A porous media combustion device for catalytic pyrolytic combustion of ammonia

Abstract

The application provides a porous medium combustion device for catalytic pyrolysis combustion of ammonia, in which ammonia is preheated in a catalytic pyrolysis reactor, and is partially pyrolyzed into nitrogen and hydrogen through a heterogeneous ruthenium-free catalyst, and the mixed gas (NH3, N2 and H2) after pyrolysis is introduced into a porous medium combustor to combust after being fully preheated in a premixing zone; the combustion flue gas is used for preheating of ammonia in the catalytic pyrolysis reactor, the flame propagation speed is improved, the combustion stability of the NH3 / H2 / air mixture is increased, and the flammability limit is improved; the high-temperature flue gas generated by combustion is heat-exchanged through a heat exchanger, on the one hand, energy is externally delivered, and on the other hand, through the coupling structure of the heat exchanger and the catalytic pyrolysis reactor, ammonia is preheated to a temperature range of 300 DEG C-500 DEG C and is used for catalytic pyrolysis of ammonia, without external energy input, and the combustion efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of hydrocarbon fuel combustion devices, specifically relating to a porous media combustion device for ammonia catalytic pyrolysis combustion. Background Technology

[0002] Ammonia (NH3), as a highly efficient and clean chemical energy storage carrier, has gradually gained widespread attention from the international community and was recognized as a renewable energy source by the International Energy Agency in 2017. As a high-hydrogen-content substance, ammonia is an excellent hydrogen carrier; the existing industrial system for ammonia production, storage, and transportation is relatively well-established, providing a carbon-free fuel alternative for industrial heating, power generation, and transportation; furthermore, carbon-free ammonia synthesis technology using renewable energy is relatively mature. In almost all current applications, ammonia has the potential to become a substitute for fossil fuels, forming an "ammonia economy." Therefore, researching efficient and clean ammonia combustion technology, as a highly attractive solution for promoting the use of renewable energy and achieving "dual-carbon goals," has become a research hotspot in the international and domestic combustion fields.

[0003] Despite the aforementioned advantages, ammonia still faces a series of challenges in its practical combustion applications: compared to conventional hydrocarbon fuels, ammonia has a lower calorific value, lower combustion temperature, and poorer ignition performance; ammonia exhibits low laminar flame propagation speed and poor combustion stability; furthermore, as a nitrogen-containing fuel, ammonia has high NO content. x Emissions are a concern. To address the instability of ammonia combustion, many studies have explored blending it with highly reactive fuels (such as methane and hydrogen). However, blending ammonia with other fuels increases the complexity of the combustion system. Furthermore, highly reactive fuels (such as hydrogen) are generally more difficult and risky to transport than ammonia, increasing the difficulty of their application in practical burners.

[0004] Ammonia catalytic pyrolysis is a process that uses a catalyst to decompose ammonia into hydrogen and nitrogen. The reaction products can be used to produce hydrogen fuel or in other chemical processes. However, the high temperatures required for ammonia pyrolysis and the use of catalysts significantly increase equipment costs and energy consumption. Traditional ammonia catalytic pyrolysis methods commonly employ iron-based, nickel-based, and ruthenium-based catalysts, but each has its limitations: iron-based catalysts have abundant raw material sources and low costs, but their activity is lower compared to the other two types; nickel-based catalysts offer moderate cost and activity, but require relatively high reaction temperatures; ruthenium-based catalysts currently possess the highest activity for ammonia decomposition, but the high cost of ruthenium makes them uneconomical and unsustainable. Therefore, ammonia catalytic pyrolysis still faces risks and challenges in practical applications.

[0005] Based on the above analysis, the existing technologies have the following problems and defects: (1) Low laminar flame propagation speed and weak ignition characteristics lead to poor combustion stability of ammonia; the low calorific value of ammonia results in a low combustion temperature, which easily leads to the risk of ammonia leakage. (2) Blending ammonia with highly reactive fuels increases application costs and the complexity of the combustion system, increasing the difficulty of practical application. (3) Ammonia pyrolysis catalysts suffer from insufficient activity, high cost, and high reaction temperature, requiring the development of new catalysts that are more active, economical, and sustainable. Therefore, a new porous media combustion device for ammonia catalytic pyrolysis combustion needs to be proposed to solve the above technical problems. Summary of the Invention

[0006] This invention provides a porous media combustion device for ammonia catalytic pyrolysis combustion, which can solve the risks and challenges of existing ammonia catalytic pyrolysis in practical applications.

