gas turbine

Abstract

To make the concentration of nitrogen oxides (NOx) meet emission standards without enlarging the size of an exhaust denitrification device and improve thermal efficiency of a gas turbine that uses ammonia as fuel on a gas turbine.SOLUTION: A gas turbine that comprises at least a compressor, a combustor, and a turbine, and combusts ammonia as fuel in the combustor, the gas turbine further comprising a reducing agent supply device that supplies a reducing agent for reducing a nitrogen oxide in the combustion gas to a combustion gas flow passage between the combustor and the turbine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to gas turbines. This application claims priority based on PCT / JP2020 / 019693, filed in Japan on May 18, 2020, and the contents of that application are incorporated herein by reference. [Background technology]

[0002] Patent Document 1 below discloses a combustion device and a gas turbine system for co-combusting natural gas and ammonia in a combustor. This combustion device co-combusts gaseous ammonia as combustion ammonia in a combustor, and also burns nitrogen oxides (NOx) contained in the combustion gas. x To reduce ), ammonia for reduction is supplied to the downstream side of the turbine and the upstream side of the reduction catalyst chamber. Furthermore, Patent Document 2 below describes a method of burning ammonia as the sole fuel in the main combustor (dedicated combustion) and supplying it to the reheater to remove nitrogen oxides (NOx) from the exhaust gas. x A reheat ammonia gas turbine that reduces the concentration of ) is disclosed. This gas turbine supplies the exhaust gas from the reheater to the reheat gas turbine via a denitrification catalyst. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-162752 [Patent Document 2] Japanese Patent Application Publication No. 2015-031215 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] By the way, in each of the gas turbines mentioned above, a reduction catalyst chamber or a denitrification catalyst is used to reduce the nitrogen oxide concentration in the combustion gas or exhaust gas. However, since ammonia is burned as fuel, nitrogen oxides (NOx) derived from nitrogen atoms contained in ammonia (NH3) are also present.x The generation of ) is unavoidable. In other words, a large exhaust denitrification system is essential for ammonia-burning gas turbines.

[0005] However, increasing the size of exhaust gas denitrification equipment leads to various problems, including increased cost, space requirements, decreased overall efficiency, and worsened load fluctuation tracking capabilities. Therefore, nitrogen oxides (NOx) contained in the combustion gas are removed before the exhaust gas denitrification equipment. x The concentration of ) needs to be reduced.

[0006] Furthermore, while ammonia does not produce carbon dioxide (CO2) during combustion, the production volume of CO2-free ammonia derived from renewable energy is limited, making its efficient use, i.e., improvement of thermal efficiency, necessary. While it is easier to improve the thermal efficiency of larger gas turbines, larger gas turbines also consume larger amounts of ammonia, making them less suitable for large gas turbines that consume large quantities of CO2-free ammonia, which is produced in limited quantities. Therefore, measures are needed to improve the thermal efficiency of small and medium-sized gas turbines by taking advantage of the characteristics of ammonia combustion.

[0007] This disclosure is made in light of the issues described above and aims to address the following points. (1) Without increasing the size of the exhaust denitrification system, nitrogen oxides (NO x The concentration of ) must be brought into compliance with the emission standards. (2) To improve the thermal efficiency of ammonia-fueled gas turbines. [Means for solving the problem]

[0008] The gas turbine according to the first aspect of the present disclosure comprises at least a compressor, a combustor, and a turbine, and burns ammonia as fuel in the combustor, and includes a steam circulation means for recovering steam generated by the combustion of ammonia and circulating it back to the combustor.

[0009] In the gas turbine according to the first embodiment of the present disclosure, the steam circulation means includes a recovery device for recovering steam contained in the turbine exhaust gas as water, and a steam supply device for vaporizing the water and supplying it to the combustor, and the steam may be condensed and the water vaporized by heat exchange between the exhaust gas and the water.

[0010] In the gas turbine according to the first embodiment of the present disclosure, the recovery device may include a heat exchanger for exchanging heat between exhaust gas and water, and a gas-liquid separator for separating the water output from the heat exchanger from the remaining exhaust gas into gas-liquid and gas-liquid components. The steam supply device may also include a water pump for supplying the water output from the gas-liquid separator to the heat exchanger, and the heat exchanger itself.

