Combustion system
The combustion system addresses NOx generation in ammonia-burning systems by dynamically switching between liquid and gaseous ammonia supplies, enhancing combustion stability and reducing emissions through optimized fuel phase control.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- IHI CORP
- Filing Date
- 2024-12-25
- Publication Date
- 2026-07-07
Smart Images
Figure 2026112956000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a combustion system.
Background Art
[0002] In recent years, in order to prevent global warming, reduction of carbon dioxide (CO2) emissions has been demanded. For this reason, technologies for burning ammonia instead of fossil fuels have attracted attention. For example, Patent Document 1 discloses a gas turbine system that obtains power by burning ammonia in a combustor.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When ammonia is burned, NOx (nitrogen oxides) is generated from a part of the nitrogen that forms ammonia. Therefore, in technologies using ammonia as a fuel, development of technologies capable of reducing the amount of NOx generated is desired.
[0005] In view of such problems, an object of this disclosure is to provide a combustion system capable of reducing the amount of NOx generated.
Means for Solving the Problems
[0006] To solve the above problems, the combustion system of this disclosure comprises a combustor for burning ammonia, a liquid ammonia line connected to the combustor and having a heater for heating liquid ammonia, a gaseous ammonia line connected to the combustor and having a vaporizer for vaporizing liquid ammonia, and a line switching device for switching the line connected to the combustor between the liquid ammonia line, the gaseous ammonia line, and the liquid ammonia line and the gaseous ammonia line.
[0007] The heater includes a first heat exchanger in which heat exchange takes place between a heat transfer medium supplied from a heat source and liquid ammonia flowing through a liquid ammonia line, and may further include a heat source switching device that switches the heat transfer medium supply source between a plurality of heat sources with different temperatures.
[0008] The heat source switching device may switch the supply source according to the temperature of the liquid ammonia delivered from the first heat exchanger.
[0009] The heat source switching device may switch the supply source according to the concentration of NOx contained in the exhaust gas discharged from the combustor.
[0010] The heat source switching device may switch the supply source so that the temperature of the heat transfer medium gradually increases.
[0011] The combustor is installed in a gas turbine, and the combustion system comprises a boiler connected to the gas turbine and a steam turbine connected to the boiler via a water line, and the multiple heat sources may include a water line.
[0012] The water line includes a first water line that supplies steam from the boiler to the steam turbine, and multiple heat sources may also include the first water line.
[0013] The vaporizer includes a second heat exchanger in which heat exchange takes place between steam flowing through a first water line and liquid ammonia flowing through a gaseous ammonia line, and the multiple heat sources may include the first water line upstream of the second heat exchanger and the first water line downstream of the second heat exchanger.
[0014] The water line includes a second water line that supplies water from the steam turbine to the boiler, and multiple heat sources may include a second water line.
[0015] The combustor is installed in the gas turbine, and the combustion system comprises a boiler connected to the gas turbine and a steam turbine connected to the boiler via a water line, and the multiple heat sources may include heat sources other than the water line. [Effects of the Invention]
[0016] According to this disclosure, the amount of NOx generated can be reduced. [Brief explanation of the drawing]
[0017] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a combustion system according to an embodiment of this disclosure. [Figure 2] Figure 2 is a flowchart showing the processing flow of a fuel supply method using the combustion system according to the present embodiment. [Figure 3] Figure 3 is a graph showing the change in ammonia flow rate [%] over time in the combustion system according to the same embodiment. [Figure 4] Figure 4 is a graph showing the relationship between the fuel-air ratio and NOx concentration in the combustion system according to the same embodiment. [Figure 5] Figure 5 is a graph showing the change in ammonia flow rate [%] over time in a modified example. [Modes for carrying out the invention]
[0018] The embodiments of the present disclosure will be described below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant descriptions, and elements not directly related to the present disclosure are not shown.
[0019] [1. Combustion System] First, referring to FIG. 1, a combustion system 100 according to an embodiment of the present disclosure will be described. FIG. 1 is a schematic diagram showing the configuration of the combustion system 100 according to the present embodiment. In FIG. 1, the solid arrows indicate the flow of ammonia, air, and combustion exhaust gas. In FIG. 1, the dashed arrows indicate the flow of water and steam.
[0020] As shown in FIG. 1, the combustion system 100 according to the present embodiment includes a combustor 112, a liquid ammonia line 120, a gaseous ammonia line 130, and a line switching device 140. Further, the combustion system 100 may further include a denitration device 150, a boiler 160, a water line 170, a steam turbine 180, a heat medium circulation device 200, a heat source switching device 210, a NOx sensor 230, a temperature sensor 232, and a control device 250.
[0021] As shown in FIG. 1, the combustor 112 burns ammonia. The combustor 112 is provided, for example, in a gas turbine 110. The gas turbine 110 includes a compressor 114 and a turbine 116 in addition to the combustor 112. Note that the gas turbine 110 may further include other components.
[0022] The compressor 114 pressurizes air and sends the pressurized air to the combustor 112. The compressor 114 may have, for example, an inlet guide vane. The inlet guide vane adjusts, for example, the flow rate of the air sucked into the compressor 114 according to an instruction from the control device 250 described later.
[0023] The combustor 112 receives air pressurized by the compressor 114 and burns ammonia in this air. The exhaust gas produced by the combustion is sent from the combustor 112 to the turbine 116.
[0024] The turbine 116 is rotated by the exhaust gas. The rotational force of the turbine 116 is used to operate the generator 118. In other embodiments, the rotational force of the turbine 116 may be used for other devices. The electricity generated by the generator 118 is supplied to other devices (not shown) within the combustion system 100 or to external devices.
[0025] The combustor 112 is connected to the ammonia supply source 10 via the main ammonia line 102, the liquid ammonia line 120, and the gaseous ammonia line 130. The ammonia supply source 10 is, for example, a tank in which liquid ammonia is stored. The combustor 112 burns the ammonia supplied from the ammonia supply source 10 with air.
[0026] The main ammonia line 102 connects the ammonia supply source 10 to the liquid ammonia line 120 and the gaseous ammonia line 130. The main ammonia line 102 is equipped with a main pump 104 and a flow control valve 106. The suction side of the main pump 104 is connected to the ammonia supply source 10. The discharge side of the main pump 104 is connected to the flow control valve 106. The main pump 104 pressurizes and discharges liquid ammonia. The flow control valve 106 adjusts the flow rate of liquid ammonia flowing through the main ammonia line 102, thereby adjusting the flow rate of ammonia supplied to the combustor 112.
