Ammonia and hydrogen co-firing combustion system that mitigates combustion instability and exhaust gas emissions.

Abstract

This invention provides an ammonia and hydrogen co-combustion system, a carbon-free combustion technology that significantly increases the low reactivity of ammonia and maximizes the reduction of harmful exhaust substances. [Solution] A combustion system comprising a combustion section 200 in which a combustion region is formed where a first fuel gas G1 and a second fuel gas G2 are supplied and burned, and a fuel nozzle section 100 connected to the front end of the combustion section, which supplies the first fuel gas to the combustion section via a plurality of first nozzles and supplies the second fuel gas to the combustion section via a plurality of second nozzles, wherein the fuel nozzle section has the first nozzles and second nozzles partitioned from each other, and the flow rates of the first and second fuel gases are controlled independently.

Description

Technical Field

[0001] The present invention relates to a combustion system using a carbon-free fuel such as hydrogen or ammonia, and more particularly to an ammonia and hydrogen co-combustion system that improves the reactivity of ammonia and reduces nitrogen oxides in the exhaust gas after combustion.

Background Art

[0002] In power generation, in order to effectively reduce carbon emissions, it is essential to expand renewable energy and convert it into clean energy. Gas (gas turbine) power generation is attracting attention as a power generation energy source that can solve the problem of intermittency of renewable energy. Different from other power generation energy sources, a gas turbine can be quickly started up, mainly responsible for the peak load of power demand, and the power generation amount by the gas turbine accounts for more than 30% of the whole, and its proportion is increasing. Furthermore, green hydrogen and ammonia can be produced by utilizing the excessively supplied renewable energy, and when this is used as the fuel of the gas turbine, not only can the utilization rate of idle power be increased, but it can also greatly contribute to the reduction of carbon emissions. The gas turbine forms a complementary relationship with renewable energy and can solve the instability of power supply due to the intermittent characteristics of renewable energy. In addition, when the hydrogen / ammonia co-combustion / full combustion technology is introduced into the gas turbine, the decarbonization in the power generation part can be accelerated more.

[0003] Ammonia has the property of being easily condensed under relatively low temperature and pressure conditions, is well known as a substance with excellent energy storage properties, contains a large amount of hydrogen in the fuel molecule, and has been in the spotlight as a medium for economically storing / transporting hydrogen. Furthermore, ammonia, which is a carbon-free fuel, can also be used as a direct fuel for a power generation energy source, and its utilization value is gradually increasing in the process of moving forward to the hydrogen economy era.

[0004] However, ammonia flames have the disadvantage of being extremely unreactive and emitting nitrogen oxides tens to thousands of times more than natural gas. In order to utilize ammonia as an environmentally friendly, carbon-free fuel, the technical challenges associated with ammonia must be effectively resolved first. Against this backdrop, despite the recent surge in research on ammonia combustion, neither industry nor academia has been able to present a clear solution to this problem. Therefore, there is a need to develop carbon-free combustion technologies that can significantly increase ammonia's low reactivity and maximize the reduction of harmful exhaust substances. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention was derived to solve the above-mentioned problems, and aims to provide an ammonia and hydrogen co-combustion system, which is a carbon-free combustion technology that can significantly increase the low reactivity of ammonia and maximize the reduction of harmful exhaust substances. [Means for solving the problem]

[0006] A combustion system according to one embodiment of the present invention includes a combustion section in which a combustion region is formed where a first fuel gas and a second fuel gas are supplied and burned, and a fuel nozzle section connected to the front end of the combustion section, which supplies the first fuel gas to the combustion section via a plurality of first nozzles and supplies the second fuel gas to the combustion section via a plurality of second nozzles, wherein the first nozzle and the second nozzle of the fuel nozzle section are partitioned from each other and the flow rates of the first and second fuel gases are controlled independently.

[0007] Furthermore, the first fuel gas is either a mixture of ammonia and air or a mixture of hydrogen and air, and the second fuel gas is the other of the mixture of ammonia and air or a mixture of hydrogen and air.

[0008] Furthermore, the rear end of the fuel nozzle section is provided with a dump section on which the first and second nozzles are formed. The dump section is divided into an inner region formed at the radial center and an outer region formed on the radial outer periphery of the inner region. The first nozzle is located in the inner region, and the second nozzle is located in the outer region.