[0011] In the gas turbine according to the first aspect of the present disclosure, a first mixing means may be provided for mixing at least a portion of the steam supplied by the steam supply device to the combustor with the ammonia before it is supplied to the combustor as fuel.

[0012] In the gas turbine according to the first aspect of the present disclosure, a second mixing means may be provided for mixing at least a portion of the ammonia before it is supplied as fuel to the combustor with water recovered by the recovery device.

[0013] In the gas turbine according to the first aspect of the present disclosure, a reducing agent supply means may be provided for supplying a portion of the ammonia before it is supplied as fuel to the combustor to the turbine as a reducing agent for reducing nitrogen oxides in the combustion gas.

[0014] A gas turbine according to a second aspect of the present disclosure comprises at least a compressor, a combustor, and a turbine, and burns ammonia as fuel in the combustor, and further comprises a combustion gas flow path between the combustor and the turbine and / or a reducing agent supply device that supplies a reducing agent for reducing nitrogen oxides in the combustion gas to the turbine.

[0015] In the gas turbine according to the second aspect of the present disclosure, the turbine is a multi-stage turbine in which a plurality of individual turbines are combined, and the reducing agent supply device may supply a reducing agent to an individual turbine in a stage where a denitration effect is expected or / and an individual combustion gas flow path connecting the individual turbines.

[0016] In the gas turbine according to the second aspect of the present disclosure, a cooling fluid supply device for supplying a cooling fluid to the turbine is further provided, and the reducing agent may be supplied after being mixed with the cooling fluid.

[0017] In the gas turbine according to the second aspect of the present disclosure, the reducing agent may be ammonia.

Advantages of the Invention

[0018] According to the present disclosure, it is possible to make the concentration of nitrogen oxides (NO x ) comply with the emission standards without increasing the size of the exhaust gas denitration device. Also, according to the present disclosure, it is possible to improve the thermal efficiency of a gas turbine that uses ammonia as fuel.

Brief Description of the Drawings

[0019] [Figure 1] It is a system configuration diagram showing the overall configuration of a gas turbine according to a first embodiment of the present disclosure. [Figure 2A] It is a first schematic diagram showing the turbine configuration and the reducing agent injection location in the first embodiment of the present disclosure. [Figure 2B] It is a second schematic diagram showing the turbine configuration and the reducing agent injection location in the first embodiment of the present disclosure. [Figure 3] It is a graph showing the simulation results of the denitration rate in the first embodiment of the present disclosure. [Figure 4] It is a system configuration diagram showing the overall configuration of a gas turbine according to a second embodiment of the present disclosure. [Figure 5] It is a system configuration diagram showing the overall configuration of a gas turbine according to a third embodiment of the present disclosure. [Modes for carrying out the invention]

[0020] Embodiments of this disclosure will be described below with reference to the drawings. [First Embodiment] First, a first embodiment of this disclosure will be described with reference to Figures 1 to 3. As shown in Figure 1, the gas turbine A according to the first embodiment comprises a compressor 1, a combustor 2, a turbine 3, a fuel supply device 4, a cooling air supply device 5, a reducing agent supply device 6, a waste heat recovery boiler 7, and an exhaust denitrification device 8. This gas turbine A is an ammonia-only burning type gas turbine in which ammonia supplied from the fuel supply device 4 is burned (exclusively) in the combustor 2 as the sole fuel X3.

[0021] The compressor 1 is an axial flow compressor equipped with, for example, multiple stages of alternating rotor blades and stator blades arranged along a rotating shaft, which pressurizes air X1 taken in from the atmosphere to a predetermined pressure and supplies it to the combustor 2. The rotating shaft of the compressor 1 is axially coupled to the rotating shaft of the turbine 3, and the compressor 1 is rotationally driven by the turbine 3.

[0022] The combustor 2 is equipped with a burner that injects compressed air X2 supplied from the compressor 1 and fuel X3 supplied from the fuel supply device 4 into the chamber, burning the fuel X3 with the compressed air X2 as an oxidizer. The combustor 2 supplies the high-temperature, high-pressure combustion gas X4 generated by the combustion reaction of the fuel X3 to the turbine 3 as a driving fluid.

[0023] The turbine 3 is an axial flow turbine equipped with, for example, multiple stages of alternating rotor blades and stator blades arranged along the rotating shaft, and is a prime mover that converts the kinetic energy of combustion gas X4 (driving fluid) into power. The turbine 3 rotates the compressor 1, to which the rotating shaft is axially coupled, using the power it generates. The turbine 3 also has an output shaft connected to a load, which rotates the load.