[0027] The liquid ammonia line 120 has a heater 122 for heating liquid ammonia and is connected to the combustor 112. In this embodiment, the liquid ammonia line 120 connects the main ammonia line 102 to the combustor 112. In addition to the heater 122, the liquid ammonia line 120 may also have a pump 124. The suction side of the pump 124 is connected to the main ammonia line 102. The discharge side of the pump 124 is connected to the heater 122. The pump 124 pressurizes and discharges the liquid ammonia. By providing the pump 124, the pressure of the liquid ammonia supplied to the combustor 112 through the liquid ammonia line 120 can be easily brought to the target pressure.
[0028] The heater 122 heats liquid ammonia. The ammonia discharged from the heater 122 is in liquid form. The heater 122 heats the liquid ammonia to, for example, below its boiling point. The heater 122 may include, for example, a first heat exchanger 122a in which heat exchange takes place between a heat transfer medium supplied from a heat source and liquid ammonia flowing through the liquid ammonia line 120.
[0029] The gaseous ammonia line 130 has a vaporizer 132 that vaporizes liquid ammonia and is connected to the combustor 112. In this embodiment, the gaseous ammonia line 130 connects the main ammonia line 102 and the combustor 112. The vaporizer 132 may include, for example, a second heat exchanger 132a in which heat exchange takes place between steam flowing through the first water line 172 (described later) and liquid ammonia flowing through the gaseous ammonia line 130. The second heat exchanger 132a heats and vaporizes the liquid ammonia by exchanging heat between the steam, which is the heat transfer medium, and the liquid ammonia.
[0030] Furthermore, the gaseous ammonia line 130 may also have a compressor 134 in addition to the vaporizer 132. The compressor 134 pressurizes the gaseous ammonia vaporized by the vaporizer 132. By providing the compressor 134, the pressure of the gaseous ammonia supplied to the combustor 112 through the gaseous ammonia line 130 can be easily brought to the target pressure.
[0031] The line switching device 140 switches the lines connected to the combustor 112 between the liquid ammonia line 120, the gaseous ammonia line 130, and the liquid ammonia line 120 and the gaseous ammonia line 130. For example, the line switching device 140 switches the ammonia supply state between a first state in which gaseous ammonia is supplied to the combustor 112 from the gaseous ammonia line 130, a second state in which liquid ammonia is supplied to the combustor 112 from the liquid ammonia line 120, and a third state in which gaseous ammonia from the gaseous ammonia line 130 and liquid ammonia from the liquid ammonia line 120 are supplied to the combustor 112.
[0032] The line switching device 140 may include, for example, switching valves 140l and 140g. Switching valve 140l is located upstream of pump 124 in the liquid ammonia line 120. Switching valve 140l controls the flow rate of liquid ammonia supplied to combustor 112 through the liquid ammonia line 120. Switching valve 140g is located upstream of vaporizer 132 in the gaseous ammonia line 130. Switching valve 140g controls the flow rate of gaseous ammonia supplied to combustor 112 through the gaseous ammonia line 130 by controlling the flow rate of liquid ammonia supplied to vaporizer 132.
[0033] For example, the first state described above is achieved by closing the switching valve 140l and opening the switching valve 140g. The second state is achieved by opening the switching valve 140l and closing the switching valve 140g. The third state is achieved by opening both the switching valve 140l and the switching valve 140g.
[0034] The line switching device 140 may include a single three-way valve instead of the switching valves 140l and 140g. In this case, the three-way valve is preferably installed at the connection point of the main ammonia line 102, the liquid ammonia line 120, and the gaseous ammonia line 130. This three-way valve adjusts the ratio of the flow rate of liquid ammonia flowing into the liquid ammonia line 120 to the flow rate of liquid ammonia flowing into the vaporizer 132 of the gaseous ammonia line 130.
[0035] The denitrification unit 150 receives exhaust gas sent from the turbine 116. The denitrification unit 150 decomposes NOx contained in the exhaust gas. For example, ammonia is supplied to the denitrification unit 150, and the denitrification unit 150 decomposes NOx into nitrogen and water (steam) using ammonia. The denitrification unit 150 may also be installed inside the boiler 160, which will be described later. The combustion system 100 according to this embodiment can suppress the amount of NOx discharged to the outside from the chimney 20 by including the denitrification unit 150.
[0036] The boiler 160 is connected to the turbine 116 of the gas turbine 110 via a denitrification unit 150. The boiler 160 generates steam using the heat from the exhaust gas. The boiler 160 is also called a waste heat recovery boiler. The exhaust gas discharged from the boiler 160 is exhausted to the outside through the chimney 20.
[0037] The water line 170 connects the boiler 160 and the steam turbine 180. The water line 170 includes, for example, a first water line 172 and a second water line 174. The first water line 172 supplies steam from the boiler 160 to the steam turbine 180. The first water line 172 connects the steam outlet of the boiler 160 to the steam turbine 180.
[0038] The steam turbine 180 is rotated by steam supplied from the boiler 160 through the first water line 172. The rotational force of the steam turbine 180 is used to operate the generator 182. In other embodiments, the rotational force of the steam turbine 180 may be used for other devices. The electricity generated by the generator 182 is supplied to other devices (not shown) within the combustion system 100 or to external devices.
[0039] The second water line 174 supplies water from the steam turbine 180 to the boiler 160. The second water line 174 connects the steam outlet of the steam turbine 180 to the water inlet of the boiler 160. The second water line 174 may have a condenser 174a and a feedwater pump 174b. Steam exhausted from the steam turbine 180 is supplied to the condenser 174a. The condenser 174a condenses the steam back into water. The suction side of the feedwater pump 174b is connected to the condenser 174a. The discharge side of the feedwater pump 174b is connected to the water inlet of the boiler 160. The feedwater pump 174b supplies the water in the condenser 174a to the boiler 160 through the second water line 174.