[0007] To solve the above problems, the technical solution provided by the present invention is as follows:

[0008] This invention provides a porous media combustion device for catalytic pyrolysis combustion of ammonia, including a gas delivery assembly, a premixing chamber (3), a porous media burner, an ignition device (6), a thermocouple (7), a heat exchange chamber (8), a catalytic pyrolysis reactor (9), a hot water pipe (10), and a smoke hood (11).

[0009] The gas delivery assembly includes an air inlet (1) and an ammonia inlet (2); the premixing chamber (3) includes a porous foam block; the porous media burner includes an upstream porous media burner (4) and a downstream porous media burner (5); an ignition device (6) is also provided between the upstream porous media burner (4) and the downstream porous media burner (5); the catalytic pyrolysis reactor (9) includes a heat exchange structure and a catalyst carrier.

[0010] The inlet of the catalytic pyrolysis reactor (9) is connected to the ammonia inlet (2); the inlet of the premixing chamber (3) is connected to the outlet of the catalytic pyrolysis reactor (9) and the air inlet (1); the upper side of the premixing chamber (3) is connected to the porous media burner; the outlet of the porous media burner is connected to the heat exchange chamber (8); the heat exchange water pipe (10) is arranged around the heat exchange chamber (8) for heat exchange;

[0011] The heat exchange chamber (8) is coupled to the catalytic pyrolysis reactor (9). When ammonia is preheated in the catalytic pyrolysis reactor (9), it is partially catalytically pyrolyzed into N2 and H2. After being fully premixed with air in the premixing chamber (3), it enters the porous medium burner for combustion. The combustion flue gas enters the heat exchange chamber (8) to transport energy to the outside, and at the same time, it is used to preheat the ammonia inside the catalytic pyrolysis reactor (9) coupled to the heat exchange chamber (8).

[0012] Several thermocouples (7) are installed inside the porous media burner and at the catalytic pyrolysis reactor (9) to measure the temperature at different heights in the combustion chamber and the temperature of the catalytic pyrolysis reactor (9). A smoke hood (11) is also installed on the top of the heat exchange chamber (8). The smoke hood (11) is used to collect the flue gas generated by combustion and measure the flue gas composition through a flue gas analyzer to further investigate the combustion state of ammonia.

[0013] According to an optional embodiment of the present invention, the catalyst of the catalytic pyrolysis reactor (9) is a novel isomer ruthenium-free catalyst. The catalyst is composed of CoNi alloy nanoparticles dispersed on a support of mixed oxides magnesium, cesium and strontium, and modified with K additive, represented as K-CoNiO-MgOCeO2-SrO; the catalyst support includes Al2O3 spherical particles with a particle size of 3 mm-5 mm.

[0014] According to an optional embodiment of the present invention, the upstream (4) and downstream (5) of the porous media burner are both ceramic foam blocks with a thickness of 50 mm and a diameter of 100 mm.

[0015] According to an optional embodiment of the present invention, the upstream (4) of the porous media burner is made of yttrium-stabilized zirconium oxide material, and the pore density of the upstream (4) of the porous media burner is 20 PPI, which is used as a backfire prevention device;

[0016] The downstream section (5) of the porous media burner is made of silicon carbide material and has a pore density of 10 PPI, serving as the combustion zone.

[0017] According to an optional embodiment of the present invention, thermocouples 1-5 (7) are inserted into the porous medium burner and in direct contact with the ceramic substrate to measure the temperature at different heights of the combustion chamber; thermocouple 6 (7) is placed at the coupling point between the catalytic pyrolysis reactor (8) and the heat exchange chamber (8) to measure the temperature of the catalytic pyrolysis reactor (9).

[0018] According to an optional embodiment of the present invention, thermocouple No. 6 (7) arranged inside the porous medium burner is inserted 10 mm into the interior of the porous medium burner.

[0019] According to an optional embodiment of the present invention, the premixing chamber (3) and the protective layer outside the porous medium burner are both made of quartz glass and are used to observe the combustion flame, detect the combustion status and combustion stability.

[0020] According to an optional embodiment of the present invention, both the porous medium burner and the heat exchange chamber (8) are provided with a heat insulation structure around their structures, which is used to reduce heat loss from the surrounding walls.

