Ammonia fuel porous medium combustor with wide load stable combustion and low nitrogen emission

Abstract

The present application relates to a kind of wide load stable combustion and low nitrogen emission ammonia fuel porous medium burner, belong to clean combustion and zero carbon fuel utilization technical field.It includes: ammonia fuel import pipe fitting, ammonia catalytic cracking component, porous medium combustion support component are sequentially arranged from inside to outside;Fuel enters ammonia catalytic cracking component by ammonia fuel import pipe fitting;Fuel in ammonia catalytic cracking component is set to crack, generate mixed gas, mixed gas enters between ammonia catalytic cracking component and porous medium combustion support component;Medium is arranged between ammonia catalytic cracking component and porous medium combustion support component, mixture formed by introduced air and mixed gas is rich combustion condition, and is discharged from the right side of porous medium combustion support component.The present application can efficiently organize ammonia catalytic cracking, porous medium reinforced combustion and catalytic denitration integrated burner, realize the efficient stable clean combustion of ammonia fuel.

Description

Technical Field

[0001] This invention relates to a porous media burner, belonging to the field of clean combustion and zero-carbon fuel utilization technology. Background Technology

[0002] Ammonia, as a zero-carbon fuel, has attracted widespread attention due to its advantages such as low storage and transportation costs and high energy density. However, traditional ammonia fuel burners face two major challenges: first, a narrow stable combustion range, as ammonia has a low burning rate and high ignition energy, making it prone to flameout at low loads and easy to blow off at high loads; second, difficulty in NOx emission control, as ammonia fuel itself contains nitrogen, which readily generates fuel-type NOx under high-temperature oxidizing atmospheres. The unique combustion characteristics of ammonia fuel limit its wide-load operation and pollutant emission reduction in industrial applications. Conventional enhanced combustion methods, such as blending with active fuels like hydrogen and natural gas, increase fuel complexity and cost.

[0003] Partial catalytic cracking of ammonia fuel can generate hydrogen in situ, improving combustion activity and serving as an effective method for enhancing combustion. Porous media combustion technology achieves heat recirculation and superenthalpic combustion in the combustion zone through the thermal conductivity and radiation of a solid matrix, increasing the combustion rate and flammability limit. Simultaneously, the temperature homogenization effect of the porous media suppresses localized high temperatures, which helps reduce nitrogen oxide (NOx) emissions. Furthermore, porous media can serve as catalyst supports, integrating enhanced combustion and catalytic functions.

[0004] However, traditional porous media burners offer limited improvement in the stable combustion of ammonia fuel, and their functional modules, such as pyrolysis, combustion, and denitrification, are loosely coupled, lacking coordinated control over the pyrolysis and combustion processes. Furthermore, the catalyst operates in harsh environments, is inconvenient to replace and maintain, and has a complex overall structure, making standardized and modular applications difficult.

[0005] The invention patent application "A self-heating ammonia fuel decomposition coupled catalytic combustion system and method" (application number 2011050038.X) designs a complex system-level solution that includes molten salt heat exchange and steam utilization. It utilizes molten salt circulation and a concentric cylindrical structure to achieve thermal coupling between pyrolysis and combustion. The system is complete and recovers waste heat effectively, but the overall structure is large and has many subsystems. It belongs to the level of power plant boilers or industrial furnace systems, rather than modular burner units that can be flexibly arranged.

[0006] The invention patent "An ammonia burner based on plasma pyrolysis, thermal pyrolysis, and plasma-assisted combustion and its operation method" (patent number 2010260532.8) directly burns the porous medium of the catalyst layer, making the catalyst prone to deactivation. The catalyst is in direct contact with the combustion flame, making it susceptible to deactivation due to high-temperature sintering. The overall structure is loose, with the pyrolysis, combustion, and combustion modules arranged independently, resulting in significant heat loss. Furthermore, the air stage ratio and pyrolysis rate are difficult to control and monitor, leading to poor adaptability to operating conditions.