[0040] The heat transfer medium circulation device 200 circulates the steam generated in the boiler 160 to the second heat exchanger 132a of the vaporizer 132. The heat transfer medium circulation device 200 includes, for example, a heat transfer medium supply line 202, a flow control valve 204, and a heat transfer medium recovery line 206. The heat transfer medium supply line 202 connects the first water line 172 of the water line 170 to the inlet of the heat transfer medium in the second heat exchanger 132a of the vaporizer 132. The flow control valve 204 is provided in the heat transfer medium supply line 202. The flow control valve 204 adjusts the flow rate of steam flowing through the heat transfer medium supply line 202. The heat transfer medium recovery line 206 connects the outlet of the heat transfer medium in the second heat exchanger 132a of the vaporizer 132 to the condenser 174a of the second water line 174 of the water line 170. The heat transfer medium recovery line 206 may be connected to the outlet of the heat transfer medium of the second heat exchanger 132a of the vaporizer 132 and to the flow path through which water flows in the boiler 160.
[0041] The heat source switching device 210 switches the source of the heat transfer medium supplied to the first heat exchanger 122a of the heater 122 between a plurality of heat sources with different temperatures. The plurality of heat sources include, for example, the first water line 172 and / or the second water line 174 of the water line 170. In this embodiment, the plurality of heat sources may include the part of the first water line 172 upstream of the second heat exchanger 132a of the vaporizer 132, the part of the first water line 172 downstream of the second heat exchanger 132a of the vaporizer 132, and the second water line 174.
[0042] The heat source switching device 210 includes, for example, a water supply line 212, a flow control valve 214, a first steam supply line 216, a flow control valve 218, a second steam supply line 220, a flow control valve 222, and a water recovery line 224.
[0043] The water supply line 212 connects the second water line 174 of the water line 170 to the inlet of the heat transfer medium of the first heat exchanger 122a of the heater 122. A flow rate control valve 214 is provided in the water supply line 212. The flow rate control valve 214 adjusts the flow rate of water flowing through the water supply line 212. The first steam supply line 216 connects the first water line 172 of the water line 170 to the inlet of the heat transfer medium of the first heat exchanger 122a of the heater 122 via the heat transfer medium supply line 202 of the heat transfer medium circulation device 200. A flow rate control valve 218 controls the flow rate of steam flowing through the first steam supply line 216. The second steam supply line 220 connects the heat transfer medium recovery line 206 of the heat transfer medium circulation device 200 to the inlet of the heat transfer medium of the first heat exchanger 122a of the heater 122. The flow control valve 222 adjusts the flow rate of steam flowing through the second steam supply line 220.
[0044] The water recovery line 224 connects the outlet of the heat transfer medium of the first heat exchanger 122a of the heater 122 to the condenser 174a of the water line 170 via the heat transfer medium recovery line 206 of the heat transfer medium circulation device 200. The water recovery line 224 is connected downstream of the connection point of the second steam supply line 220 in the heat transfer medium recovery line 206 of the heat transfer medium circulation device 200.
[0045] The heat source switching device 210 switches the supply source of the heat transfer medium sent to the first heat exchanger 122a of the heater 122 between the upstream side of the first water line 172 beyond the second heat exchanger 132a of the vaporizer 132, the downstream side of the first water line 172 beyond the second heat exchanger 132a of the vaporizer 132, and the second water line 174 by opening and closing the flow control valves 214, 218, and 222.
[0046] Specifically, the heat source switching device 210 switches the supply source of the heat transfer medium sent to the first heat exchanger 122a of the heater 122 to the second water line 174 by opening the flow control valve 214 and closing the flow control valves 218 and 222. The heat source switching device 210 also switches the supply source of the heat transfer medium sent to the first heat exchanger 122a of the heater 122 to a point upstream of the second heat exchanger 132a of the vaporizer 132 on the first water line 172 by opening the flow control valve 218 and closing the flow control valves 214 and 222. The heat source switching device 210 switches the heat transfer medium supply source to the first heat exchanger 122a of the heater 122 to a side of the first water line 172 downstream of the second heat exchanger 132a of the vaporizer 132 by opening the flow control valve 222 and closing the flow control valves 214 and 218.
[0047] The NOx sensor 230 detects the concentration of NOx contained in the exhaust gas discharged from the combustor 112. The NOx sensor 230 also detects the concentration of NOx contained in the exhaust gas discharged from, for example, the boiler 160.
[0048] The temperature sensor 232 detects the temperature of the liquid ammonia discharged from the first heat exchanger 122a of the heater 122.
[0049] The control device 250 includes one or more processors 250a and one or more memories 250b connected to the processors 250a. The processors 250a include, for example, a CPU (Central Processing Unit). The memories 250b include, for example, ROM (Read Only Memory) and RAM (Random Access Memory). ROM is a memory element that stores programs and arithmetic parameters used by the CPU. RAM is a memory element that temporarily stores data such as variables and parameters used in processing performed by the CPU.
[0050] In this embodiment, the control device 250 receives, for example, a request output from the gas turbine 110 from an external source, and controls the flow control valve 106, the line switching device 140, and the heat transfer medium circulation device 200 according to this request output.
[0051] Furthermore, the control device 250 receives the output of the NOx sensor 230 and / or the temperature sensor 232 and controls the operation of the heat source switching device 210.
[0052] For example, the control device 250 controls the heat source switching device 210 according to the value detected by the NOx sensor 230, and switches the supply source of the heat transfer medium supplied to the heater 122. For example, the control device 250 controls the heat source switching device 210 so that the value detected by the NOx sensor 230 falls below a predetermined concentration. In this case, the control device 250 controls the heat source switching device 210 so that the supply source of the heat transfer medium is switched so that the temperature of the heat transfer medium sent to the heater 122 gradually increases. For example, the control device 250 may control the heat source switching device 210 to switch the supply source of the heat transfer medium supplied to the heater 122 in the following order: second water line 174, the upstream side of the first water line 172 beyond the second heat exchanger 132a of the vaporizer 132, and the downstream side of the first water line 172 beyond the second heat exchanger 132a of the vaporizer 132. In other words, the control device 250 may open the valves in the order of flow control valve 214, flow control valve 218, and flow control valve 222. Immediately after startup, the flow rate of steam generated in the boiler 160 is low, so the amount of heat required to vaporize liquid ammonia cannot be obtained. Therefore, when the flow rate of steam generated in the boiler 160 is low, such as immediately after startup, the control device 250 sets the source of the heat transfer medium supplied to the heater 122 to, for example, first the second water line 174 (opening flow control valve 214), and then the part of the first water line 172 upstream of the second heat exchanger 132a of the vaporizer 132 (opening flow control valve 218). Then, when the flow rate of steam generated in boiler 160 reaches the amount of heat required to vaporize liquid ammonia, control device 250 sets the source of the heat transfer medium supplied to heater 122 to the downstream side of the second heat exchanger 132a of vaporizer 132 in the first water line 172 (opens flow control valve 222). This allows the temperature of the heat transfer medium supplied to heater 122 to be gradually increased while the liquid ammonia is suitably vaporized in vaporizer 132. As a result, the temperature of the liquid ammonia heated by heater 122 and supplied to combustor 112 can be increased. This improves ignition in combustor 112 and improves combustion stability. Consequently, NOx contained in the exhaust gas can be reduced.