[0021] According to an optional embodiment of the present invention, the hot water exchange pipe (10) includes a front section structure and a rear section structure disposed on both sides of the catalytic pyrolysis reactor (9). The front section structure and the rear section structure of the hot water exchange pipe (10) are used to adjust the heat exchange of the catalytic pyrolysis reactor (9) and thereby regulate the temperature of the catalytic pyrolysis reactor (9).

[0022] According to an optional embodiment of the present invention, the rear section of the hot water exchange pipe (10) is also used for countercurrent heat exchange with the flue gas.

[0023] Beneficial Effects: This invention provides a porous media combustion device for the catalytic pyrolysis combustion of ammonia. The ammonia is preheated in the catalytic pyrolysis reactor and partially pyrolyzed into nitrogen and hydrogen by an isomer-based ruthenium-free catalyst. The resulting pyrolysis mixture (NH3, N2, and H2) is fully preheated with air in a premixing zone before being introduced into the porous media burner for combustion. Because the combustion flue gas is used to preheat the ammonia in the catalytic pyrolysis reactor, the flame propagation speed is increased, enhancing the combustion stability of the NH3 / H2 / air mixture and improving its flammability limit. The high-temperature flue gas generated during combustion is heat-exchanged through a heat exchanger, which, on the one hand, transfers energy externally, and on the other hand, through the coupling structure between the heat exchanger and the catalytic pyrolysis reactor, preheats the ammonia to a temperature range of 300℃-500℃ for catalytic pyrolysis, eliminating the need for external energy input and improving combustion efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a schematic diagram of a porous media combustion device for catalytic pyrolysis combustion of ammonia, provided as an embodiment of this application. In the figure, 1 is the air inlet, 2 is the ammonia inlet, 3 is the premixing chamber, 4 is the upstream of the porous media burner, 5 is the downstream of the porous media burner, 6 is the ignition device, 7 is the thermocouple, 8 is the heat exchange chamber, 9 is the catalytic pyrolysis reactor, 10 is the hot water pipe, and 11 is the smoke hood. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] In the description of this application, it should be understood that the terms "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," and "horizontal," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, " / " means "or." In the figures, structurally similar units are represented by the same reference numerals, and dashed lines in the figures indicate units that do not exist in the structure, merely illustrating the shape and position of the structure. Reference numbers and / or reference letters may be repeated in different examples in this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various implementations and / or settings discussed.

[0028] like Figure 1 The diagram shown is a schematic representation of a porous media combustion device for ammonia catalytic pyrolysis combustion, provided in this application embodiment. This porous media combustion device for ammonia catalytic pyrolysis combustion includes a gas delivery assembly, a premixing chamber 3, a porous media burner, an ignition device 6, a thermocouple 7, a heat exchange chamber 8, a catalytic pyrolysis reactor 9, a hot water exchange pipe 10, and a smoke hood 11.

[0029] The premixed gas delivery assembly includes an air inlet 1 and an ammonia inlet 2, with the inlet of the catalytic pyrolysis reactor 9 connected to the ammonia inlet 2. The premixing chamber 3 includes porous foam blocks to promote thorough premixing of fuel gas and air. The porous media burner includes an upstream porous media burner 4 and a downstream porous media burner 5, both of which are ceramic foam blocks with a thickness of 50 mm and a diameter of 100 mm. The upstream section 4 of the porous media burner is made of yttrium-stabilized zirconia material with a pore density of 20 PPI. The upstream ceramic structure has porous thermal conduction channels, which can promote heat transfer and prevent flashback, serving as a flashback prevention device. The downstream section 5 of the porous media burner is made of silicon carbide material with a pore density of 10 PPI. Internal thermal recirculation occurs in the downstream solid porous matrix through thermal radiation and thermal conduction, transferring some of the combustion heat to the porous media structure upstream of the burner, further preheating the reactants, increasing the flame propagation speed, increasing the combustion stability of the NH3 / H2 / air mixture, and improving the flammability limit, serving as the combustion zone.

[0030] In this embodiment, an ignition device 6 is also provided between the upstream 4 and downstream 5 of the porous media burner for igniting the premixed gas. The inlet of the premixing chamber 3 is connected to the outlet of the catalytic pyrolysis reactor 9 and the air inlet 1. The upper side of the premixing chamber 3 is connected to the porous media burner. The outlet of the porous media burner is connected to the heat exchange chamber 8. The heat exchange water pipe 10 is arranged around the heat exchange chamber 8 for heat exchange.