[0007] The invention patent "An ammonia burner and its operation method based on thermocatalytic cracking, multi-stage zoned combustion and plasma-assisted combustion" (patent number 2011114741.2) faces challenges related to plasma lifespan and cost, making it difficult to control the stage ratio. Plasma equipment is expensive and has a short lifespan; fluctuations in discharge power can easily lead to combustion instability. The multi-stage flame correlation logic is complex, and a single module failure can trigger overall combustion collapse. Furthermore, the lack of a specific backfire prevention design makes high-hydrogen-content mixtures prone to reverse combustion safety hazards.

[0008] The invention patent "A Combustion Chamber for Ammonia-Hydrogen Co-combustion and a Combustion Method for Ammonia-Hydrogen Co-combustion" (patent number 2011257600.1) relies solely on catalytic cracking to improve ammonia flame stability. Catalyst deactivation or fluctuations in operating conditions can easily induce flame instability, making it difficult to maintain stable operation. The limited contact area between the catalyst box and ammonia results in insufficient hydrogen production and poor flame stability. The lack of a denitrification design leads to high NOx emissions. Furthermore, the combustion chamber and hydrogen production chamber are welded together, requiring disassembly and cutting for catalyst replacement, resulting in high maintenance costs.

[0009] The invention patent "A Gas Turbine Staged Combustion Device Coupled with Ammonia Fuel Pre-pyrolysis" (patent number 20103481.5) suffers from problems with the inability to control and monitor the stage ratio and pyrolysis rate, relies on fixed structural parameters, and has poor adaptability to operating conditions. It relies solely on the reduction of NO by a reducing atmosphere. x The denitrification efficiency is limited and easily affected by combustion fluctuations. The catalyst is fixedly packed in an annular channel, and maintenance and replacement require disassembly of the entire structure, making the operation complex. There is no secondary treatment process for unburned ammonia, resulting in low ammonia burnout rate and a risk of ammonia escape.

[0010] Therefore, there is an urgent need to develop a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions to solve the above-mentioned technical problems. Summary of the Invention

[0011] To address the aforementioned problems, a porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions is provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0012] The technical solution of the present invention:

[0013] A porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions includes: an ammonia fuel inlet pipe, an ammonia catalytic cracking component, and a porous media combustion support component arranged sequentially from the inside to the outside; Fuel enters the ammonia catalytic cracking unit through the ammonia fuel inlet pipe; The fuel in the medium installed in the ammonia catalytic cracking component is cracked to generate a mixed gas, which enters between the ammonia catalytic cracking component and the porous medium combustion support component. A medium is provided between the ammonia catalytic cracking component and the porous media combustion support component. The mixture formed by the introduced air and the mixed gas is under fuel-rich conditions and is discharged from the right side of the porous media combustion support component.

[0014] Preferably, the porous media combustion support assembly has ammonia catalytic cracking assembly assembly holes and combustion flue gas outlets at both ends. The chamber sidewall of the porous media combustion support assembly has a primary air channel and a secondary air channel arranged sequentially from the inside to the outside. The left side of the porous media combustion support assembly is the porous media combustion chamber, and the right side of the porous media combustion support assembly is the catalytic denitrification chamber. The primary air outlet of the primary air channel is corresponding to the porous media combustion chamber, and the secondary air outlet of the secondary air channel is corresponding to the catalytic denitrification chamber.

[0015] Preferably, the primary air channel is S-shaped, the primary air inlet of the primary air channel is located on the left side of the porous medium combustion support assembly, the primary air outlet of the primary air channel is correspondingly set to the left end of the porous medium combustion chamber, and the secondary air inlet of the secondary air channel is located on the left side of the porous medium combustion support assembly.

[0016] Preferably, the ammonia catalytic cracking assembly has an ammonia catalytic cracking chamber, the inner cavity of the right outer wall of the ammonia catalytic cracking assembly is provided with heat exchange fins, the left side of the ammonia catalytic cracking chamber has an ammonia catalytic cracking assembly inlet, the right end of the ammonia catalytic cracking chamber is connected to the inner cavity, and the inner cavity is connected to the porous media combustion chamber through the ammonia cracking gas outlet.