[0009] Furthermore, the first nozzle is supplied with a first fuel gas, which is a mixture of ammonia and air, and the second nozzle is supplied with a second fuel gas, which is a mixture of hydrogen and air.

[0010] Furthermore, the first fuel gas is supplied to the first nozzle under enriched conditions with an equivalent ratio of 1 or more, and the second fuel gas is supplied to the second nozzle under lean conditions with an equivalent ratio of less than 1.

[0011] Furthermore, the combustion system further includes a sampling unit for collecting exhaust gas discharged from the combustion unit, and an analysis unit for analyzing the components of the exhaust gas collected by the sampling unit.

[0012] Furthermore, the combustion system further includes a control unit that controls the flow rate and equivalent ratio of the first and second fuel gases when the nitrogen oxides analyzed by the analysis unit are above a predetermined value.

[0013] Furthermore, the control unit senses the components of the exhaust gas in real time or at specific intervals and provides feedback on the hydrogen mole fraction or supply amount of the additional fuel gas.

[0014] Furthermore, the fuel nozzle section includes a first housing for receiving the first fuel gas and transmitting it to a plurality of first nozzles, a second housing for receiving the second fuel gas and transmitting it to a plurality of second nozzles, a plurality of first transfer pipes connecting a plurality of first outlets formed in the first housing to the plurality of first nozzles, and a plurality of second transfer pipes connecting a plurality of second outlets formed in the second housing to the plurality of second nozzles.

[0015] Furthermore, the first housing is cylindrical in shape, with a first inlet at its front end for receiving the first fuel gas and a plurality of first outlets at its rear end for discharging the first fuel gas. The second housing is ring-shaped, with the first housing connected to its center so as to pass through it, and has a second inlet on its side for receiving the second fuel gas and a plurality of second outlets at its rear end for discharging the second fuel gas.

[0016] Furthermore, multiple first transfer pipes are spaced apart at the radial center of the first fuel nozzle section, and multiple second transfer pipes are spaced apart around the radial outer circumference so as to surround the first transfer pipes.

[0017] Furthermore, the hydrogen flame produced by the second fuel gas injected from the second nozzle is configured to envelop the ammonia flame produced by the first fuel gas injected from the first nozzle. [Effects of the Invention]

[0018] The ammonia and hydrogen co-firing combustion system of the present invention, configured as described above, has the effect of improving flame stability in ammonia / hydrogen co-firing environments, minimizing nitrogen oxide emissions, and preventing environmental pollution.

[0019] Furthermore, while the formation of an ammonia / air flame under fuel-rich conditions inevitably results in extremely high levels of unburned ammonia and hydrogen production, the re-ignition of ammonia and hydrogen due to the presence of an adjacent hydrogen flame allows for the maintenance of high combustion efficiency.

[0020] Furthermore, it has the effect of naturally inducing a breakdown of flame symmetry in the radial direction (width direction) of the combustion system, thereby reducing combustion oscillations. [Brief explanation of the drawing]

[0021] [Figure 1] This is a side perspective view of a combustion system according to one embodiment of the present invention. [Figure 2]Perspective view of a fuel nozzle section according to an embodiment of the present invention. [Figure 3] Front-end cross-sectional view showing the combustion gas flow path of the fuel nozzle section according to an embodiment of the present invention. [Figure 4] Rear view showing the damper section of the fuel nozzle section of the present invention. [Figure 5] Graph showing the exhaust emission characteristics of an ammonia / hydrogen / air flame. [Figure 6] Graph showing the exhaust emission characteristics of an ammonia / hydrogen / air flame. [Figure 7] Graph showing the internal / external ammonia co-combustion rate and equivalence ratio according to experimental conditions. [Figure 8] Graph showing the internal / external ammonia co-combustion rate and equivalence ratio according to experimental conditions. [Figure 9] Graph showing the combustion vibration and the measurement results of the concentration of major emission substances according to experimental conditions.

Mode for Carrying Out the Invention

[0022] Hereinafter, an embodiment of the present invention as described above will be described in detail with reference to the drawings.

[0023] In FIG. 1, a side perspective view of a combustion system 1000 according to an embodiment of the present invention is illustrated.

[0024] As illustrated in FIG. 1, the combustion system 1000 can be configured to include a fuel nozzle section 100, a combustion section 200, a flame tube 300, a sampling section 500, and a gas analysis section (not shown). A combustion section 200 is formed at the rear end of the fuel nozzle section 100, and a flame tube 300 is provided at the rear end of the combustion section 200. The fuel nozzle section 100 and the combustion section 200 are formed independently and are configured to be bonded and sealed with room temperature vulcanizing (RTV) silicone. The combustion section 200 and the flame tube 300 are formed independently and can be bolted together.