[0053] For example, the control device 250 controls the heat source switching device 210 according to the value detected by the temperature sensor 232, and switches the supply source of the heat transfer medium supplied to the heater 122. For example, the control device 250 controls the heat source switching device 210 so that the value detected by the temperature sensor 232 is above a predetermined temperature. In this case, the control device 250 controls the heat source switching device 210 so that the supply source of the heat transfer medium is switched so that the temperature of the heat transfer medium sent to the heater 122 gradually increases. For example, the control device 250 may control the heat source switching device 210 to switch the supply source of the heat transfer medium supplied to the heater 122 in the following order: second water line 174, the upstream side of the first water line 172 above the second heat exchanger 132a of the vaporizer 132, and the downstream side of the first water line 172 above the second heat exchanger 132a of the vaporizer 132. In other words, the control device 250 may open the valves in the order of flow control valve 214, flow control valve 218, and flow control valve 222. Immediately after startup, the flow rate of steam generated in the boiler 160 is low, so the amount of heat required to vaporize liquid ammonia cannot be obtained. Therefore, when the flow rate of steam generated in the boiler 160 is low, such as immediately after startup, the control device 250 sets the source of the heat transfer medium supplied to the heater 122 to, for example, first the second water line 174 (opening flow control valve 214), and then the part of the first water line 172 upstream of the second heat exchanger 132a of the vaporizer 132 (opening flow control valve 218). Then, when the flow rate of steam generated in the boiler 160 reaches the amount of heat required to vaporize the liquid ammonia, the control device 250 sets the source of the heat transfer medium supplied to the heater 122 to the downstream side of the second heat exchanger 132a of the vaporizer 132 in the first water line 172 (opening the flow control valve 222). This allows the liquid ammonia to be vaporized appropriately in the vaporizer 132 while efficiently raising the temperature of the heat transfer medium supplied to the heater 122 to above a predetermined temperature. As a result, the temperature of the liquid ammonia heated by the heater 122 and supplied to the combustor 112 can be increased. This improves the ignition performance in the combustor 112 and improves combustion stability. Consequently, the amount of NOx contained in the exhaust gas can be reduced.
[0054] [2. Fuel supply method using a combustion system] Next, a fuel supply method using the combustion system 100 according to this embodiment will be described with reference to Figures 2 to 4. Figure 2 is a flowchart showing the processing flow of the fuel supply method using the combustion system 100 according to this embodiment. Figure 3 is a graph showing the change in ammonia flow rate [%] over time in the combustion system 100 according to this embodiment. In Figure 3, the vertical axis represents ammonia flow rate [%], and the horizontal axis represents time. Figure 4 is a graph showing the relationship between the fuel-air ratio and NOx concentration in the combustion system 100 according to this embodiment. In Figure 4, the vertical axis represents NOx concentration [ppm], and the horizontal axis represents the fuel-air ratio.
[0055] As shown in Figure 2, first, in step S110, the control device 250 operates the main pump 104 to pressurize the liquid ammonia flowing from the ammonia supply source 10 into the main ammonia line 102. Then, in step S112, the control device 250 controls the flow control valve 106 to adjust the flow rate of liquid ammonia flowing through the main ammonia line 102. By adjusting the flow rate of liquid ammonia, the flow rate of fuel supplied to the combustor 112 is adjusted. Also in step S112, the control device 250 receives the requested output from the gas turbine 110. The control device 250 determines the flow rate of fuel supplied to the combustor 112 according to this requested output. The fuel flow rate is determined to have a positive correlation with the requested output. That is, the fuel flow rate is determined so that as the requested output increases, the fuel flow rate increases. Then, the control device 250 controls the opening of the flow control valve 106 so that the flow rate of fuel supplied to the combustor 112 becomes the determined flow rate.
[0056] Furthermore, in step S114, the control device 250 operates the water line 170. For example, the control device 250 operates the feedwater pump 174b of the water line 170. This supplies water from the condenser 174a to the boiler 160.
[0057] Next, in steps S116 and S118, the control device 250 determines which of the above-mentioned first, second, and third states to select as the ammonia supply state. Specifically, in step S116, the control device 250 determines whether or not to set the ammonia supply state to the first state. If it is determined in step S116 that the ammonia supply state should not be the first state (NO in step S116), the process moves to step S118. In step S118, the control device 250 determines whether or not to set the ammonia supply state to the second state. If it is determined in step S118 that the ammonia supply state should not be the second state (NO in step S118), the process moves to step S140 in order to set the ammonia supply state to the third state.
[0058] Referring to Figure 3, the method for determining the ammonia supply state by the control device 250 will be explained. In Figure 3, the solid line shows the change in total ammonia flow rate, the dashed line shows the change in liquid ammonia flow rate, and the dotted line shows the change in gaseous ammonia flow rate. As shown by the solid line in Figure 3, the amount of ammonia supplied to the gas turbine 110 gradually increases over time from startup until rated operation. Also, when the requested output is less than the rated output, the flow rate of ammonia supplied to the combustor 112 is less than the flow rate of ammonia supplied to the combustor 112 when the requested output is the rated output. Here, if the total ammonia flow rate [%] when the requested output is the rated output is 100[%], then the total ammonia flow rate [%] before startup is 0[%]. Also, let the total ammonia flow rate [%] when the requested output is less than the rated output, at a predetermined output, be, for example, α[%].