[0017] Preferably, the ammonia catalytic cracking assembly has an ammonia catalytic cracking assembly flange, the left end of the porous media combustion support assembly has a porous media combustion support assembly flange, the center of the porous media combustion support assembly flange is provided with an ammonia catalytic cracking assembly assembly hole, the right side of the ammonia catalytic cracking assembly passes through the ammonia catalytic cracking assembly assembly hole and is disposed in the porous media combustion chamber, and the ammonia catalytic cracking assembly flange is connected to the porous media combustion support assembly flange.

[0018] Preferably, the outer wall of the secondary air flow channel is provided with a catalytic denitrification temperature measurement channel, and the left outer wall of the ammonia catalytic cracking component is provided with an ammonia catalytic cracking component temperature measurement channel.

[0019] Preferably, the left end of the ammonia fuel inlet pipe is the ammonia fuel inlet pipe inlet, and the right end of the ammonia fuel inlet pipe is provided with a porous channel for the ammonia fuel inlet pipe. The ammonia fuel inlet pipe is located in the ammonia catalytic cracking chamber through the inlet of the ammonia catalytic cracking component.

[0020] Preferably, the side wall of the ammonia fuel inlet pipe fitting is provided with an ammonia fuel inlet pipe fitting temperature measuring hole and an ammonia fuel inlet pipe fitting external thread. The ammonia fuel inlet pipe fitting temperature measuring hole is correspondingly set with the ammonia catalytic cracking component temperature measuring channel. The inner wall of the ammonia catalytic cracking chamber is provided with an ammonia catalytic cracking component internal thread. The ammonia fuel inlet pipe fitting external thread is connected with the ammonia catalytic cracking component internal thread. The ammonia catalytic cracking component temperature measuring channel and the catalytic denitrification temperature measuring channel are used for inserting thermocouples for temperature measurement.

[0021] Preferably, a porous medium for ammonia catalytic cracking is provided on the right side of the ammonia catalytic cracking chamber. Between the porous medium combustion support assembly and the ammonia catalytic cracking assembly, a metal screen layer, a backfire prevention porous medium, a combustion porous medium, an ammonia catalytic cracking porous medium, and a catalytic denitrification porous medium are arranged sequentially from left to right. A catalytic denitrification porous medium is provided in the catalytic denitrification chamber. The metal screen layer is correspondingly arranged with the primary air outlet and the ammonia cracking gas outlet.

[0022] Preferably, the metal screen layer is made of ammonia-resistant metal material, the tempering-proof layer porous medium is made of low thermal conductivity small-pore ceramic material, the combustion layer porous medium is made of high thermal conductivity large-pore ceramic material, the ammonia catalytic cracking layer porous medium uses a transition metal catalyst for ammonia cracking catalyst, and the catalytic denitrification layer porous medium uses a large-pore ceramic material.

[0023] The present invention has the following beneficial effects: This invention utilizes combustion heat to drive ammonia catalytic cracking, eliminating the need for an external heat source and improving the overall thermal efficiency of the system. The hydrogen produced by cracking improves the combustion activity of ammonia in situ, and combined with the advantages of porous media-assisted thermal recirculation to enhance combustion, it significantly broadens the stable combustion limit and load adjustment range. The porous media combustion layer, combined with a metal screen and a flashback prevention layer, effectively prevents flashback and improves combustion safety. The porous media of the combustion layer is loaded with an infrared radiation coating to enhance radiative heat transfer and improve thermal efficiency. By adopting a combination of air staging and catalytic denitrification, NOx emissions are significantly lower than those of conventional combustion methods. The modular structure allows for flexible assembly and is suitable for single or array arrangements, making it widely applicable to various ammonia combustion scenarios. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions.

[0025] Figure 2 This is a schematic diagram of the porous media combustion support assembly.

[0026] Figure 3 This is a schematic diagram of the structure of an ammonia catalytic cracking unit.

[0027] Figure 4 This is a schematic diagram of the ammonia fuel inlet pipe fittings.