[0025] The fuel nozzle section 100 is configured to receive a first fuel gas G1 and a second fuel gas G2 and supply them to the combustion section 200. The performance of the combustion system 1000 can be determined according to the diameter of the rear end 120. Since the front end 110 has a manifold-shaped structure built inside, the diameter of the front end 110 can be made larger than the diameter of the rear end 120 for ease of manufacturing.

[0026] A choked orifice 121 is provided on the front end side of the rear end 120. The choked orifice 121 consists of a cylindrical stainless steel block with a width of about 10 mm and has three holes, and serves as an upstream acoustic boundary.

[0027] Furthermore, a swirler 122 is provided on the rear end side of the rear end portion 120. The swirler 122 consists of a number of vanes, each 10 mm wide and having a swirl angle of 40 to 50 degrees. The swirler 122 can be configured to apply swirl to the flow of the first and second fuel gases G1 and G2 to improve flame stability.

[0028] The combustion section 200 is located at the rear end of the fuel nozzle section 100 and is configured to burn upon receiving the supply of first and second fuel gases G1 and G2 supplied through the fuel nozzle section 100. The combustion section 200 has a combustion region 201 formed inside, and the front end of the combustion region 201 can communicate with the rear end of the fuel nozzle section 100.

[0029] The first and second fuel gases G1 and G2 flowing through the combustion section 200 are ignited and burned by an igniter 175 (see Figure 4) provided at the rear end of the fuel nozzle section 100, generating an ammonia flame and a hydrogen flame, respectively.

[0030] Thermal energy is generated through ammonia and hydrogen flames produced in the combustion region 201, and the combustion gases produced by the flames are supplied to a flame tube 300 connected to the rear end of the combustion section 200, where they are cooled by heat exchange with cooling air or a cooling fluid before being discharged as exhaust gas G3.

[0031] Here, the fuel nozzle section 100 has the following configuration to supply the first fuel gas G1 and the second fuel gas G2 to the combustion chamber 200 independently.

[0032] Figure 2 shows a perspective view of the fuel nozzle section 100 according to one embodiment of the present invention, and Figure 3 shows a cross-sectional view of the front end portion 110 of the fuel nozzle section 100 showing the combustion gas flow path according to one embodiment of the present invention.

[0033] Referring to Figures 2 and 3, the system includes a number of first transfer pipes 130 for transferring the first fuel gas G1 to the combustion chamber 200, and a number of second transfer pipes 140 for transferring the second fuel gas G2 to the combustion chamber 200.

[0034] More specifically, the fuel nozzle section 100 is divided into a front end 110 and a rear end 120, and the front end 110 can consist of a configuration in which a first housing 150 for transmitting the first fuel gas G1 to a plurality of first transfer pipes 130 and a second housing 160 for transmitting the second fuel gas G2 to a plurality of second transfer pipes 140 are connected. The first housing 150 has a first space S10 formed inside for the flow of the first fuel gas G1, a first inlet 111 for the inflow of the first fuel gas G1 is formed on the upstream side of the first space S10, and a plurality of first outlets 115 connected to the first transfer pipes 130 are formed at the rear end. Furthermore, the second housing 160 has a second space S20 formed inside so that the second fuel gas G2 can flow through it, a second inlet 112 formed upstream of the second space S20 for the second fuel gas G2 to flow in, and a number of second outlets 116 connected to the second transfer pipe 140 are formed at the rear end.

[0035] Here, the first housing 150 is positioned at the radially inward center so that the first fuel gas G1 flows radially inward and the second fuel gas G2 flows radially outward, and the second housing 160 is ring-shaped and can be connected so that the first housing 150 passes through its center. Accordingly, the multiple first transfer pipes 130, each connected to the first outlet 115 of the first housing 150, can also be positioned at the radial center, and the multiple second transfer pipes 140, each connected to the second outlet 116 of the second housing 160, can be positioned on the radially outer circumference so as to surround the first transfer pipes 130.

[0036] Injectors may be provided on the first and second transfer pipes and configured to inject the first or second fuel gas into the combustion chamber.

[0037] Figure 4 shows a rear view of the dump section 170 of the fuel nozzle section 100 of the present invention.