[0059] If the total ammonia flow rate [%] determined according to the requested output is greater than 0 [%] and less than α [%], the control device 250 selects the second state from the first, second, and third states. The second state is a state in which only liquid ammonia is supplied to the combustor 112 as fuel, as described above. If the total ammonia flow rate [%] determined according to the requested output is α [%], the control device 250 selects the third state from the first, second, and third states. The third state is a state in which both liquid ammonia and gaseous ammonia are supplied to the combustor 112 as fuel, as described above. If the total ammonia flow rate [%] determined according to the requested output is greater than α [%], the control device 250 selects the first state from the first, second, and third states. The first state is a state in which only gaseous ammonia is supplied to the combustor 112 as fuel, as described above. Thus, the control device 250 selects the second state as the ammonia supply state at startup, then switches the ammonia supply state from the second state to the third state, and subsequently switches the ammonia supply state from the third state to the first state to transition to rated operation.
[0060] Returning to Figure 2, when the control device 250 selects the first state as the ammonia supply state (YES in step S116), the control device 250 controls the line switching device 140 in step S120 to switch the line connected to the combustor 112 to the gaseous ammonia line 130. Specifically, the control device 250 closes the switching valve 140l of the line switching device 140 and opens the switching valve 140g. As a result, liquid ammonia is guided to the vaporizer 132 through the main ammonia line 102 and the switching valve 140g, where it becomes gaseous ammonia. The gaseous ammonia is then supplied to the combustor 112 through the gaseous ammonia line 130. Note that because the switching valve 140l is closed, the liquid ammonia pressurized by the main pump 104 is not supplied to the liquid ammonia line 120. Therefore, in the first state, which is executed at high flow rates, only gaseous ammonia is supplied to the combustor 112 as fuel.
[0061] Furthermore, in the first state, the control device 250 controls the heat transfer medium circulation device 200 to operate the vaporizer 132 (step S122). Specifically, the control device 250 opens the flow rate control valve 204 of the heat transfer medium circulation device 200. As a result, the steam flowing through the first water line 172 is supplied as a heat transfer medium to the second heat exchanger 132a of the vaporizer 132. Note that in step S122, the control device 250 does not operate the heater 122. In other words, in step S122, the control device 250 closes the flow rate control valves 214, 218, and 222 of the heat source switching device 210.
[0062] Furthermore, when the combustion system 100 is started, if the control device 250 selects the second state as the ammonia supply state (YES in step S118), the control device 250 controls the line switching device 140 in step S130 to switch the line connected to the combustor 112 to the liquid ammonia line 120. Specifically, the control device 250 closes the switching valve 140g of the line switching device 140 and opens the switching valve 140l. As a result, liquid ammonia is supplied to the combustor 112 through the liquid ammonia line 120. Note that because the switching valve 140g is closed, the liquid ammonia pressurized by the main pump 104 is not supplied to the gaseous ammonia line 130. Therefore, in the second state, which is executed at low flow rates, only liquid ammonia is supplied to the combustor 112 as fuel.
[0063] Furthermore, in the second state, the control device 250 controls the heat source switching device 210 to operate the heater 122 (step S132). For example, in the second state, the control device 250 controls the heat source switching device 210 to switch the supply source of the heat transfer medium sent to the heater 122 to the second water line 174, or to the upstream side of the second heat exchanger 132a of the vaporizer 132 in the first water line 172. Note that in step S132, the control device 250 does not operate the vaporizer 132. In other words, in step S132, the control device 250 closes the flow rate control valve 204 of the heat transfer medium circulation device 200. For this reason, the heat source switching device 210 does not switch the supply source of the heat transfer medium sent to the heater 122 to the downstream side of the second heat exchanger 132a of the vaporizer 132 in the first water line 172.
[0064] If the control device 250 selects the third state as the ammonia supply state (NO in step S118), the control device 250 controls the line switching device 140 in step S140 to switch the lines connected to the combustor 112 to the liquid ammonia line 120 and the gaseous ammonia line 130. Specifically, the control device 250 opens the switching valves 140l and 140g of the line switching device 140. For example, the control device 250 sets the opening degree of the switching valves 140l and 140g of the line switching device 140 to 50%. As a result, liquid ammonia flows into the liquid ammonia line 120 through the main ammonia line 102 and the switching valve 140l, and is supplied to the combustor 112 through the liquid ammonia line 120. The liquid ammonia is also led to the vaporizer 132 through the main ammonia line 102 and the switching valve 140g, where it becomes gaseous ammonia. Then, gaseous ammonia is supplied to the combustor 112 through the gaseous ammonia line 130. Therefore, in the third state, which is performed at an α[%] flow rate between low and high flow rates, both liquid ammonia and gaseous ammonia are supplied to the combustor 112 as fuel.
[0065] Furthermore, in the third state, the control device 250 controls the heat transfer medium circulation device 200 to operate the vaporizer 132 and controls the heat source switching device 210 to operate the heater 122 (step S142). Specifically, the control device 250 opens the flow control valve 204 of the heat transfer medium circulation device 200. As a result, steam flowing through the first water line 172 is supplied as a heat transfer medium to the second heat exchanger 132a of the vaporizer 132.
[0066] Furthermore, the control device 250 controls, for example, the heat source switching device 210 to switch the supply source of the heat transfer medium sent to the heater 122 to the second water line 174, the first water line 172 upstream of the second heat exchanger 132a of the vaporizer 132, or the first water line 172 downstream of the second heat exchanger 132a of the vaporizer 132.
[0067] In the second and third states, the control device 250 may, for example, control the heat source switching device 210 in accordance with the value detected by the NOx sensor 230 to switch the supply source of the heat transfer medium sent to the heater 122. Also, in the second state, the control device 250 may, for example, control the heat source switching device 210 in accordance with the value detected by the temperature sensor 232 to switch the supply source of the heat transfer medium supplied to the heater 122.
[0068] Incidentally, as shown in Figure 3, when transitioning from a low flow rate to a high flow rate via an α[%] flow rate, the α[%] flow rate is maintained for a predetermined time or longer. In the third state, which is executed at the α[%] flow rate, during this predetermined time, the switching valve 140l is gradually closed over time, and the flow rate of liquid ammonia supplied to the combustor 112 gradually decreases over time. In the third state, during this predetermined time, the switching valve 140g is gradually opened over time, and the flow rate of gaseous ammonia supplied to the combustor 112 gradually increases over time. Similarly, when transitioning from a high flow rate to a low flow rate via an α[%] flow rate, the α[%] flow rate is maintained for a predetermined time or longer. In the third state, which is executed at the α[%] flow rate, during this predetermined time, the switching valve 140g is gradually closed over time, and the flow rate of gaseous ammonia supplied to the combustor 112 gradually decreases over time. In the third state, during this predetermined time, the switching valve 140l gradually opens over time, and the flow rate of liquid ammonia supplied to the combustor 112 gradually increases over time.