[0028] Figure 5 for Figure 1 Cross-sectional schematic diagram of the medium and seal. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0030] Specific implementation method one: Combining Figure 1-5 This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions, comprising: an ammonia fuel inlet pipe, an ammonia catalytic cracking component, and a porous media combustion support component arranged coaxially from the inside to the outside; a medium is disposed inside the ammonia catalytic cracking component; and a medium is disposed between the ammonia catalytic cracking component and the porous media combustion support component. The ammonia combustion catalytic porous media burner proposed in this invention integrates catalytic cracking, porous media combustion, and catalytic denitrification functions. It utilizes combustion heat to drive ammonia catalytic cracking, eliminating the need for an external heat source and improving the overall thermal efficiency of the system. The hydrogen generated from cracking improves ammonia combustion activity in situ, and combined with the advantages of porous media-assisted heat recirculation to enhance combustion, it significantly broadens the stable combustion limit and load adjustment range. The porous media combustion layer, combined with a metal mesh and a flashback prevention layer, effectively prevents flashback and improves combustion safety. The porous media of the combustion layer is loaded with an infrared radiation coating, enhancing radiative heat transfer and improving thermal efficiency. By employing a combination of air staging and catalytic denitrification, NOx emissions are significantly lower than conventional combustion methods. Its modular structure allows for flexible assembly and is suitable for single or array arrangements, making it widely applicable to various ammonia combustion scenarios. This invention is an integrated burner that can efficiently organize ammonia catalytic cracking, porous media enhanced combustion and catalytic denitrification, thereby achieving efficient, stable and clean combustion of ammonia fuel.

[0031] Specific Implementation Method Two: Combining Figure 1-5This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. The porous media combustion support assembly has ammonia catalytic cracking component assembly holes 12 and combustion flue gas outlets 21 at both ends of its chamber. The sidewalls of the porous media combustion support assembly chamber have primary air channels and secondary air channels arranged sequentially from the inside to the outside. The left side of the porous media combustion support assembly chamber is a porous media combustion chamber 17, and the right side is a catalytic denitrification chamber 18. The primary air outlet 14 of the primary air channel connects to the secondary air outlet. The porous media combustion chamber 17 is correspondingly configured, and the secondary air outlet 20 of the secondary air flow channel is correspondingly configured with the catalytic denitrification chamber 18. The primary air and secondary air flow channels are enclosed in an annular chamber outside the porous media combustion chamber 17 to preheat the air to increase the air temperature, enhance the stability of ammonia combustion, and at the same time protect the metal wall in the porous media combustion chamber 17 from overheating and prevent the metal wall from burning and cracking. The combustion reaction module shell is provided with a primary air inlet 15, and the primary air inlet 15, the cracked gas outlet and the inlet of the porous media combustion chamber 17 are in fluid communication.

[0032] Specific implementation method three: Combining Figure 1-5 This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. The primary air flow channel has an S-shaped cross-section, creating a stepped structure on the inner wall of the porous media combustion support assembly. The radial steps of this stepped structure divide the cavity of the porous media combustion support assembly into a porous media combustion chamber 17 and a catalytic denitrification chamber 18. The primary air inlet 15 of the primary air flow channel is located on the left side outside the porous media combustion support assembly cavity, and the primary air outlet 14 of the primary air flow channel is correspondingly located at the left end of the porous media combustion chamber 17. The secondary air inlet 16 of the secondary air flow channel is also located on the left side outside the porous media combustion support assembly cavity. The porous media combustion chamber 17 is located along the airflow direction... A metal mesh layer 24, a backfire-proof porous medium layer 25, and a combustion porous medium layer 26 are sequentially arranged. The catalytic denitrification chamber 18 is filled with the catalytic denitrification porous medium layer 28. Primary air enters the front section of the combustion chamber through the primary air inlet 15, mixes with the cracked gas from the ammonia catalytic cracking chamber 10, and then burns in the combustion porous medium layer 26. Secondary air is sent into the catalytic denitrification chamber 18 through the secondary air inlet 16, mixes with the combustion flue gas, and undergoes a selective catalytic reduction reaction on the catalytic denitrification porous medium layer 28 to further reduce NOx emissions. By flexibly adjusting the primary and secondary air injection ratio, a staged combustion mode of fuel-rich and fuel-lean combustion is formed in the porous medium, which synergistically controls the combustion stability of ammonia / air and NOx emissions.

