it becomes necessary to reduce the amount of fuel supplied to the gas turbine unit, backfiring may occur if the amount of supply falls below a certain level, resulting in unstable combustion. With the above characteristic configuration, a mixed gas of hydrogen and nitrogen can be supplied to the gas turbine unit, so that when it becomes necessary to reduce the amount of fuel supplied, an optimal amount of nitrogen mixed with hydrogen can be supplied, resulting in stable combustion.

A further characteristic configuration of the gas turbine system according to the present invention is
The present invention is characterized in that a control unit is provided for adjusting the mixture ratio of the hydrogen and the nitrogen in the mixed gas in response to load fluctuations.

According to the above characteristic configuration, the mixture ratio of the mixed gas can be adjusted according to the load fluctuation. In other words, the mixture ratio can be adjusted so that the optimal amount of nitrogen is mixed with hydrogen according to the load, and the mixed gas with the adjusted mixture ratio can be supplied to the gas turbine unit as fuel gas. Therefore, for example, in the case of a high load where a large amount of hydrogen is required, the mixture ratio (hydrogen:nitrogen) can be adjusted to 100:0, and only hydrogen can be supplied to the gas turbine unit as fuel, thereby obtaining high thermal efficiency. On the other hand, in the case of a low load (low load), the occurrence of backfire can be suppressed and a stable combustion state can be obtained. In other words, according to the above characteristic configuration, hydrogen and nitrogen can be mixed to obtain an appropriate mixture ratio according to the load fluctuation, and a stable combustion state can be maintained at all times even if the load fluctuates while obtaining high thermal efficiency. As a result, for example, when the gas turbine system is used as a gas turbine combined cycle power generation system, a stable supply of power is possible.

A further characteristic configuration of the gas turbine system according to the present invention is
The ammonia supply means supplies the ammonia at a supply pressure higher than atmospheric pressure.

The above characteristic configuration can promote the permeation of hydrogen generated in the catalyst-filled section, thereby accelerating ammonia decomposition.

A further characteristic configuration of the gas turbine system according to the present invention is
The present invention is characterized in that it comprises a pressure reducing means for reducing the pressure on the hydrogen permeation side of the membrane separation section from the downstream side in the hydrogen flow direction so that the pressure on the hydrogen permeation side of the membrane separation section is lower than that on the catalyst-packed section side.

The above characteristic configuration can further promote the permeation of hydrogen and the decomposition of ammonia generated in the catalyst-filled section.

A further characteristic configuration of the gas turbine system according to the present invention is
The present invention is characterized in that it comprises a sweep gas supplying means for supplying a sweep gas to the hydrogen permeation side of the membrane separation section.

The above characteristic configuration can further promote the permeation of hydrogen and the decomposition of ammonia generated in the catalyst-filled section.

1 is a diagram showing a schematic configuration of a gas turbine combined cycle power generation system according to an embodiment. FIG. 2 is a diagram showing an operating state of a gas turbine combined cycle power generation system at high load. FIG. 2 is a diagram showing an operating state of a gas turbine combined cycle power generation system at low load. FIG. 13 is a view showing a membrane separation unit according to another embodiment. FIG. 13 is a view showing a membrane separation unit according to another embodiment.

A gas turbine system according to one embodiment of the present invention will be described below with reference to the drawings. Note that the following description will be given by taking as an example a case in which the gas turbine system is a gas turbine combined cycle power generation system (GTCC).

1 is a diagram showing a schematic configuration of a gas turbine combined cycle power generation system 1 according to one embodiment. As shown in FIG. 1, the gas turbine combined cycle power generation system 1 includes an ammonia decomposition device 2 that decomposes ammonia to generate hydrogen, an ammonia supply unit 10 (ammonia supply means) that supplies ammonia to the ammonia decomposition device 2, a gas turbine unit 15 that generates combustion gas using hydrogen as fuel and rotates a gas turbine 18 using the combustion gas, and a heat recovery boiler unit 20 (exhaust heat recovery means) that recovers heat generated in the gas turbine unit 15 and heats water as a heat medium. The gas turbine combined cycle power generation system 1 also includes a control device 25 (control unit) that controls the operation of each unit, a steam turbine unit 21 in which a steam turbine 22 is rotated by steam generated in the heat recovery boiler unit 20, a first generator 19, a second generator 23, and the like that generate electricity using the rotational force.