[0024] As shown in Figures 2A and 2B, such a turbine 3 is equipped with multiple (four) individual turbines 3a to 3d and five combustion gas passages 3e to 3i, and is a multi-stage turbine formed by combining these individual turbines 3a to 3d and combustion gas passages 3e to 3i. This turbine 3 discharges the exhaust gas X5, which has been recovered by the individual turbines 3a to 3d of each stage, to the waste heat recovery boiler 7.

[0025] Of the four individual turbines 3a to 3d, individual turbine 3a is the first-stage turbine located furthest upstream in the flow direction of the combustion gas X4. The inlet of this individual turbine 3a is connected to the outlet of the combustor 2 via the combustion gas flow path 3e. Furthermore, the outlet of this individual turbine 3a is connected to the inlet of individual turbine 3b via the combustion gas flow path 3f.

[0026] Individual turbine 3b is a second-stage turbine located second from the upstream in the flow direction of the combustion gas X4. The inlet of combustion gas X4 in individual turbine 3b is connected to the outlet of individual turbine 3a via the combustion gas flow path 3f. In addition, the outlet of individual turbine 3b is connected to the inlet of individual turbine 3c via the combustion gas flow path 3g.

[0027] Individual turbine 3c is a third-stage turbine located third from the upstream in the flow direction of the combustion gas X4. The inlet of combustion gas X4 in individual turbine 3c is connected to the outlet of individual turbine 3b via the combustion gas flow path 3g. Furthermore, the outlet of individual turbine 3c is connected to the inlet of individual turbine 3d via the combustion gas flow path 3h.

[0028] The individual turbine 3d is the fourth-stage turbine located furthest downstream in the flow direction of the combustion gas X4. The inlet of the combustion gas X4 in this individual turbine 3d is connected to the outlet of the individual turbine 3c via the combustion gas flow path 3h. Furthermore, the outlet of the combustion gas X4 in this individual turbine 3d is connected to the inlet of the waste heat recovery boiler 7 via the combustion gas flow path 3i.

[0029] The fuel supply device 4 comprises at least a fuel tank and a fuel pump, and supplies a predetermined flow rate of fuel X3 to the combustor 2. More specifically, the fuel supply device 4 supplies ammonia as fuel X3 to the combustor 2. As is well known, ammonia is generally available as a liquefied gas. The fuel supply device 4 receives such ammonia as fuel X3 from an external source and supplies it to the combustor 2.

[0030] The cooling air supply device 5 includes at least an air compressor and supplies cooling air X6 to the turbine 3 as a cooling fluid. This cooling air X6 is supplied to the inside of the turbine blades and stationary blades that make up the turbine 3, and flows out from the inside to the outside, thereby suppressing fatigue deterioration of the turbine 3 which is exposed to high-temperature combustion gases. Such a cooling air supply device 5 corresponds to the cooling fluid supply device of this disclosure.

[0031] The reducing agent supply device 6 comprises at least a reducing agent tank and a reducing agent pump, and supplies a predetermined flow rate of reducing agent X7 to the turbine 3 and the exhaust denitrification device 8. This reducing agent X7 is nitrogen oxide (NOx) contained in the combustion gas. x The reducing agent is a substance that can be expected to have a reducing effect on the gases, such as ammonia. More specifically, the reducing agent supply device 6 selectively supplies the reducing agent X7 to one of the individual turbines 3a to 3d or / or the combustion gas flow paths 3e to 3i.

[0032] In other words, the reducing agent supply device 6 supplies the reducing agent X7 to the combustion gas flow path between the combustor 2 and the turbine 3, and / or to the individual turbines and / or individual combustion gas flow paths of the turbine 3 where a denitrification effect is expected. Such a reducing agent supply device 6 corresponds to the reducing agent supply device of this disclosure.

[0033] The waste heat recovery boiler 7 is a steam generator that generates steam using the exhaust gas X5 supplied from the turbine 3 as a heat source, and is equipped with at least a gas flow pipe through which exhaust gas X5 flows and a water flow pipe through which water flows. The waste heat recovery boiler 7 discharges the exhaust gas X8 after waste heat recovery to the exhaust denitrification device 8.