[0069] When ammonia is used as fuel for the gas turbine 110, some of the nitrogen that forms the ammonia becomes NOx. The amount of NOx produced depends on the flow rate of the ammonia used as fuel and the fuel-air ratio. If the flow rate of the ammonia used as fuel is high, the amount of NOx produced will be high, and if the flow rate of the ammonia used as fuel is low, the amount of NOx produced will be low. Also, as shown in Figure 4, the NOx concentration in the exhaust gas is maximum when the fuel-air ratio is a predetermined value r. The NOx concentration gradually decreases as the fuel-air ratio becomes smaller than the predetermined value r. Conversely, the NOx concentration gradually decreases as the fuel-air ratio becomes larger than the predetermined value r.
[0070] Therefore, the control device 250 according to this embodiment controls the fuel-air ratio so that the value of the fuel-air ratio does not fall within a predetermined fuel-air ratio range R where the NOx concentration is higher than a predetermined value c. As described above, the control device 250 determines the flow rate of ammonia (fuel) according to the requested output. Then, based on the determined ammonia flow rate, the control device 250 determines the opening degree of the intake volume regulator of the compressor 114 of the gas turbine 110. Then, the control device 250 controls the intake volume regulator of the compressor 114 of the gas turbine 110 so that the opening degree is determined. At this time, the control device 250 determines the opening degree of the intake volume regulator so that the value of the fuel-air ratio, which is the ratio of the determined ammonia flow rate to the flow rate of air drawn in by the compressor 114, does not fall within the predetermined fuel-air ratio range R. As a result, the combustion system 100 according to this embodiment can further suppress the generation of NOx in the combustor 112.
[0071] [3. Summary] The combustion system 100 according to this embodiment has been described in detail above.
[0072] The combustion system 100 according to this embodiment includes a combustor 112 for burning ammonia, a heater 122 for heating liquid ammonia and a liquid ammonia line 120 connected to the combustor 112, a vaporizer 132 for vaporizing liquid ammonia and a gaseous ammonia line 130 connected to the combustor 112, and a line switching device 140 that switches the lines connected to the combustor 112 between the liquid ammonia line 120 and the gaseous ammonia line 130.
[0073] As described above, the combustion system 100 according to this embodiment can supply gaseous ammonia as fuel to the combustor 112, or it can supply liquid ammonia as fuel to the combustor 112. When liquid ammonia is supplied to the combustor 112, misfires and other problems are suppressed, and the fuel can be burned stably. On the other hand, when gaseous ammonia is supplied to the combustor 112, the generation of NOx can be suppressed.
[0074] Incidentally, at low flow rates, although there is a high possibility of fuel misfire, the amount of NOx generated is low because the ammonia flow rate itself is low. On the other hand, at high flow rates, although there is a low possibility of fuel misfire, the amount of NOx generated is high because the ammonia flow rate itself is high. Therefore, the combustion system 100 according to this embodiment supplies liquid ammonia to the combustor 112 at low flow rates to reduce the possibility of fuel misfire and ensure stable fuel combustion. Furthermore, the combustion system 100 according to this embodiment supplies gaseous ammonia to the combustor 112 at high flow rates to suppress NOx generation. Thus, by supplying liquid ammonia to the combustor 112 at startup, the combustion system 100 according to this embodiment can supply ammonia as fuel to the combustor 112 even without an external supply of thermal energy. Moreover, the combustion system 100 according to this embodiment can suppress NOx generation while stably burning ammonia without using any fuel other than ammonia, from startup to rated operation.
[0075] Furthermore, when transitioning from a first state in which only gaseous ammonia is supplied to the combustor 112 to a second state in which only liquid ammonia is supplied to the combustor 112, or when transitioning from a second state in which only liquid ammonia is supplied to the combustor 112 to a first state in which only gaseous ammonia is supplied to the combustor 112, a sudden change in the phase of the ammonia supplied to the combustor 112 may impair the combustion stability of the ammonia. Therefore, the line switching device 140 of the combustion system 100 according to this embodiment switches the lines connected to the combustor 112 to the liquid ammonia line 120 and the gaseous ammonia line 130. As a result, the combustion system 100 according to this embodiment can supply both gaseous and liquid ammonia to the combustor 112 simultaneously. Consequently, the combustion system 100 according to this embodiment can change the ammonia supply state to a third state during the transition from the first state to the second state, or during the transition from the second state to the first state. As a result, the combustion system 100 according to this embodiment can ensure the combustion stability of ammonia during the transition from the first state to the second state and during the transition from the second state to the first state.
[0076] Furthermore, the liquid ammonia line 120 of the combustion system 100 according to this embodiment includes a heater 122. This allows the liquid ammonia line 120 according to this embodiment to supply high-temperature liquid ammonia to the combustor 112. Therefore, the combustion system 100 according to this embodiment can improve the ignition of liquid ammonia in the combustor 112 and further suppress misfires, etc. As a result, the combustion system 100 according to this embodiment can further improve the combustion stability of ammonia in the combustor 112. Therefore, the combustion system 100 according to this embodiment can further suppress the generation of NOx in the combustor 112.
[0077] Furthermore, as described above, in this embodiment, the ammonia supplied from the heater 122 of the liquid ammonia line 120 is in liquid form. This avoids the situation in which a two-phase flow of gaseous ammonia and liquid ammonia is supplied to the combustor 112. Therefore, the heater 122 according to this embodiment can further suppress the decrease in the combustion stability of ammonia in the combustor 112.
[0078] The heater 122 includes a first heat exchanger 122a in which heat exchange takes place between a heat transfer medium supplied from a heat source and liquid ammonia flowing through a liquid ammonia line 120, and may further include a heat source switching device 210 that switches the heat transfer medium supply source between a plurality of heat sources with different temperatures.
[0079] As a result, the heat source switching device 210 according to this embodiment can suitably control the temperature of the liquid ammonia heated by the heater 122.
[0080] The heat source switching device 210 may switch the heat transfer medium supply source according to the temperature of the liquid ammonia discharged from the first heat exchanger 122a of the heater 122.
[0081] As a result, the heat source switching device 210 according to this embodiment can more effectively control the temperature of the liquid ammonia heated by the heater 122.