The ammonia decomposition device 2 is a device that decomposes ammonia to produce hydrogen, and has a membrane separation section 3, an ammonia recovery section 6 (recovery section), and an ammonia recycle line L6.

The membrane separation section 3 is configured to function as a so-called membrane reactor, and is composed of a catalyst-filled section 4 filled with an ammonia decomposition catalyst C, and a hydrogen separation membrane 3b capable of separating hydrogen generated by ammonia decomposition. In this embodiment, the membrane separation section 3 has a double-tube structure consisting of a metal tube 3a as an outer tube and a cylindrical hydrogen separation membrane 3b as an inner tube, and an ammonia decomposition catalyst C is filled between the metal tube 3a and the hydrogen separation membrane 3b to form the catalyst-filled section 4. Examples of the ammonia decomposition catalyst C include Fe-based, Co-based, Ni-based, and Ru-based catalysts. Examples of the hydrogen separation membrane 3b include a silica membrane, a zeolite membrane, a palladium membrane, a carbon membrane, and a MOF (metal-organic framework) membrane.

The membrane separation section 3 is supplied with steam from the heat recovery boiler unit 20 (described later) through the first steam supply passage L10, and the membrane separation section 3 is heated by this steam, and the ammonia decomposition catalyst C in the catalyst packing section 4 is heated to a predetermined temperature (e.g., 300 to 450°C). In addition, ammonia is supplied to the catalyst packing section 4 of the membrane separation section 3 at a predetermined supply pressure through the ammonia supply passage L1, one end of which is connected to the ammonia supply pump 12 (described later).

Here, in the membrane separation section 3, the ammonia decomposition catalyst C is heated to a predetermined temperature, and ammonia is pumped into the catalyst packing section 4, where the ammonia is decomposed by the action of the ammonia decomposition catalyst C to generate decomposition gas containing hydrogen and nitrogen. Of the decomposition gas, hydrogen permeates the cylindrical hydrogen separation membrane 3b and is selectively separated to the inside (hydrogen permeation side). That is, in the membrane separation section 3, the decomposition of ammonia and the separation of hydrogen proceed in parallel.

Therefore, by providing the membrane separation section 3, as described above, it is possible to proceed with the decomposition reaction of ammonia at a temperature of about 300 to 450°C while maintaining a high conversion rate even under relatively high pressure conditions in which ammonia is supplied at a specified supply pressure. This makes it possible to suppress nitridation of the metal material used in the ammonia decomposition device 2, resulting in a highly durable ammonia decomposition device 2. In addition, because ammonia decomposition can be performed at a low temperature, the amount of steam supplied through the first steam supply path L10 can be reduced, improving the energy efficiency of the entire system.

High-purity hydrogen (e.g., 95% to 99.999%) separated from the cracked gas is sent to the combustor 17 of the gas turbine unit 15 through the hydrogen supply passage L2 connected to the hydrogen permeation side of the cylindrical hydrogen separation membrane 3b. The gas (hydrogen-separated gas) from which hydrogen has been separated and which contains nitrogen and unreacted ammonia (residual ammonia) is sent to the ammonia recovery section 6 through the treated gas flow passage L3 connected to the downstream side of the ammonia flow direction in the catalyst charging section 4. In this embodiment, a first flow meter S1 is provided in the hydrogen supply passage L2, and the measurement results are sent to the control device 25 as appropriate.

As described above, the membrane separation section 3 decomposes ammonia under relatively high pressure conditions, so the energy required to boost the pressure of the hydrogen and nitrogen produced to supply them to the combustor 17, which is supplied with compressed air, is reduced compared to when ammonia is decomposed under low pressure conditions.

The ammonia recovery section 6 is configured to recover the remaining ammonia from the hydrogen separation treated gas containing nitrogen and the remaining ammonia. The method for recovering the remaining ammonia from the hydrogen separation treated gas can be a known method.