[0034] The exhaust gas denitrification device 8 comprises at least a catalyst chamber filled with a denitrification catalyst and a sprayer that sprays a reducing agent X7 upstream of the denitrification catalyst, thereby reducing nitrogen oxides (NOx) contained in the exhaust gas X8 by flowing the exhaust gas X8 together with the reducing agent X7 through the denitrification catalyst. x The exhaust denitrification device 8 decomposes the exhaust gas X9, in which the nitrogen oxide concentration has been reduced to meet environmental standards, and releases it into the atmosphere.

[0035] Such an exhaust gas denitrification device 8 has the property of increasing in size depending on the flow rate of the exhaust gas X8 and / or the concentration of nitrogen oxides contained in the exhaust gas X8. That is, when the flow rate of the exhaust gas X8 increases, the size of the exhaust gas denitrification device 8 increases in order to make the exhaust gas X9 conform to environmental standards, and when the concentration of nitrogen oxides in the exhaust gas X8 increases, the size of the device also increases in order to make the exhaust gas X9 conform to environmental standards.

[0036] Therefore, in order to suppress the enlargement of the exhaust gas denitrification device 8, it is necessary to sufficiently reduce the concentration of nitrogen oxides in the area upstream of the exhaust gas denitrification device 8, that is, from the combustor 2 through which the combustion gas X4 or exhaust gases X5, X8, X9 flow to the waste heat recovery boiler 7.

[0037] Next, the operation of the gas turbine A according to the first embodiment will be described in detail with reference to Figure 3.

[0038] Figure 3 shows the results of a simulation of the change in denitrification rate with respect to temperature (K) and pressure (bar) in the field of reducing agent X7 when ammonia (fuel X3) is exclusively burned in the combustor 2. In Figure 3, the solid line represents the case when the pressure is 1 bar, the dotted line represents the case when the pressure is 10 bar, and the dashed line represents the case when the pressure is 20 bar.

[0039] More specifically, combustion gas X4 is a mixed gas containing 17% oxygen (O2), 6% water vapor (H2O), and 500 ppm nitric oxide (NO) within nitrogen (N2). In this simulation, the change in denitrification rate was determined when 500 ppm ammonia (NH3), equivalent in amount to nitric oxide (NO), was converted into combustion gas X4. Note that 1 bar is equal to 0.1 MPa (megapascals), as is well known.

[0040] These simulation results indicate that the denitrification rate increases with increasing pressure, and that the denitrification rate takes a positive value within a given temperature range, while taking a negative value in temperature ranges exceeding that range. In other words, these simulation results indicate that the nitrogen oxide concentration decreases in the temperature range of approximately 1100°C to approximately 1500°C, and conversely increases in temperature ranges exceeding approximately 1500°C.

[0041] The gas turbine A according to this first embodiment is based on these simulation results, and the reducing agent supply device 6 supplies the reducing agent X7 to locations in the turbine 3 where the denitrification rate can take a positive value, as shown in Figures 2A and 2B.

[0042] Figure 2A shows the case where gas turbine A according to the first embodiment is applied to a relatively large gas turbine. In this case, the properties of the combustion gas X4 at the outlet of combustor 2 are pressure: 20 bar, temperature: 1673 K, and nitrogen oxide concentration: 500 ppm. Furthermore, assuming that the turbine expansion coefficient of each individual turbine 3a to 3d is 1.7, the pressure, temperature, and nitrogen oxide concentration at the inlet and outlet of each individual turbine 3a to 3d are as shown in the three rows above.

[0043] Specifically, the pressure at the inlet of the first-stage individual turbine 3a is 20 bar, the temperature is 1673 K, and the nitrogen oxide concentration is 500 ppm, similar to the outlet of the combustor 2. The pressure at the outlet of the first-stage individual turbine 3a and the inlet of the second-stage individual turbine 3b is 11.8 bar and the temperature is 1480 K.

[0044] Also, the pressure at the outlet of the second-stage individual turbine 3b and the inlet of the third-stage individual turbine 3c is pressure: 6.9 bar, temperature: 1310 K. The pressure at the outlet of the third-stage individual turbine 3c and the inlet of the fourth-stage individual turbine 3d is pressure: 4.1 bar, temperature: 1159 K. Further, the pressure at the outlet of the fourth-stage individual turbine 3d is pressure: 2.4 bar, temperature: 1025 K.