[0038] Referring to Figures 1 and 4, a dump section 170 can be formed at the rear end of the fuel nozzle section 100 for injecting the first and second fuel gases G1 and G2 into the combustion section 200. As described above, the fuel nozzle section 100 has the following configuration to supply the first fuel gas G1 and the second fuel gas G2 to the combustion chamber 200 independently.

[0039] The dump section 170 includes a plurality of first nozzles 171 connected to the rear end of the first transfer pipe 130 and a plurality of second nozzles 172 connected to the rear end of the second transfer pipe 140. On the other hand, the dump section 170 includes an inner region A10 communicating with the first inlet 111 and an outer region A20 communicating with the second inlet 112 and formed radially outside the inner region A10, separated from the inner region A10. Therefore, the first nozzles 171 can be positioned on the inner region A10, and the second nozzles 172 can be positioned on the outer region A20. Thus, the first fuel gas G1 is injected into the combustion chamber 200 independently via the inner region A10, and the second fuel gas G2 is injected into the combustion chamber 200 independently via the outer region A20.

[0040] Numerous first nozzles 171 and second nozzles 172 can be spaced apart in the radial and circumferential directions, as shown in the figure. The first nozzles 171 and second nozzles 172 can be arranged in a configuration of 60 nozzles of 6.5 mm in diameter in four concentric circles, with 16 first nozzles 171 positioned at the radial center and 44 second nozzles 172 positioned on the radial outward side. That is, the first nozzles 171 can be positioned in the inner region A10 and the second nozzles 172 in the outer region A20, forming multiple stages in the radial direction.

[0041] Therefore, the system is configured to allow independent control of the flow rates and equivalent ratios of the first fuel gas G1 and the second fuel gas G2 supplied to the inner region A10 and the outer region A20, respectively.

[0042] On the other hand, the first and second fuel gases G1 and G2 are injected independently, and the injection area is divided into an inner region A10 and an outer region A20, so that the flame of the first fuel gas G1 injected through the inner region A10 moves in a manner that is enveloped by the flame of the second fuel gas G2 injected through the outer region A20.

[0043] In particular, the first fuel gas G1, which forms the internal flame, consists of a mixture of ammonia and air, and the second fuel gas G2, which forms the external flame, consists of a mixture of hydrogen and air. This configuration induces a state where the internal ammonia flame is enveloped by the external hydrogen flame, thereby maximizing the stability of the ammonia flame.

[0044] On the other hand, the first fuel gas G1 may be an ammonia / air mixture doped with a small amount of hydrogen. For example, the first fuel gas G1 may be a mixed fuel gas consisting of 90% ammonia and 10% hydrogen by volume.

[0045] Another reason for supplying the first fuel gas G1 and the second fuel gas G2 to the combustion chamber independently to induce the flame is that combustion of ammonia and hydrogen in a separated state is more advantageous than co-combustion in terms of reducing nitrogen oxides.

[0046] Furthermore, the first fuel gas G1 can form a highly enriched equivalent ratio condition, which is higher than the stoichiometric equivalent ratio of 1, while the second fuel gas G2 can form a lean equivalent ratio condition, which is lower than the equivalent ratio of 1. This is because burning ammonia under a highly enriched fuel condition is advantageous in reducing nitrogen oxide emissions, while burning hydrogen under a lean fuel condition is also advantageous in reducing nitrogen oxide emissions.

[0047] As shown in Figure 1, a sampling unit 500 is provided at the front end of the flame tube 300, configured to collect a portion of the exhaust gas G3. The sampling unit 500 may be a standard sampling probe. The exhaust gas G3 collected via the sampling unit 500 is transmitted to an analysis unit (not shown) for analysis and measurement of the gas's components. The analysis unit includes an analyzer and a nitrogen diluent. The analyzer receives the exhaust gas G3 from the sampling unit and analyzes and measures nitrogen oxides, hydrogen, ammonia, and oxygen components. The analyzer may, for example, be equipped with an Ecom J2KN Pro.

[0048] Furthermore, the exhaust gas G3 transmitted to the analyzer can be configured to be diluted with nitrogen using a nitrogen diluent before being supplied to the analyzer.

[0049] The analyzer is configured to provide feedback on the supply amounts and equivalent ratios of the first and second fuel gases G1 and G2, respectively, that minimize nitrogen oxides, based on the component analysis of exhaust gas G3 as described above. For example, it can be configured to measure nitrogen oxides in exhaust gas G3 at a specific time or in real time, and if nitrogen oxides are detected above a certain value, adjust the supply amounts of each fuel gas or the equivalent ratio of each fuel gas to reduce nitrogen oxides.