The ammonia recovery section 6 of this embodiment is composed of an absorption section 7 that dissolves the remaining ammonia in the hydrogen-separated gas in water and absorbs it, and a separation section 8 that heats ammonia water, which is water in which ammonia has been dissolved, to separate and distill the ammonia from the ammonia water. As described above, in this embodiment, the gas treated in the ammonia recovery section 6 is gas from which hydrogen has been separated, so the volume of the ammonia recovery section 6 is smaller than when treating gas from which hydrogen has not been separated, and the energy required for recovery is reduced.

Specifically, in the ammonia recovery section 6 of this embodiment, the hydrogen separation-treated gas is supplied to the absorption section 7 through the treated gas flow passage L3, and the remaining ammonia is dissolved in low-temperature water to remove the remaining ammonia from the hydrogen separation-treated gas. The nitrogen-based gas from which the remaining ammonia has been removed (for example, the remaining ammonia concentration is about 0.03 mol%) is sent through the first nitrogen supply passage L4 (first nitrogen flow passage) to the combustor 17 and gas turbine 18 of the gas turbine unit 15 described later, or sent through the second nitrogen supply passage L5 (second nitrogen flow passage) described later to the hydrogen supply passage L2. The temperature of the nitrogen-based gas after the removal of the remaining ammonia varies depending on the method of recovering the remaining ammonia, but is about room temperature to 400°C. In addition, in this embodiment, depending on various conditions such as the type of hydrogen separation membrane 3b, the supply pressure of ammonia, and the presence or absence of sweep gas, some of the hydrogen that was not separated in the membrane separation section 3 may be included in the nitrogen-based gas after the removal of the remaining ammonia.

Meanwhile, the water with the remaining ammonia dissolved therein is sent to the separation section 8, where it is heated by steam supplied from the heat recovery boiler unit 20 through the second steam supply line L11. Then, the ammonia is separated and distilled from the heated ammonia water using water steam, and the ammonia is recovered.

In this embodiment, the first nitrogen supply passage L4 is provided with a first flow rate control valve V1 that adjusts the supply flow rate of the gas mainly composed of nitrogen to the combustor 17 and the gas turbine 18. The second nitrogen supply passage L5 is provided with a second flow rate control valve V2 that adjusts the supply flow rate of the gas mainly composed of nitrogen to the hydrogen supply passage L2, and a second flow meter S2 downstream of the second flow rate control valve V2 in the flow direction of the gas mainly composed of nitrogen. The measurement results of the second flow meter S2 are appropriately transmitted to the control device 25.

The ammonia recycle path L6 is configured to supply the remaining ammonia recovered in the ammonia recovery section 6 to the catalyst charging section 4. Specifically, in this embodiment, one end of the ammonia recycle path L6 is connected to the separation section 8 of the ammonia recovery section 6, and the other end is connected to the ammonia supply path L1 between the ammonia supply pump 12 and the catalyst charging section 4.

The ammonia supply unit 10 includes an ammonia tank 11 in which ammonia is stored, an ammonia supply pump 12 installed in an ammonia supply path L1 connecting the ammonia tank 11 and the catalyst-filled unit 4 of the membrane separation unit 3, and a preheater for preheating the ammonia. In this embodiment, the ammonia tank 11 stores ammonia cooled to a temperature below the boiling point and at approximately atmospheric pressure. The ammonia supply unit 10 pressurizes and preheats the ammonia in the ammonia tank 11 and supplies it to the catalyst-filled unit 4 through the ammonia supply path L1 at a predetermined supply pressure (a pressure higher than atmospheric pressure, for example, about 2 to 3 MPa).

The gas turbine unit 15 has a compressor 16, a combustor 17, and a gas turbine 18.

The compressor 16 compresses air to generate compressed air. Specifically, the compressor 16 receives air through the first air supply passage L7, compresses the supplied air to generate compressed air, and sends the compressed air to the combustor 17.