[0082] The heat source switching device 210 may switch the heat transfer medium supply source according to the concentration of NOx contained in the exhaust gas discharged from the combustor 112.
[0083] As a result, the heat source switching device 210 according to this embodiment can suitably control the concentration of NOx contained in the exhaust gas generated in the combustor 112.
[0084] The heat source switching device 210 may switch the heat transfer medium supply source so that the temperature of the heat transfer medium sent to the heater 122 gradually increases.
[0085] As a result, the heat source switching device 210 according to this embodiment can further improve the ignition of liquid ammonia in the combustor 112 and further suppress misfires, etc. As a result, the combustion system 100 according to this embodiment can further improve the combustion stability of ammonia in the combustor 112. Therefore, the combustion system 100 according to this embodiment can further suppress the generation of NOx in the combustor 112.
[0086] The water line 170 includes a first water line 172 that supplies steam from the boiler 160 to the steam turbine 180, and multiple heat sources may also include the first water line 172.
[0087] As a result, the heat source switching device 210 according to this embodiment can suitably raise the temperature of the liquid ammonia in the heater 122.
[0088] The vaporizer 132 includes a second heat exchanger 132a in which heat exchange takes place between steam flowing through the first water line 172 and liquid ammonia flowing through the gaseous ammonia line 130. The multiple heat sources may include the part of the first water line 172 upstream of the second heat exchanger 132a and the part of the first water line 172 downstream of the second heat exchanger 132a.
[0089] As a result, the vaporizer 132 according to this embodiment can suitably vaporize liquid ammonia. Furthermore, the heat source switching device 210 can suitably raise the temperature of the liquid ammonia in the heater 122.
[0090] The water line 170 includes a second water line 174 that supplies water from the steam turbine 180 to the boiler 160, and multiple heat sources may also include the second water line 174.
[0091] As a result, the heat source switching device 210 according to this embodiment can suitably raise the temperature of the liquid ammonia in the heater 122.
[0092] While embodiments of this disclosure have been described above with reference to the attached drawings, it goes without saying that this disclosure is not limited to such embodiments. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of this disclosure.
[0093] For example, in the above embodiment, the case in which the heater 122 includes a first heat exchanger 122a was given as an example. However, the heater 122 does not have to include the first heat exchanger 122a as long as it can heat liquid ammonia. For example, the heater 122 may include an electric heater.
[0094] Furthermore, in the above embodiment, an example was given in which the combustion system 100 is equipped with a heat source switching device 210. However, the heat source switching device 210 is not an essential component.
[0095] Furthermore, in the above embodiment, an example was given in which the heat source switching device 210 switches the heat transfer medium supply source according to the temperature of the liquid ammonia discharged from the first heat exchanger 122a of the heater 122. However, the heat source switching device 210 may also switch the heat transfer medium supply source based on a predetermined switching time, for example.
[0096] Furthermore, in the above embodiment, an example was given in which the heat source switching device 210 switches the heat transfer medium supply source according to the concentration of NOx contained in the exhaust gas discharged from the combustor 112. However, the heat source switching device 210 may also switch the heat transfer medium supply source based on a predetermined switching time, for example.
[0097] Furthermore, in the above embodiment, an example was given in which the heat source switching device 210 switches the heat medium supply source so that the temperature of the heat medium sent to the heater 122 gradually increases. However, the heat source switching device 210 may also switch the heat medium supply source so that the temperature of the heat medium sent to the heater 122 gradually decreases.
[0098] Furthermore, in the above embodiment, the example given was that the combustor 112 is installed in a gas turbine 110. However, the combustor 112 is applicable to boiler plants, gas engine plants, industrial furnaces, and heat exchange reactors.
[0099] Furthermore, in the above embodiment, an example was given in which the heat source for the heat transfer medium sent to the heater 122 (first heat exchanger 122a) includes the upstream side of the first water line 172 of the vaporizer 132a, the downstream side of the first water line 172 of the first water line 172 of the second heat exchanger 132a, and the second water line 174. However, the heat source for the heat transfer medium sent to the heater 122 is not limited to these. For example, the heat source for the heat transfer medium sent to the heater 122 may include the steam from the outlet of the steam turbine 180 and the water in the condenser 174a from the water line 170. With such a configuration, the temperature of the liquid ammonia can be suitably raised in the heater 122.
[0100] Furthermore, in addition to the water line 170, or instead, a heat source other than the water line 170 may be included as a heat source for the heat transfer medium sent to the heater 122. Examples of heat sources other than the water line 170 include the water flow path in the boiler 160, the exhaust gas flow path in the boiler 160, the reheat cycle, seawater, industrial water, tap water, outside air, and the steam flow path of the plant where the combustion system 100 is installed. With such a configuration, the temperature of the liquid ammonia can be suitably raised in the heater 122.
[0101] Furthermore, an intermediate heat exchanger may be provided to exchange heat between a heat source other than the water line 170 and a heat transfer medium, and the heat transfer medium that has undergone heat exchange by the intermediate heat exchanger may be sent to the heater 122. For example, if a highly corrosive heat source such as seawater is used as the heat source other than the water line 170, and a heat transfer medium less corrosive than the heat source, such as industrial water, is used as the heat transfer medium, the scope of corrosion countermeasures can be reduced by providing an intermediate heat exchanger.
[0102] Furthermore, in the above embodiment, steam flowing through the first water line 172 was given as an example of the heat transfer medium sent to the vaporizer 132 (second heat exchanger 132a). However, the heat transfer medium sent to the second heat exchanger 132a of the vaporizer 132 is not limited to this. For example, it may be steam or water flowing through the water line 170 other than the first water line 172, water flowing inside the boiler 160, exhaust gas flowing inside the boiler 160, steam from the reheat cycle (for example, low-temperature reheat steam produced by reheating the steam at the outlet of the steam turbine 180 in the boiler 160), water from the reheat cycle (hot water produced from low-temperature reheat steam), seawater, industrial water, tap water, outside air, steam from the plant where the combustion system 100 is installed, etc. Alternatively, the liquid ammonia flow path of the second heat exchanger 132a of the vaporizer 132 may be installed inside the boiler 160, and the liquid ammonia may be directly heat exchanged with the exhaust gas flowing inside the boiler 160.