[0031] The heat exchange chamber 8 is coupled to the catalytic pyrolysis reactor 9. After ammonia is preheated in the catalytic pyrolysis reactor 9, it is partially catalytically pyrolyzed into N2 and H2. After being fully premixed with air in the premixing chamber 3, it enters the porous media burner for combustion. The combustion flue gas enters the heat exchange chamber 8 to deliver energy to the outside. At the same time, it is used to preheat the ammonia inside the catalytic pyrolysis reactor 9 coupled with the heat exchange chamber 8. By adjusting the heat exchange capacity of the heat exchange chamber before coupling the catalytic pyrolysis reactor 9, the temperature of the catalytic pyrolysis reactor 9 can be controlled according to the optimal catalytic pyrolysis conditions of ammonia.

[0032] Several thermocouples 7 are installed inside the porous media burner and at the catalytic pyrolysis reactor 9 to measure the temperature at different heights in the combustion chamber and the temperature of the catalytic pyrolysis reactor. Specifically, several thermocouples 7 are installed inside the porous media burner to obtain the burner temperature distribution. Thermocouples 7 1-5 are inserted into the porous media burner and in direct contact with the ceramic substrate to measure the temperature at different heights in the combustion chamber. Thermocouple 7 6 is placed at the coupling point between the catalytic pyrolysis reactor 9 and the heat exchange chamber 8 to measure the temperature of the catalytic pyrolysis reactor. Preferably, the thermocouples 7 arranged inside the porous media burner are inserted 10 mm into the interior of the burner.

[0033] A smoke hood 11 is also installed at the top of the heat exchange chamber 8. The smoke hood 11 is used to collect the flue gas generated by combustion and measure the flue gas composition through a flue gas analyzer to further investigate the combustion state of ammonia. The protective layer of the premixing chamber 3 and the outside of the porous media burner is made of quartz glass and is used to observe the combustion flame, detect the combustion status and combustion stability.

[0034] Heat exchange chamber 8 is coupled to catalytic pyrolysis reactor 9. Ammonia gas, after being introduced into catalytic pyrolysis reactor 9, can be preheated to 300℃-500℃ by the combustion flue gas, promoting partial pyrolysis of ammonia into nitrogen and hydrogen. This improves combustion stability, broadens the stable combustion range at the bottom, and increases combustion efficiency. Simultaneously, due to the partial pyrolysis of ammonia, the absolute flow rate of ammonia decreases, reducing NO content in the combustion flue gas. x And NH3 emissions. In this embodiment, ammonia has a low calorific value and a narrow flammability limit range. Catalytic pyrolysis reactor 9 catalytically pyrolyzes part of the ammonia into N2 and H2. The mixed combustion of ammonia and hydrogen can enhance the flame propagation speed, significantly improve combustion stability, help broaden the stable flammability equivalence ratio range of the bottom fuel, and help enhance the flammability limit of ammonia, thus improving combustion stability. Catalytic pyrolysis reduces the absolute flow rate of ammonia, which helps reduce NO emissions. x And NH3 emissions.

[0035] The porous media burner has a large number of interconnected pores inside, through which fuel and oxygen can enter the combustion chamber uniformly and be fully mixed. Furthermore, the flow of gas within the porous media is hindered, slowing the flow rate and making the combustion process more stable. The internal surface area of ​​the porous media is much larger than the actual geometric surface area, which increases the contact area between fuel and oxygen, facilitating mixing and combustion.

[0036] A heat exchange chamber 8 is located on the upper side of the porous media burner. The hot water pipes 10 surrounding the heat exchange chamber 8 exchange heat with the flue gas in a counter-current manner, while simultaneously preventing localized high temperatures within the combustion chamber. Both the porous media burner and the heat exchange chamber 8 are surrounded by insulation structures to reduce heat loss from the surrounding walls. A catalytic pyrolysis reactor 9 is coupled to the heat exchange chamber 8. The high-temperature flue gas generated during combustion passes through this coupling structure, preheating the ammonia gas to a temperature range of 300℃-500℃ for catalytic pyrolysis of the ammonia. This eliminates the need for external energy input and improves combustion efficiency.

[0037] The catalytic pyrolysis reactor 9 includes a heat exchange structure and a catalyst support; the catalyst support includes Al2O3 spherical particles with a particle size of 3mm-5mm. The Al2O3 spherical particles have better hydrodynamic performance and mechanical strength; the spherical catalyst support has a high specific surface area and porosity, which can increase the catalyst loading, thereby improving the catalyst activity and stability.