[0050] Cooling air channels and cooling water channels can be formed on the flame tube 300 to cool the exhaust gas through heat exchange with the exhaust gas.

[0051] Figure 5 shows a graph illustrating the emission characteristics of nitrogen oxides from ammonia / hydrogen / air flames based on the hydrogen co-firing ratio, and Figure 6 shows a graph illustrating the changes in the amount of major exhaust substances generated by equivalent ratio under fixed hydrogen co-firing conditions.

[0052] As illustrated in Figure 5, it can be seen that the reduction effect of nitrogen oxides in flames burned with 100% hydrogen or 100% ammonia is more advantageous than that of mixed combustion. As illustrated in Figure 6, it can be seen that combustion under a fuel-rich condition (equivalent ratio 1.4) is significantly more effective in reducing nitrogen oxide generation than under a lean fuel condition (equivalent ratio 0.6) when mixed with 90% ammonia and 10% hydrogen. Based on these exhaust emission characteristics of ammonia / hydrogen / air flames, the combustion system of the present invention is provided as described above.

[0053] Specifically, to evaluate the applicability of the proposed combustion technique under extreme nitrogen oxide emission conditions, the baseline conditions were selected as a 30 / 70 ammonia / hydrogen co-combustion condition. In the first combustion embodiment, only the fuel flow of hydrogen and ammonia supplied to radially divided internal and external regions was adjusted, inducing the formation of an ammonia flame in the internal region and a hydrogen flame in the external region. This is consistent with the direction of nitrogen oxide reduction shown in the calculation results presented in Figure 5. In the second combustion embodiment, with the flow rates of hydrogen and ammonia supplied to each region fixed, the amount of air supplied (flow) between the internal and external regions was adjusted, creating an equivalence ratio condition higher than a specific equivalence ratio in the internal region, while conversely, inducing an equivalence ratio condition lower than the aforementioned specific equivalence ratio in the external region. In the ammonia flame formed in the internal region, as shown in the results presented in Figure 6, nitrogen oxides decreased significantly as the equivalence ratio increased, indicating a significant effect on reducing nitrogen oxides.

[0054] On the other hand, in the case of a hydrogen total combustion flame in the external region, prior studies have confirmed that nitrogen oxides of 5 ppm or less are generated in the dilute region. Therefore, the second embodiment is configured to further reduce nitrogen oxides in the exhaust gas.

[0055] To confirm that the proposed combustion technique operates normally even under extreme nitrogen oxide emission conditions, the overall ammonia co-combustion ratio was fixed at 30%, and the operating conditions under which the test was conducted are illustrated in Figures 7 and 8. As illustrated in Figures 7 and 8, it can be seen that even though ammonia, which has extremely low reactivity, was immediately used in the hydrogen-based combustion system, the application of the present invention did not result in static instability such as dilute scattering, and furthermore, the flame was stably maintained within a relatively narrow reaction region.

[0056] Figure 9a shows a graph illustrating the measurement results of pressure perturbation amplitudes generated during combustion oscillation, and Figure 9b shows a graph illustrating the concentration measurement results of major exhaust substances.

[0057] Referring to Figure 9a, the X-axis represents the length of the combustor, the Y-axis represents each test condition, and the color of the contour graph represents the dynamic pressure amplitude.

[0058] To more specifically confirm the effectiveness of the staging technique according to the present invention, the experiment was conducted by dividing the staging into two sections.

[0059] High-amplitude combustion oscillations primarily occur when the combustor is long.

[0060] The initial staging was fuel staging, where the air flow rate supplied to the internal / external regions was fixed under UB conditions, and only the hydrogen and ammonia flow rates supplied to the internal / external regions were switched during the test. When the initial staging technique was applied to the baseline condition (UB → F3), it was observed that the amplitude of the pressure perturbation was reduced to half its level. Therefore, combustion oscillations could be reduced, demonstrating the control effect on major exhaust substances.

[0061] The second staging method was air staging, in which, under F3 conditions, the flow rates of hydrogen and ammonia supplied to the inner and outer regions were fixed, and a portion of the air supplied to the inner region was supplied to the outer region for testing. While the effect of this second staging technique on combustion oscillation intensity was minimal, the control effect on major exhaust substances was demonstrated.