The combustor 17 is supplied with hydrogen separated in the membrane separation section 3 through the hydrogen supply passage L2, and burns the supplied hydrogen in compressed air to generate combustion gas. Specifically, the combustor 17 is supplied with high-purity hydrogen through the hydrogen supply passage L2, one end of which is connected to the hydrogen permeation side of the membrane separation section 3, and is supplied with gas mainly composed of nitrogen after residual ammonia recovery through the hydrogen supply passage L2 via the second nitrogen supply passage L5, one end of which is connected to the ammonia recovery section 6 and the other end of which is connected to the hydrogen supply passage L2. Furthermore, compressed air is supplied to the combustor 17 from the compressor 16 through the second air supply passage L8. The combustor 17 then burns a mixture of hydrogen, a gas mainly composed of nitrogen, and compressed air, and sends the generated combustion gas to the gas turbine 18 through the combustion gas supply passage L9. In this way, in this embodiment, high-purity hydrogen is supplied to the combustor 17, improving thermal efficiency, and since no ammonia remains in the supplied fuel, or even if it does, it is extremely small, NOx emissions are also suppressed.

The gas turbine 18 is driven by the combustion gas. Specifically, the gas turbine 18 is rotated and driven by the combustion gas sent out from the combustor 17, and the rotational force is transmitted to the compressor 16 and the first generator 19. In addition, the combustion gas used to rotate the gas turbine 18 is sent out as exhaust gas to the heat recovery boiler unit 20.

In this embodiment, the combustor 17 and the gas turbine 18 are configured to be supplied with a gas mainly composed of nitrogen as a cooling gas through the first nitrogen supply passage L4. In this manner, in this embodiment, the combustor 17 and the gas turbine 18 are cooled using a gas mainly composed of nitrogen as a cooling gas, so that the combustor 17 and the gas turbine 18 can be operated at high temperatures without using expensive heat-resistant materials, improving thermal efficiency and reducing costs. The temperature of the gas mainly composed of nitrogen as a cooling gas is from room temperature to about 400°C as described above. The gas mainly composed of nitrogen used to cool the combustor 17 and the gas turbine 18 may be introduced into the combustor 17 and the gas turbine 18, or may be introduced into the heat recovery boiler unit 20 to recover the exhaust heat and then exhausted.

Various modes can be used to cool the combustor 17 with a gas mainly made of nitrogen, but an example is a mode in which a gas mainly made of nitrogen flows along the outer wall surface of the combustor 17 and cools the combustor 17 by removing heat from the outer wall surface. Also, various modes can be used to cool the gas turbine 18, but an example is a mode in which a gas mainly made of nitrogen flows inside the turbine blades and cools them from the inside.

The heat recovery boiler unit 20 is configured to recover heat from the exhaust gas by utilizing the heat of the exhaust gas discharged from the gas turbine unit 15 to vaporize water and generate steam. Specifically, in this embodiment, the heat recovery boiler unit 20 heats and vaporizes water in multiple drums (not shown) using the heat of the exhaust gas from the gas turbine 18 to generate steam. This steam is then sent to the membrane separation section 3 of the ammonia decomposition device 2 through the first steam supply line L10, and is also sent to the separation section 8 of the ammonia recovery section 6 through the second steam supply line L11. Furthermore, the generated steam is sent to the steam turbine 22 of the steam turbine unit 21 through the third steam supply line L12.

The steam turbine unit 21 has a steam turbine 22 and a condenser. The steam turbine 22 is driven to rotate by steam sent from the heat recovery boiler unit 20, and the rotational force is transmitted to the second generator 23.

The first generator 19 is driven by the gas turbine 18 to generate electricity, and the second generator 23 is driven by the steam turbine 22 to generate electricity.

The control device 25 controls the operation of each part as described above. In this embodiment, the control device 25 is configured to adjust the mixture ratio of the mixed gas of hydrogen and nitrogen supplied to the combustor 17 in response to changes in the amount of power generation required for the gas turbine combined cycle power generation system 1 (in other words, in response to load fluctuations). The amount of power generation required for the gas turbine combined cycle power generation system 1 depends on the amount of power generation using variable renewable energy such as solar power generation and wind power generation, and when the amount of power generation using variable renewable energy is low, the amount of power generation required for the gas turbine combined cycle power generation system 1 becomes high (i.e., the load becomes high). Information regarding the load of the gas turbine combined cycle power generation system 1 may be received by the control device 25 via wired or wireless communication, or may be input to the control device 25 by a facility manager or the like.