[0038] The catalyst used in catalytic pyrolysis reactor 9 is a novel isomeric ruthenium-free catalyst. This catalyst consists of CoNi alloy nanoparticles dispersed on a mixed oxide (including magnesium, cesium, and strontium) support and modified with a K-modifier, denoted as K-CoNiO2-MgOCeO2-SrO. It exhibits a synergistic effect, significantly improving the catalytic activity and stability of the catalyst for ammonia decomposition, thus balancing economic benefits and catalytic performance. The catalyst is supported on an Al2O3 support; alumina possesses high thermal stability and chemical inertness, enabling it to withstand high operating temperatures and redox reactions in the catalytic reaction.

[0039] The heat exchanger pipe 10 includes a front section and a rear section located on both sides of the catalytic pyrolysis reactor 9. These sections are used to adjust the heat exchange capacity coupled to the catalytic pyrolysis reactor 9, thereby controlling its temperature. Specifically, by adjusting the heat exchange capacity of the front section of the catalytic pyrolysis reactor 9, the temperature of the reactor can be controlled according to the optimal catalytic pyrolysis conditions for ammonia. The rear section of the heat exchanger pipe 10 is also used for counter-current heat exchange with the flue gas. The ammonia combustion status is monitored through flame observation, thermocouple 7 measurement of the combustion chamber temperature, and flue gas analysis of the flue gas composition. Adjustments to the fuel power, equivalence ratio, and temperature of the catalytic pyrolysis reactor 9 allow for low-emission combustion at higher ammonia power while ensuring good combustion conditions, thus improving the economic and environmental benefits of the plant.

[0040] The present invention provides a porous media combustion device for the catalytic pyrolysis combustion of ammonia. Ammonia is preheated in the catalytic pyrolysis reactor and partially pyrolyzed into nitrogen and hydrogen by an isomeric ruthenium-free catalyst. The pyrolyzed mixed gas (NH3, N2, and H2) is fully premixed with air in a premixing zone and then introduced into a porous media burner (PMB). The porous media burner is assembled from two porous ceramic blocks, with the upstream part made of yttrium-stabilized zirconia (YZA) and the downstream part made of silicon carbide (SiC). After the premixed gas enters the burner, it is combusted in an inert open cavity. By stabilizing the flame at the interface between the two thermally conductive ceramic structures, internal heat recirculation can be achieved to preheat the reactants. The catalytic pyrolysis reactor is coupled to a heat exchange chamber, and the combustion flue gas is used to preheat the ammonia in the catalytic pyrolysis reactor.