[0045] Among the pressures and temperatures at the inlets and outlets of each of the individual turbines 3a to 3d like this, the locations that satisfy the condition that the denitration rate takes a positive value are the outlet of the second-stage individual turbine 3b and the inlet of the third-stage individual turbine 3c, and also the outlet of the third-stage individual turbine 3c and the inlet of the fourth-stage individual turbine 3d.

[0046] That is, the reducing agent supply device 6 in this first embodiment supplies the reducing agent X7 to the outlet of the two-stage individual turbine 3b and the outlet of the third-stage individual turbine 3c as shown in the figure. As a result, the nitrogen oxide concentration at the inlet of the third-stage individual turbine 3c is reduced to 240 ppm, and the nitrogen oxide concentration at the inlet of the fourth-stage individual turbine 3d is reduced to 154 ppm.

[0047] According to this first embodiment, for a relatively large gas turbine, it is possible to ensure a total denitration rate of about 69%. Also, the nitrogen oxide concentration of 154 ppm is at a level that can be treated by a normal-scale exhaust gas denitration device 8. Therefore, according to this first embodiment, for a relatively large gas turbine, it is possible to conform the concentration of nitrogen oxides (NO x ) to the emission standards without increasing the size of the exhaust gas denitration device 8.

[0048] Figure 2B also shows the case where gas turbine A according to the first embodiment is applied to a small to medium-sized gas turbine. In this case, the properties of the combustion gas X4 at the outlet of combustor 2 are pressure: 20 bar, temperature: 1373 K, and nitrogen oxide concentration: 500 ppm. Furthermore, if the turbine expansion coefficient of each individual turbine 3a to 3d is set to 1.7, the pressure, temperature, and nitrogen oxide concentration at the inlet and outlet of each individual turbine 3a to 3d will be as shown in the three rows above.

[0049] Specifically, the pressure at the inlet of the first-stage individual turbine 3a is 20 bar, the temperature is 1373 K, and the nitrogen oxide concentration is 500 ppm, similar to the outlet of the combustor 2. The pressure at the outlet of the first-stage individual turbine 3a and the inlet of the second-stage individual turbine 3b is 11.8 bar and the temperature is 1215 K.

[0050] Furthermore, the pressure at the outlet of the second-stage individual turbine 3b and the inlet of the third-stage individual turbine 3c is 6.9 bar and 1075 K, the pressure at the outlet of the third-stage individual turbine 3c and the inlet of the fourth-stage individual turbine 3d is 4.1 bar and 951 K, and the pressure at the outlet of the fourth-stage individual turbine 3d is 2.4 bar and 841 K.

[0051] Of the pressures and temperatures at the inlets and outlets of each individual turbine 3a to 3d, the locations that satisfy the condition that the denitrification rate takes a positive value are the outlet of the combustor 2 and the inlet of the first-stage individual turbine 3a, and the outlet of the first-stage individual turbine 3a and the inlet of the second-stage individual turbine 3b.

[0052] Therefore, the reducing agent supply device 6 supplies the reducing agent X7 to the outlet of the combustor 2 and the outlet of the first-stage individual turbine 3a, as shown in the figure. As a result, the nitrogen oxide concentration at the inlet of the first-stage individual turbine 3a decreases to 276 ppm, and the nitrogen oxide concentration at the inlet of the second-stage individual turbine 3b decreases to 132 ppm.

[0053] According to this first embodiment, it is possible to secure a total denitrification rate of approximately 74% for small and medium-sized gas turbines, and the nitrogen oxide concentration of 132 ppm is at a level that can be handled by a normal-sized exhaust denitrification device 8. Therefore, according to this first embodiment, even for small and medium-sized gas turbines, nitrogen oxides (NOx) can be denitrified without increasing the size of the exhaust denitrification device 8. x It is possible to bring the concentration of ) into compliance with emission standards.

[0054] Furthermore, according to this first embodiment, since ammonia can be used for both fuel X3 and reducing agent X7, the device configuration can be simplified. In addition, since ammonia, which has excellent cooling capacity, is supplied to the turbine 3 as reducing agent X7, the cooling capacity of the turbine 3 can be improved.