When a large amount of power generation is required (high load), it is preferable to supply only hydrogen as fuel to the gas turbine unit 15 to obtain high power generation efficiency (thermal efficiency). Therefore, as shown in FIG. 2, in the case of high load, the control device 25 of this embodiment controls the operation of the second flow control valve V2 provided in the second nitrogen supply passage L5 to close it, and adjusts the mixture ratio of the gas supplied to the combustor 17 (gas flowing through the hydrogen supply passage L2 (high purity hydrogen): gas flowing through the second nitrogen supply passage L5 (gas mainly composed of nitrogen)) to 100:0. As a result, only the gas flowing through the hydrogen supply passage L2 (high purity hydrogen) is supplied to the combustor 17.

On the other hand, when the load is not so high, if only high-purity hydrogen is supplied as fuel, there is a risk that the supply amount will fall below a certain level, causing backfire and making it impossible to obtain stable combustion. Therefore, the mixture ratio of hydrogen and nitrogen supplied to the combustor 17 is adjusted so that the required amount of hydrogen is supplied according to the level of load, and the amount of gas supplied to the combustor 17 is an amount that does not cause backfire. Specifically, the control device 25 adjusts the mixture ratio so that the smaller the load, the greater the amount of nitrogen mixed with hydrogen supplied to the combustor 17.

In this embodiment, the control device 25 adjusts the amount of gas (high-purity hydrogen) flowing through the hydrogen supply line L2 and the amount of gas (mainly nitrogen gas) flowing through the second nitrogen supply line L5 and supplied to the hydrogen supply line L2 based on the measurement results of the first flow meter S1 and the second flow meter S2 so that the mixture ratio of the mixed gas becomes a target value according to the load. That is, as shown in FIG. 3, the control device 25 controls the operation of the ammonia supply pump 12 to adjust the supply amount of high-purity hydrogen according to the load fluctuation, and adjusts the opening degree of the second flow control valve V2 to adjust the supply amount of gas mainly composed of nitrogen to the hydrogen supply line L2, and adjusts the flow rate of each gas so that the required amount of hydrogen is supplied and the mixture ratio becomes a target value. As a result, hydrogen and nitrogen are mixed to obtain an appropriate mixture ratio according to the load fluctuation, so that a stable combustion state can be maintained at all times even if the load fluctuates while obtaining high thermal efficiency, and a stable supply of power is possible.

As mentioned above, a certain amount of hydrogen may be contained in the nitrogen-based gas. Therefore, when adjusting the flow rate of each gas (high-purity hydrogen and nitrogen-based gas) so that the required amount of hydrogen is supplied and the mixture ratio becomes the target value, if the amount of hydrogen remaining in the nitrogen-based gas is not negligible, the flow rate of each gas may be adjusted taking into account the amount of remaining hydrogen. On the other hand, if the amount of remaining hydrogen is extremely small, the flow rate of each gas may be adjusted while ignoring the amount of remaining hydrogen. The amount of remaining hydrogen may be obtained, for example, by analyzing the components of the gas flowing through the first nitrogen supply path L4.

In addition, in the ammonia decomposition device 2, hydrogen:nitrogen is generated at a ratio of 3:1. Therefore, the control device 25 adjusts the mixture ratio of the gas (nitrogen-based gas) flowing through the second nitrogen supply line L5 to the gas (high-purity hydrogen) flowing through the hydrogen supply line L2 so that the mixture amount is a maximum of one-third. Note that the more the mixture amount of nitrogen-based gas to high-purity hydrogen increases, the less the amount of nitrogen-based gas that can be used to cool the combustor 17 and the gas turbine 18 decreases. However, for example, a portion of the nitrogen-based gas generated during high-load operation can be stored in a tank or the like, and when the load decreases, the nitrogen-based gas stored in the tank can be mixed with high-purity hydrogen or used to cool the combustor 17 and the gas turbine 18.