[0041] Ammonia is preheated in the catalytic pyrolysis reactor and decomposed into N2 and H2 by the catalyst. The H2 produced by pyrolysis co-combusts with NH3, which increases the flame propagation speed of the mixed gas and improves combustion stability. The ceramic structure upstream of the porous media burner has porous thermal conduction channels, which promotes heat transfer and prevents backfire. Internal heat recirculation occurs in the downstream solid porous matrix through thermal radiation and heat conduction, transferring some of the combustion heat to the porous media structure upstream of the burner, further preheating the reactants, increasing the flame propagation speed, increasing the combustion stability of the NH3 / H2 / air mixture, and improving the flammability limit. The high-temperature flue gas generated by combustion is heat-exchanged through a heat exchanger. On the one hand, it transfers energy externally, and on the other hand, through the coupling structure between the heat exchanger and the catalytic pyrolysis reactor, it preheats the ammonia to a temperature range of 300℃-500℃ for ammonia catalytic pyrolysis, requiring no external energy input and improving combustion efficiency.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A porous media combustion device for catalytic pyrolysis combustion of ammonia, characterized in that, It includes a gas delivery assembly, a premixing chamber (3), a porous media burner, an ignition device (6), a thermocouple (7), a heat exchange chamber (8), a catalytic pyrolysis reactor (9), a heat exchange water pipe (10), and a smoke hood (11). The gas delivery assembly includes an air inlet (1) and an ammonia inlet (2); the premixing chamber (3) includes a porous foam block; the porous media burner includes an upstream porous media burner (4) and a downstream porous media burner (5); an ignition device (6) is also provided between the upstream porous media burner (4) and the downstream porous media burner (5); the catalytic pyrolysis reactor (9) includes a heat exchange structure and a catalyst carrier. The inlet of the catalytic pyrolysis reactor (9) is connected to the ammonia inlet (2); the inlet of the premixing chamber (3) is connected to the outlet of the catalytic pyrolysis reactor (9) and the air inlet (1); the upper side of the premixing chamber (3) is connected to the porous media burner; the outlet of the porous media burner is connected to the heat exchange chamber (8); the heat exchange water pipe (10) is arranged around the heat exchange chamber (8) for heat exchange; The heat exchange chamber (8) is coupled to the catalytic pyrolysis reactor (9). When ammonia is preheated in the catalytic pyrolysis reactor (9), it is partially catalytically pyrolyzed into N2 and H2. After being fully premixed with air in the premixing chamber (3), it enters the porous medium burner for combustion. The combustion flue gas enters the heat exchange chamber (8) to transport energy to the outside, and at the same time, it is used to preheat the ammonia inside the catalytic pyrolysis reactor (9) coupled to the heat exchange chamber (8). Several thermocouples (7) are installed inside the porous media burner and at the catalytic pyrolysis reactor (9) to measure the temperature at different heights of the combustion chamber and the temperature of the catalytic pyrolysis reactor (9); a smoke hood (11) is also installed on the top of the heat exchange chamber (8). The smoke hood (11) is used to collect the flue gas generated by combustion and measure the flue gas composition through a flue gas analyzer to further investigate the combustion state of ammonia. The upstream (4) of the porous media burner is made of yttrium-stabilized zirconium oxide material, and the pore density of the upstream (4) of the porous media burner is 20 PPI, which is used as a backfire prevention device; the downstream (5) of the porous media burner is made of silicon carbide material, and the pore density of the downstream (5) of the porous media burner is 10 PPI, which is used as the combustion zone.

2. The porous media combustion device for ammonia catalytic pyrolysis combustion according to claim 1, characterized in that, The catalyst of the catalytic pyrolysis reactor (9) is an isomer ruthenium-free catalyst. The catalyst is composed of CoNi alloy nanoparticles dispersed on a support of mixed oxides magnesium, cesium and strontium, and modified with K additive, represented as K-CoNialloy-MgOCeO2-SrO; the catalyst support includes Al2O3 spherical particles with a particle size of 3 mm-5 mm.

3. The porous media combustion device for catalytic pyrolysis combustion of ammonia according to claim 1, characterized in that, Both the upstream (4) and downstream (5) of the porous media burner are ceramic foam blocks with a thickness of 50 mm and a diameter of 100 mm.

4. The porous media combustion device for catalytic pyrolysis combustion of ammonia according to claim 1, characterized in that, Thermocouples 1-5 (7) are inserted into the porous medium burner and are in direct contact with the ceramic substrate to measure the temperature at different heights in the combustion chamber; Thermocouple 6 (7) is placed at the coupling point between the catalytic pyrolysis reactor (9) and the heat exchange chamber (8) to measure the temperature of the catalytic pyrolysis reactor (9).

5. The porous media combustion device for ammonia catalytic pyrolysis combustion according to claim 4, characterized in that, The thermocouple (7) No. 6, which is arranged inside the porous medium burner, is inserted 10 mm into the interior of the porous medium burner.

6. The porous media combustion device for ammonia catalytic pyrolysis combustion according to claim 1, characterized in that, The premixed chamber (3) and the protective layer outside the porous medium burner are both made of quartz glass and are used to observe the combustion flame, detect the combustion status and combustion stability.

7. The porous media combustion device for catalytic pyrolysis combustion of ammonia according to claim 1, characterized in that, The porous medium burner and the heat exchange chamber (8) are both surrounded by heat insulation structures, which are used to reduce heat loss from the surrounding walls.

8. The porous media combustion device for catalytic pyrolysis combustion of ammonia according to claim 1, characterized in that, The hot water exchange pipe (10) includes a front section structure and a rear section structure located on both sides of the catalytic pyrolysis reactor (9). The front section structure and the rear section structure of the hot water exchange pipe (10) are used to adjust the heat exchange of the catalytic pyrolysis reactor (9) and thereby regulate the temperature of the catalytic pyrolysis reactor (9).

9. The porous media combustion device for ammonia catalytic pyrolysis combustion according to claim 8, characterized in that, The rear section of the hot water exchange pipe (10) is also used for countercurrent heat exchange with the flue gas.

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