[0103] Furthermore, an intermediate heat exchanger may be provided to exchange heat between a heat source other than the water line 170 and the heat transfer medium, and the heat transfer medium that has undergone heat exchange by the intermediate heat exchanger may be sent to the vaporizer 132. For example, if a highly corrosive heat source such as seawater is used as the heat source other than the water line 170, and a heat transfer medium less corrosive than the heat source, such as industrial water, is used as the heat transfer medium, the scope of corrosion countermeasures can be reduced by providing an intermediate heat exchanger.
[0104] Furthermore, a superheater for superheating gaseous ammonia may be provided downstream of the vaporizer 132 in the gaseous ammonia line 130.
[0105] Furthermore, in the above embodiment, an example was given in which the combustion system 100 includes a flow control valve 106, a pump 124, and a compressor 134. However, the combustion system 100 does not necessarily have to include the flow control valve 106, the pump 124, and the compressor 134. This reduces the equipment manufacturing cost of the combustion system 100. In this case, the switching valves 140l and 140g of the line switching device 140 also perform the function of the flow control valve 106. Also, the main pump 104 performs the functions of the pump 124 and the compressor 134.
[0106] Furthermore, in the above embodiment, as explained with reference to Figure 3, an example was given in which the α[%] flow rate is maintained for a predetermined time or longer when transitioning from a low flow rate to an α[%] flow rate and then to a high flow rate, and when transitioning from a high flow rate to an α[%] flow rate and then to a low flow rate. However, it is not necessary for the α[%] flow rate to be maintained for a predetermined time or longer during this transition.
[0107] Figure 5 is a graph showing the change in ammonia flow rate [%] over time in a modified example. In Figure 5, the vertical axis represents ammonia flow rate [%], and the horizontal axis represents time. The solid line in Figure 5 shows the change in total ammonia flow rate, the dashed line shows the change in liquid ammonia flow rate, and the dotted line shows the change in gaseous ammonia flow rate.
[0108] As shown in Figure 5, β[%] is defined as the total ammonia flow rate [%] that is greater than α[%] and less than 100[%]. Furthermore, it is assumed that the ammonia supply to the gas turbine 110 increases linearly over time from startup until rated operation. Therefore, it is assumed that the ammonia supply to the gas turbine 110 also increases linearly over time from the α[%] flow rate to the β[%] flow rate during the process from startup to rated operation.
[0109] In the modified example, the control device 250 selects the second state when the total ammonia flow rate [%] is less than α [%], the first state when the total ammonia flow rate [%] is greater than β [%], and the third state when the total ammonia flow rate [%] is greater than or equal to α [%] and less than or equal to β [%].
[0110] When transitioning from a low flow rate to a high flow rate, in the third state selected when the total ammonia flow rate [%] is α [%] or greater and β [%] or less, the switching valve 140l of the line switching device 140 is gradually closed over time, and the flow rate of liquid ammonia supplied to the combustor 112 gradually decreases over time. On the other hand, the switching valve 140g of the line switching device 140 is gradually opened over time, and the flow rate of gaseous ammonia supplied to the combustor 112 gradually increases over time. Also, when transitioning from a high flow rate to a low flow rate, in the third state selected when the total ammonia flow rate [%] is α [%] or greater and β [%] or less, the switching valve 140g of the line switching device 140 is gradually closed over time, and the flow rate of gaseous ammonia supplied to the combustor 112 gradually decreases over time. Meanwhile, the switching valve 140l of the line switching device 140 gradually opens over time, and the flow rate of liquid ammonia supplied to the combustor 112 gradually increases over time.
[0111] This disclosure can promote the use of ammonia, which leads to a reduction in CO2 emissions, and thus can contribute, for example, to Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable and modern energy," and Goal 13, "Take urgent action to combat climate change and its impacts." [Explanation of Symbols]
[0112] 100 Combustion Systems 110 Gas Turbine 112 Combustor 120 Liquid Ammonia Line 122 Warmer 122a 1st heat exchanger 130 Ammonia gas line 132 Vaporizer 132a 2nd heat exchanger 140 Line switching device 160 boilers 170 Water Line 172 Water Line 1 174 Second Water Line 180 Steam Turbine 210 Heat source switching device
Claims
1. A combustion device that burns ammonia, It has a heater for heating liquid ammonia, and a liquid ammonia line connected to the combustor, It has a vaporizer for vaporizing liquid ammonia, and a gaseous ammonia line connected to the combustor, The lines connected to the combustor are the liquid ammonia line, the gaseous ammonia line, and a line switching device that switches between the liquid ammonia line and the gaseous ammonia line. A combustion system equipped with the following features.
2. The heater includes a first heat exchanger in which heat exchange takes place between a heat transfer medium supplied from a heat source and liquid ammonia flowing through the liquid ammonia line. The device further includes a heat source switching device that switches the supply source of the heat transfer medium between a plurality of heat sources with different temperatures. The combustion system according to claim 1.
3. The combustion system according to claim 2, wherein the heat source switching device switches the supply source according to the temperature of the liquid ammonia discharged from the first heat exchanger.
4. The combustion system according to claim 2, wherein the heat source switching device switches the supply source according to the concentration of NOx contained in the exhaust gas discharged from the combustor.
5. The combustion system according to claim 2, wherein the heat source switching device switches the supply source so that the temperature of the heat medium gradually increases.
6. The aforementioned combustor is installed in a gas turbine, The aforementioned combustion system, A boiler connected to the aforementioned gas turbine, A steam turbine connected to the boiler via a water line, Equipped with, The aforementioned multiple heat sources include the water line, The combustion system according to any one of claims 2 to 5.
7. The water line includes a first water line that supplies steam from the boiler to the steam turbine. The plurality of heat sources include the first water line, The combustion system according to claim 6.
8. The vaporizer includes a second heat exchanger in which heat exchange takes place between the steam flowing through the first water line and the liquid ammonia flowing through the gaseous ammonia line. The plurality of heat sources include the part of the first water line upstream of the second heat exchanger and the part of the first water line downstream of the second heat exchanger. The combustion system according to claim 7.
9. The water line includes a second water line that supplies water from the steam turbine to the boiler. The plurality of heat sources include the second water line, The combustion system according to claim 6.
10. The aforementioned combustor is installed in a gas turbine, The aforementioned combustion system, A boiler connected to the aforementioned gas turbine, A steam turbine connected to the boiler via a water line, Equipped with, The aforementioned plurality of heat sources include heat sources other than the water line, The combustion system according to any one of claims 2 to 5.