[0033] Specific implementation method four: Combination Figure 1-5This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. The ammonia catalytic cracking assembly has an ammonia catalytic cracking chamber 10. Heat exchange fins 11 are provided in the inner cavity of the right outer wall of the ammonia catalytic cracking assembly. An ammonia catalytic cracking assembly inlet 5 is located on the left side of the chamber 10. The right end of the chamber 10 communicates with the inner cavity, which is connected to a porous media combustion chamber 17 via an ammonia cracked gas outlet 9. The heat exchange fins 11 are located between the right end outlet of the ammonia catalytic cracking chamber 10 and the ammonia cracked gas outlet 9. An ammonia fuel inlet pipe passes through the ammonia catalytic cracking assembly and is threadedly connected to it. It has porous channels inside for the transport and distribution of ammonia fuel. Multiple sets of heat exchange fins 11 are provided on the outer wall of the ammonia catalytic cracking chamber 10 to enhance heat transfer between the chamber and the combustion chamber, promoting the cracking reaction.

[0034] Specific Implementation Method Five: Combining Figure 1-5 This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. The ammonia catalytic cracking assembly includes an ammonia catalytic cracking assembly flange 8, dividing the outer wall of the ammonia catalytic cracking assembly into a left outer wall and a right outer wall. A porous media combustion support assembly flange 13 is located at the left end of the flange 13, with an ammonia catalytic cracking assembly assembly hole 12 at its center. The right side of the ammonia catalytic cracking assembly passes through the assembly hole 12 and is positioned within the porous media combustion chamber 17. The outer surface of the right end of the ammonia catalytic cracking assembly is coplanar with the radial step surface of the stepped structure. The ammonia cracked gas outlet 9 is located on the left side of the porous media combustion chamber 17. The ammonia catalytic cracking assembly flange 8 and the porous media combustion support assembly flange 13 are connected by bolt assemblies 22, and a sealing gasket 23 is provided between them. All components are connected via flanges, bolt assemblies 22, and sealing gaskets 23, forming a modular and detachable structure for easy maintenance and catalyst replacement.

[0035] Specific Implementation Method Six: Combination Figure 1-5 This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. A catalytic denitrification temperature measurement channel 19 is provided on the outer wall of the secondary air flow channel corresponding to the secondary air outlet 20. An ammonia catalytic cracking component temperature measurement channel 6 is provided on the left outer wall of the ammonia catalytic cracking component.

[0036] Specific implementation method seven: Combination Figure 1-5 This embodiment describes a porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions. The left end of the ammonia fuel inlet pipe is the ammonia fuel inlet pipe inlet 1, and the right end of the ammonia fuel inlet pipe is provided with an ammonia fuel inlet pipe porous channel 4. The ammonia fuel inlet pipe is located in the ammonia catalytic cracking chamber 10 through the ammonia catalytic cracking component inlet 5.

[0037] Specific implementation method eight: Combination Figure 1-5 This embodiment describes a porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions. The side wall of the ammonia fuel inlet pipe has an ammonia fuel inlet pipe temperature measuring hole 2 and an ammonia fuel inlet pipe external thread 3, arranged from left to right. The ammonia fuel inlet pipe temperature measuring hole 2 corresponds to the ammonia catalytic cracking component temperature measuring channel 6. The inner wall of the ammonia catalytic cracking chamber 10 has an ammonia catalytic cracking component internal thread 7. The ammonia fuel inlet pipe external thread 3 and the ammonia catalytic cracking component internal thread 7 are screwed together. The ammonia catalytic cracking component temperature measuring channel 6 and the catalytic denitrification temperature measuring channel 19 are used to insert thermocouples for temperature measurement. The ammonia catalytic cracking component temperature measuring channel 6 and the catalytic denitrification temperature measuring channel 19 are respectively used to monitor the ammonia catalytic cracking temperature and the catalytic denitrification temperature to prevent catalyst deactivation.