In the gas turbine combined cycle power generation system 1 having the above configuration, ammonia is decomposed into hydrogen and nitrogen in the membrane separation section 3, and the hydrogen produced is selectively separated to supply high-purity hydrogen to the combustor 17, where a mixture of high-purity hydrogen and compressed air is burned as fuel. The generated combustion gas is then sent to the gas turbine 18, which rotates and drives the gas turbine 18, and the rotational force drives the first generator 19 to generate electricity.

In addition, in this gas turbine combined cycle power generation system 1, the combustion gas used to drive the gas turbine 18 is sent as exhaust gas to the heat recovery boiler unit 20, where the heat contained in the exhaust gas is used to produce steam. This steam is then sent to the steam turbine unit 21, which drives the steam turbine 22, and the rotational force of this drive the second generator 23 to generate electricity.

In addition, in this gas turbine combined cycle power generation system 1, the mixture ratio of the hydrogen and nitrogen gas mixture supplied to the combustor 17 is adjusted in response to fluctuations in the required amount of power generation (load fluctuations) so that a necessary and sufficient amount of hydrogen is supplied without causing large fluctuations in the amount of gas supplied to the combustor 17.

[Another embodiment]
[1] In the above embodiment, the combustor 17 and the gas turbine 18 are cooled using the gas mainly containing nitrogen from which the remaining ammonia has been recovered in the ammonia recovery section 6, but the present invention is not limited to this. For example, either one of the combustor 17 and the gas turbine 18 may be cooled with a gas mainly containing nitrogen, or neither the combustor 17 nor the gas turbine 18 may be cooled with a gas mainly containing nitrogen.

[2] In the above embodiment, nitrogen can be mixed with the hydrogen supplied to the combustor 17, but this is not limited thereto, and it may be possible to supply only hydrogen to the combustor 17.

[3] In the above embodiment, the mixture ratio of hydrogen and nitrogen in the mixed gas is adjusted in response to load fluctuations, but this is not limited to the above, and the mixture ratio may not be adjusted.

[4] In the above embodiment, the ammonia supply unit 10 supplies ammonia at a supply pressure higher than atmospheric pressure. However, the present invention is not limited to this. Any configuration may be used as long as a pressure difference occurs between the catalyst filling unit 4 and the hydrogen permeation side.
For example, as shown in Fig. 4, a vacuum pump 30 (pressure reducing means) for reducing the pressure of the hydrogen permeation side of the membrane separation section 3 may be provided downstream of the hydrogen flow direction in the hydrogen supply passage L2, and the hydrogen permeation side may be reduced in pressure by the vacuum pump 30 so that the pressure on the hydrogen permeation side is lower than that on the catalyst packed section side. In this case, a booster 31 is provided downstream of the vacuum pump 30 in the hydrogen supply passage L2, making it possible to supply hydrogen to the combustor 17 at a predetermined supply pressure. In this case, the supply pressure of ammonia to the catalyst packed section 4 may be higher than atmospheric pressure or may be lower than atmospheric pressure.
5, a sweep gas supply section 35 (sweep gas supply means) for supplying air as a sweep gas through a sweep gas supply passage L13 may be provided on the hydrogen permeation side of the membrane separation section 3. Even in this case, the supply pressure of ammonia to the catalyst packed section 4 may be higher than atmospheric pressure or may be lower than atmospheric pressure.

[5] In the above embodiment, the gas turbine system is a gas turbine combined cycle power generation system, but this is not limited thereto, and the gas turbine system according to the present invention may be adopted in a gas turbine system for power generation or a gas turbine system for aircraft.

The configurations disclosed in the above embodiment (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided no contradictions arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. Appropriate modifications can be made without departing from the scope of the present invention.