[0055] [Second Embodiment] Next, a second embodiment of this disclosure will be described with reference to Figure 4. In Figure 4, functional components identical to those in Figure 1 are denoted by the same reference numerals.

[0056] As shown in Figure 4, the gas turbine B according to the second embodiment includes a compressor 1, a combustor 2, a turbine 3, and a fuel supply device 4, in addition to a heat exchanger 12, a gas-liquid separator 13, and a water pump 14. The fuel supply device 4 includes a fuel tank 10 and a fuel pump 11. The heat exchanger 12, gas-liquid separator 13, and water pump 14, which are new functional components, constitute the steam circulation means of this disclosure, and recover the steam generated by the combustion of ammonia, which is the fuel X3, and circulate it back to the combustor 2.

[0057] As shown in equation (1) below, the combustion gas X4 generated by the ammonia combustion reaction contains a large amount of water. The gas turbine B according to this second embodiment utilizes this characteristic of the ammonia combustion reaction to improve thermal efficiency. 4NH4 + 3O2 → 2N2 + 6H2O (1)

[0058] The heat exchanger 12 exchanges heat between the exhaust gas X5 supplied from the turbine 3 and the water X11 supplied from the water pump 14, selectively condensing the water vapor contained in the exhaust gas X5 to produce a gas-liquid mixture X10, and vaporizing the water X11 to produce water vapor X13. The heat exchanger 12 supplies the gas-liquid mixture X10 to the gas-liquid separator 13 and supplies the water vapor X13 to the combustor 2.

[0059] The gas-liquid separator 13 separates water X11 from the residual gas X12 in the gas-liquid mixed water X10 by separating the gas and liquid. The gas-liquid separator 13 supplies the water X11 to the water pump 14 and discharges the residual gas X12 to a subsequent waste heat recovery boiler or exhaust denitrification device (not shown).

[0060] In other words, the heat exchanger 12 and the gas-liquid separator 13 constitute the recovery device of this disclosure, and recover the water vapor, i.e., the water vapor generated by the combustion of ammonia contained in the exhaust gas X5 of the turbine 3, as water X11.

[0061] The water pump 14 pressurizes the water X11 supplied from the gas-liquid separator 13 and supplies it to the heat exchanger 12. This water X11 is heated in the heat exchanger 12, vaporizes into steam X13, and is supplied to the combustor 2. In other words, the heat exchanger 12 and the water pump 14 constitute a steam supply device of this disclosure, vaporizing water X11 and supplying it to the combustor 2.

[0062] When this configured gas turbine B is applied to a small to medium-sized gas turbine with an output of 11 MW, the total thermal efficiency, as determined by simulation, is 35.7%. The conditions for this simulation are as follows:

[0063] (1) Fuel X3 (ammonia) supply rate: 123 kmol / h (2) Fuel (ammonia) supply temperature: ambient temperature (3) Fuel (ammonia) supply pressure: 10 atm (4) Inlet temperature of turbine 3: 1100℃ (5) Inlet pressure of turbine 3: 20 atm

[0064] Furthermore, the simulation results obtained along with the above thermal efficiency (35.7%) show that the power of the fuel supply device 4 (supply pump power) is 1kW, the power of the water pump 14 is 6kW, the power of the compressor 1 is 2281kW (air flow rate: 600kmol / h), the output of the turbine 3 is 6156kW, and the net output is 3867kW.

[0065] Based on these simulation results, when the heat exchanger 12, gas-liquid separator 13, and water pump 14 (i.e., the steam circulation means of this disclosure) are removed from gas turbine B, and a heat exchanger for exchanging heat between exhaust gas X5 and fuel X3 (ammonia) is added, the thermal efficiency of the gas turbine is calculated to be 29.0%. The simulation conditions in this case are substantially the same as those for gas turbine B described above, except that the inlet temperature of turbine 3 is 1400°C.

[0066] Furthermore, the simulation results obtained along with the above thermal efficiency (29.0%) show that the power of the fuel supply device 4 (supply pump power) is 1 kW, the power of the compressor 1 is 4068 kW (air flow rate: 1070 kmol / h), the output of the turbine 3 is 7207 kW, and the net output is 3138 kW.

[0067] In other words, with the gas turbine B according to this second embodiment, the steam generated by the combustion of fuel X3 (ammonia) is recovered and circulated back to the combustor 2, so when ammonia is used as fuel X3, it is possible to improve thermal efficiency.