[0062] Referring to Figure 9b, the X-axis represents concentration, and the Y-axis represents each test condition (sharing the Y-axis with Figure 9a).

[0063] When all of the proposed staging techniques are applied, nitrogen oxides are reduced by 96% compared to the baseline condition (UB) (7764 → 310 ppm), no unburned ammonia is generated, and the hydrogen concentration at the rear end of the combustor drops sharply to the 130 ppm level (130 ppm is lower than the amount of hydrogen slip generated when hydrogen is completely burned).

[0064] The technical idea of ​​the present invention should not be interpreted as being limited to the above embodiments. Needless to say, the scope of application is diverse, and various modifications can be made at the level of a person skilled in the art without departing from the gist of the invention as claimed. Therefore, such improvements and modifications are within the scope of protection of the present invention, insofar as they are obvious to a person skilled in the art.

Claims

1. A combustion section is formed in which a combustion region is created where a first fuel gas and a second fuel gas are supplied and burned, The system includes a fuel nozzle section connected to the front end of the combustion section, which supplies a first fuel gas to the combustion section via a plurality of first nozzles and a second fuel gas to the combustion section via a plurality of second nozzles. The fuel nozzle section is a combustion system in which the first nozzle and the second nozzle are partitioned from each other, and the flow rates of the first and second fuel gases are controlled independently.

2. The first fuel gas is It is either a mixture of ammonia and air or a mixture of hydrogen and air. The second fuel gas is The combustion system according to claim 1, wherein the mixture is a mixture of ammonia and air, or a mixture of hydrogen and air, or the other of the latter.

3. The rear end of the fuel nozzle section is provided with a dump section in which the first and second nozzles are formed. The aforementioned dumping section is An inner region formed at the radial center, The outer region is formed on the radial outer periphery of the inner region, The combustion system according to claim 2, wherein the first nozzle is located in the inner region and the second nozzle is located in the outer region.

4. The first nozzle is supplied with a first fuel gas, which is a mixture of ammonia and air. The combustion system according to claim 3, wherein a second fuel gas, which is a mixture of hydrogen and air, is supplied to the second nozzle.

5. The first fuel gas is supplied to the first nozzle under conditions of excessive enrichment, with an equivalent ratio of 1 or more. The combustion system according to claim 4, wherein the second fuel gas is supplied to the second nozzle under lean conditions with an equivalent ratio of less than 1.

6. The aforementioned combustion system, A sampling unit for collecting exhaust gas discharged from the combustion unit, The combustion system according to claim 1, further comprising an analysis unit for analyzing the components of exhaust gas collected by the sampling unit.

7. The aforementioned combustion system, The combustion system according to claim 6, further comprising a control unit that controls the flow rate and equivalent ratio of the first and second fuel gases when the nitrogen oxides analyzed by the analysis unit are above a predetermined value.

8. The control unit, The combustion system according to claim 7, which senses the components of the exhaust gas in real time or at specific intervals and provides feedback on the hydrogen mole fraction or supply amount of additional fuel gas.

9. The fuel nozzle section is A first housing for receiving the first fuel gas and transmitting it to a plurality of first nozzles, A second housing for receiving the second fuel gas and transmitting it to a plurality of second nozzles, A plurality of first discharge ports formed in the first housing and a plurality of first transfer pipes connecting each of the plurality of first nozzles, The combustion system according to claim 1, further comprising a plurality of second outlets formed in the second housing and a plurality of second transfer pipes connecting each of the plurality of second nozzles.

10. The first housing is cylindrical in shape, has a first inlet at its front end for receiving the first fuel gas, and has a plurality of first outlets at its rear end for discharging the first fuel gas. The combustion system according to claim 9, wherein the second housing is ring-shaped, the first housing is connected to it so as to pass through its center, a second inlet for receiving the second fuel gas is formed on its side, and a plurality of second outlets for discharging the second fuel gas are formed at its rear end.

11. Multiple first transfer pipes are spaced apart from each other at the radial center of the first fuel nozzle section. The combustion system according to claim 10, wherein a plurality of the second transfer pipes are spaced apart on the radial outer circumference so as to enclose the first transfer pipe.

12. The combustion system according to claim 4, wherein the hydrogen flame produced by the second fuel gas injected from the second nozzle envelops the ammonia flame produced by the first fuel gas injected from the first nozzle.

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