[0038] Specific Implementation Method Nine: Combining Figure 1-5 This embodiment describes a porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions. An ammonia catalytic cracking layer porous media 27 is disposed on the right side of the ammonia catalytic cracking chamber 10. The ammonia catalytic cracking layer porous media 27 is located on the right side of the porous channel 4 of the ammonia fuel inlet pipe. Within the porous media combustion chamber 17 between the porous media combustion support assembly and the ammonia catalytic cracking assembly, from left to right, a metal screen layer 24, a backfire prevention layer porous media 25, a combustion layer porous media 26, an ammonia catalytic cracking layer porous media 27, and a catalytic denitrification layer porous media 28 are sequentially arranged. The catalytic denitrification chamber 18... The device is equipped with a porous medium 28 for catalytic denitrification, and a metal screen layer 24 is correspondingly arranged with the primary air outlet 14 and the ammonia cracking gas outlet 9. The ammonia catalytic cracking component is equipped with an ammonia catalytic cracking chamber 10, which is filled with a porous medium 27 for ammonia catalytic cracking to achieve partial cracking of ammonia. Preferably, the ammonia cracking catalyst is a transition metal catalyst such as nickel-based or iron-based catalyst to reduce the cost of ammonia catalytic cracking. The hydrogen generated by cracking enters the porous medium layer as "ignition fuel". The extremely wide flammability limit and high burning rate of hydrogen significantly widen the low load lower limit of the burner to prevent flameout and the high load upper limit to prevent blow-off and target miss.

[0039] Specific Implementation Method Ten: Combining Figure 1-5This embodiment describes a porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions. The metal screen layer 24 is made of ammonia-corrosion-resistant metal material with an average pore size of less than 0.1 mm and a thickness of not less than 10 mm, used to prevent flashback under high pyrolysis rate conditions. The flashback-prevention porous medium 25 is a low-thermal-conductivity small-pore ceramic material used to drive the flame position within the combustion layer porous medium 26, with a PPI of 30-50, porosity of 55-90%, and thermal conductivity less than 30 W / (m·K), further preventing flashback. The combustion layer porous medium 26 is a high-thermal-conductivity large-pore ceramic material, with a high-infrared emissivity coating on its pore surface, promoting combustion heat recirculation and combustion zone temperature uniformity, improving flame temperature and flame stability in the combustion zone. A coating of one or more transition metal oxides such as manganese oxide, iron oxide, copper oxide, and cobalt oxide is used, with a PPI of 3-20, porosity of 55-90%, and thermal conductivity greater than 50. The ammonia cracking catalyst in the porous medium 27 of the ammonia catalytic cracking layer is a transition metal catalyst such as nickel-based or iron-based, which reduces the cost of ammonia catalytic cracking. The porous medium 28 of the catalytic denitrification layer uses macroporous ceramic materials to promote the full reaction of staged air entering the porous medium with unburned ammonia fuel. Preferably, the catalyst type is a copper-based catalytic coating with good high-temperature resistance, a PPI of 3~20, and a porosity of 55~90%.

[0040] Example 1: Combination Figure 1-5 The diagram shows a combustion device for ammonia fuel. In particular, it is a modular burner that highly integrates ammonia catalytic cracking, porous media combustion, air staging, and catalytic reduction denitrification technologies, suitable for industries such as civil, metallurgical, power generation, chemical, and transportation that require efficient, stable, and clean combustion of ammonia fuel.

[0041] The core components of the ammonia combustion catalytic porous media burner are ammonia fuel inlet pipe, ammonia catalytic cracking component, porous media combustion support component, metal screen layer 24, anti-backfire porous media layer 25, combustion porous media layer 26, ammonia catalytic cracking porous media layer 27, and catalytic denitrification porous media layer 28.

[0042] Ammonia fuel inlet pipe fittings ( Figure 4 ) is inserted into the ammonia catalytic cracking component assembly hole 12, and connected to the ammonia catalytic cracking component ( ) via the external thread 2. Figure 3 The internal thread 7 of the ammonia catalytic cracking assembly is used for assembly to support the porous medium 27 of the ammonia catalytic cracking layer in the ammonia catalytic cracking chamber 10. The centerlines of the ammonia catalytic cracking assembly temperature measuring hole 2 and the ammonia fuel inlet pipe temperature measuring channel 6 are aligned for inserting thermocouples for temperature measurement.