[0068] Furthermore, since gas turbine B supplies steam X13 to combustor 2, it is possible to lower the temperature of combustion gas X4, thereby suppressing corrosion of turbine 3. Also, since gas turbine B supplies steam X13 to combustor 2, it is possible to reduce the amount of air supplied to combustor 2, thereby reducing the power of compressor 1.

[0069] [Third Embodiment] Next, a third embodiment of this disclosure will be described with reference to Figure 5. In Figure 5, functional components identical to those in Figure 4 are denoted by the same reference numerals.

[0070] The gas turbine C according to the third embodiment, as shown in Figure 5, includes a compressor 1, combustor 2, turbine 3, fuel supply device 4, heat exchanger 12, gas-liquid separator 13, and water pump 14, in addition to a first mixing pipe 21, a second mixing pipe 22, and a reducing agent supply pipe 23. The first mixing pipe 21, the second mixing pipe 22, and the reducing agent supply pipe 23, which are new functional components, may be added individually to the gas turbine B shown in Figure 4. In other words, only the first mixing pipe 21 may be added to the gas turbine B of Figure 4. Alternatively, only the second mixing pipe 22 may be added to the gas turbine B of Figure 4. Alternatively, only the reducing agent supply pipe 23 may be added to the gas turbine B of Figure 4.

[0071] The first mixing pipe 21 is a branch pipe that branches off from the steam supply pipe 31 connecting the heat exchanger 12 and the combustor 2, and is connected to the fuel supply pipe 32 connecting the fuel pump 11 and the combustor 2. The first mixing pipe 21 and the steam supply pipe 31 are equipped with flow control valves 21a and 31a that can adjust the amount of steam distributed from 0 to 100% according to various loads of the gas turbine C. This first mixing pipe 21 corresponds to the first mixing means of this disclosure, which mixes at least a portion of the steam supplied to the combustor 2 by the steam supply device with ammonia before it is supplied to the combustor 2 as fuel X3.

[0072] The second mixing pipe 22 is a branch pipe that branches off from the fuel supply pipe 32 connecting the fuel pump 11 and the combustor 2, and is connected to the water supply pipe 33 connecting the water pump 14 and the heat exchanger 12. The second mixing pipe 22 and the fuel supply pipe 32 are equipped with flow control valves 22a and 32a that can adjust the amount of ammonia distributed from 0 to 100% according to various loads of the gas turbine C. This second mixing pipe 22 corresponds to the second mixing means of this disclosure, which mixes at least a portion of the ammonia before it is supplied to the combustor 2 as fuel X3 with water recovered by the recovery device.

[0073] The reducing agent supply pipe 23 is a branch pipe that branches off from the fuel supply pipe 32 connecting the fuel pump 11 and the combustor 2 and is connected to the turbine 3. The reducing agent supply pipe 23 is equipped with a flow control valve 23a that can adjust the flow rate of ammonia. The connection position of the reducing agent supply pipe 23 to the turbine 3 may be the same as the connection position of the reducing agent supply device 6 of the first embodiment described above. This reducing agent supply pipe 23 corresponds to the reducing agent supply means of this disclosure, which supplies a portion of the ammonia before it is supplied to the combustor 2 as fuel X3 to the turbine 3 as a reducing agent for reducing nitrogen oxides in the combustion gas.

[0074] According to the first mixing pipe 21, liquid ammonia, which will become fuel X3, and the recovered water vapor are mixed in a gas-liquid mixture, and the liquid ammonia, which has absorbed water vapor, can be supplied to the combustor 2. Since ammonia mixes very well with water, liquid ammonia can be mixed with the recovered water vapor. Because water is present in the liquid ammonia that will become fuel X3, the calorific value decreases, and the local flame temperature decreases during combustion in the combustor 2. Therefore, NO in the combustor 2, which is a problem in ammonia combustion x This can reduce the generation of [unspecified substance]. In addition, the mixing of liquid ammonia, which becomes fuel X3, with the recovered steam generates heat of dissolution, which preheats fuel X3. Therefore, the thermal efficiency of gas turbine C can be improved.