1: Gas turbine combined cycle power generation system 2: Ammonia decomposition device 3: Membrane separation section 3b: Hydrogen separation membrane 4: Catalyst filling section 6: Ammonia recovery section (recovery section)
10: Ammonia supply section (ammonia supply means)
15: Gas turbine unit 16: Compressor
17: Combustor 18: Gas turbine 20: Exhaust heat recovery boiler unit (exhaust heat recovery means)
25: Control device (control unit)
30: Vacuum pump (pressure reducing means)
35: Sweep gas supply unit (sweep gas supply means)
C: ammonia decomposition catalyst L2: hydrogen supply channel L4: first nitrogen supply channel (first nitrogen flow channel)
L5: Second nitrogen supply channel (second nitrogen flow channel)
L6: Ammonia recycle path

Claims (7)

an ammonia decomposition apparatus including a catalyst packed section filled with an ammonia decomposition catalyst, a membrane separation section including a hydrogen separation membrane capable of separating hydrogen from a decomposition gas generated by ammonia decomposition, a recovery section for recovering the residual ammonia from a hydrogen separation treated gas containing nitrogen and residual ammonia, and an ammonia recycle path for supplying the residual ammonia recovered in the recovery section to the catalyst packed section;
an ammonia supplying means for supplying ammonia to the catalyst packed section;
a gas turbine unit including a compressor that compresses air to generate compressed air, a combustor to which hydrogen separated in the membrane separation unit is supplied through a hydrogen supply passage and which burns the supplied hydrogen in the compressed air to generate combustion gas, and a gas turbine that is driven by the combustion gas;
and an exhaust heat recovery means for recovering heat generated in the gas turbine unit and heating a heat medium,
The heat medium heated by the exhaust heat recovery means is supplied to the ammonia decomposition device ,
the nitrogen from which the remaining ammonia has been recovered in the recovery section is supplied as a cooling gas to the combustor and the gas turbine through a first nitrogen passage . an ammonia decomposition apparatus including a catalyst packed section filled with an ammonia decomposition catalyst, a membrane separation section including a hydrogen separation membrane capable of separating hydrogen from a decomposition gas generated by ammonia decomposition, a recovery section for recovering the residual ammonia from a hydrogen separation treated gas containing nitrogen and residual ammonia, and an ammonia recycle path for supplying the residual ammonia recovered in the recovery section to the catalyst packed section;
an ammonia supplying means for supplying ammonia to the catalyst packed section;
a gas turbine unit including a compressor that compresses air to generate compressed air, a combustor to which hydrogen separated in the membrane separation unit is supplied through a hydrogen supply passage and which burns the supplied hydrogen in the compressed air to generate combustion gas, and a gas turbine that is driven by the combustion gas;
and an exhaust heat recovery means for recovering heat generated in the gas turbine unit and heating a heat medium,
The heat medium heated by the exhaust heat recovery means is supplied to the ammonia decomposition device,
a second nitrogen flow passage through which the nitrogen from which the residual ammonia has been recovered in the recovery section flows is connected to the hydrogen supply passage;
a gas turbine system configured to be capable of supplying the mixed gas of the hydrogen and the nitrogen to the combustor . a second nitrogen flow passage through which the nitrogen from which the residual ammonia has been recovered in the recovery section flows is connected to the hydrogen supply passage;
2. The gas turbine system according to claim 1 , wherein the mixed gas of the hydrogen and the nitrogen is capable of being supplied to the combustor. 4. The gas turbine system according to claim 2 , further comprising a control unit that adjusts a mixture ratio of the hydrogen and the nitrogen in the mixed gas in response to a load fluctuation. The gas turbine system according to any one of claims 1 to 4, wherein the ammonia supply means supplies the ammonia at a supply pressure higher than atmospheric pressure. The gas turbine system according to any one of claims 1 to 5, further comprising a pressure reducing means for reducing the pressure on the hydrogen permeation side from the downstream side in the hydrogen flow direction so that the hydrogen permeation side of the membrane separation section is at a lower pressure than the catalyst packed section side. The gas turbine system according to any one of claims 1 to 6, further comprising a sweep gas supply means for supplying a sweep gas to the hydrogen permeation side of the membrane separation section.