[0075] Furthermore, the second mixing pipe 22 allows for the mixing of liquid ammonia, which will become fuel X3, with the recovered water, passing it through the heat exchanger 12, and supplying it to the combustor 2 via the fuel supply pipe 32. Since ammonia mixes very well with water, liquid ammonia and recovered water can be mixed. The presence of water in the liquid ammonia, which will become fuel X3, reduces the calorific value, and the local flame temperature decreases during combustion in the combustor 2. Therefore, NO emissions in the combustor 2, which are a challenge in ammonia combustion, are reduced. xThis reduces the generation of [unclear]. Furthermore, the mixing of liquid ammonia, which becomes fuel X3, with the recovered water generates heat of dissolution, which preheats fuel X3. This heat of dissolution from liquid-liquid mixing is more effective than the heat of dissolution from gas-liquid mixing described above. Additionally, the passage of liquid ammonia, which becomes fuel X3, through the heat exchanger 12 enables preheating and vaporization of fuel X3. These factors improve the thermal efficiency of the gas turbine C.

[0076] Furthermore, the reducing agent supply piping 23 allows the liquid ammonia that becomes fuel X3 and the liquid ammonia that becomes the reducing agent X7 (denitrifying agent) shown in Figure 1 above to be shared. Therefore, there is no need to install a separate reducing agent supply device 6, and the size of the device can be kept down.

[0077] This disclosure is not limited to the embodiments described above, and for example, the following modifications are possible. (1) In the embodiments described above, ammonia-fired gas turbines A and B have been described, but the disclosure is not limited thereto. The disclosure is also applicable to ammonia-co-fired gas turbines in which ammonia is co-fired with other fuels.

[0078] (2) In the above embodiments, the uses of gas turbines A and B were not described, but the uses of gas turbines A and B are, for example, for power generation. That is, the output shaft of turbine 3 is connected to the rotating shaft of a generator, and the generator is driven by the power of turbine 3.

[0079] (3) In the first embodiment described above, the case in which the turbine 3 is provided with four (four stages) individual turbines 3a to 3d is described, but the disclosure is not limited thereto. The number of stages (number) of individual turbines may be, for example, a two-stage configuration consisting of a high-pressure turbine and a low-pressure turbine.

[0080] (4) In the first embodiment described above, the reducing agent X7 and the cooling air X6 (cooling fluid) were supplied to the turbine 3 separately, but the disclosure is not limited thereto. For example, the reducing agent X7 may be mixed with the cooling air X6 and supplied to the turbine 3. In this case, it is conceivable to use an ejector equipped with a discharge nozzle for the reducing agent X7 in the flow path of the cooling air X6. By using such an ejector, the reducing agent X7 can be supplied to the turbine 3 using the kinetic energy of the cooling air X6, thereby reducing the power required to supply the reducing agent X7.

[0081] (5) In the first embodiment described above, ammonia was used as the reducing agent X7, but the disclosure is not limited thereto. Any substance that exhibits a reducing effect on nitrogen oxides may be used other than ammonia.

[0082] (6) In the second embodiment described above, a steam circulation means comprising a heat exchanger 12, a gas-liquid separator 13, and a water pump 14 was employed, but the disclosure is not limited thereto. It is also possible to mix water supplied by a separate system from the steam circulation means with a gas (such as ammonia). [Industrial applicability]

[0083] This disclosure can be used in gas turbines. [Explanation of Symbols]

[0084] A, B, C Gas Turbine 1. Compressor 2 Combustor 3 Turbines 3a~3d Individual Turbines 3e~3i Combustion gas flow path 4 Fuel supply device 5. Cooling air supply device 6. Reducing agent supply device 7. Waste heat recovery boiler 8 Exhaust denitration equipment 10 fuel tanks 11 Fuel pump 12 Heat exchanger 13 Gas-liquid separator 14 Water pump 21 1st mixing pipe 22 2nd mixing pipe 23 Reducing agent supply piping

Claims

1. A gas turbine comprising at least a compressor, a combustor, and a turbine, wherein ammonia is used as fuel and is burned in the combustor, The system includes a reducing agent supply device that supplies a reducing agent for reducing nitrogen oxides in the combustion gas to the combustion gas flow path between the combustor and the turbine. Gas turbine.

2. The device further comprises a cooling fluid supply device that supplies cooling fluid to the turbine, wherein the reducing agent is supplied mixed with the cooling fluid. The gas turbine according to claim 1.

3. The reducing agent is ammonia. The gas turbine according to claim 1 or 2.

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