[0043] Ammonia catalytic cracking unit ( Figure 3After the metal mesh layer 24, the tempering-resistant porous medium layer 25, and the combustion-resistant porous medium layer 26 are connected, they are connected to the porous medium combustion support assembly through flange holes 8 and 13, bolt assembly 22, and sealing gasket 23. Figure 2 Assembly is performed. Preferably, the sealing gasket is a graphite gasket, a metal gasket, or a metal-graphite spiral wound gasket. After assembly, a porous media combustion chamber 17 is formed, which is used to fill the metal screen layer 24, the anti-backfire porous media layer 25, and the combustion layer porous media 26. The catalytic denitrification chamber 18 is used to fill the catalytic denitrification layer porous media 28, which is fixed by a slotted structure.

[0044] The device employs the following method: Ammonia fuel enters from the inlet 5 of the ammonia catalytic cracking assembly, passes through the porous channel 4 to reach the ammonia catalytic cracking chamber 10, and is cracked by the porous medium 24 of the ammonia catalytic cracking layer to generate a mixed gas containing nitrogen, hydrogen, and ammonia. The ammonia catalytic cracking chamber 10 is equipped with multiple sets of heat exchange fins 10, which are connected to the metal walls near both sides to enhance heat transfer between the ammonia catalytic cracking chamber 10 and the porous medium combustion chamber 17, promoting the provision of heat from the porous medium combustion chamber 17 to the ammonia catalytic cracking. Multiple sets of holes are opened on the heat exchange fins 11, allowing the cracked ammonia gas to reach the ammonia cracked gas outlet 9 through the heat exchange fins 12. Preferably, the cracking catalyst is a transition metal catalyst such as nickel-based or iron-based, and a thermocouple passes through the temperature measuring hole 2 and the temperature measuring channel 6 to monitor the ammonia catalytic cracking temperature. Preferably, a type K thermocouple is used, the catalytic cracking temperature is controlled between 400 and 900 °C, the porosity of the catalyst packing section is above 60%, ensuring that the ammonia cracking rate reaches above 20%, significantly improving flame stability and reducing NOx emissions. After cracking, the ammonia gas enters the porous medium combustion chamber 17 through the ammonia cracking gas outlet 9.

[0045] Air enters the porous media combustion chamber 17 through primary air inlet 15 and secondary air inlet 16. The flow channels between primary air inlet 15 and primary air outlet 14, and between secondary air inlet 16 and secondary air outlet 16, are enclosed in annular chambers around the porous media combustion chamber 17. This preheating process raises the air temperature to above 200°C, thereby enhancing ammonia combustion stability and protecting the metal walls of the porous media combustion chamber 17 from erosion and cracking at temperatures exceeding 600°C. Primary air exits from primary air outlet 14, mixes with the cracked ammonia gas, and then enters the porous media combustion chamber 17. Preferably, the mixture formed by primary air and cracked ammonia gas is under fuel-rich conditions. The metal mesh layer 24, the backfire prevention porous media layer 25, and the combustion layer porous media 26 in the porous media combustion chamber 17 have annular structures. The porous media ammonia cracking mixture and the oxidant mixture first enter the metal mesh layer 24, which effectively prevents backfire through quenching and high thermal conductivity heat dissipation. The metal mesh layer 24 is made of ammonia-resistant metal material with an average pore diameter of less than 0.5 mm and a thickness of not less than 10 mm. Then, the ammonia cracking mixture and oxidant mixture enter the tempering-resistant porous medium 25, which is made of small-pore ceramic material. This structure provides secondary tempering protection. The tempering-resistant porous medium 25 has a PPI of 30-50, a porosity of 55-90%, and a thermal conductivity of less than 30 W / (m·K). Preferably, the tempering-resistant porous medium 25 uses alumina and zirconium oxide materials. The ammonia cracking mixture and oxidant mixture are combusted in the combustion layer porous medium 26. The combustion layer porous medium 26 uses a macroporous ceramic material with a PPI of 3-20, a porosity of 55-90%, and a thermal conductivity greater than 50 W / (m·K). Preferably, the combustion layer porous medium 26 uses silicon carbide material. The combustion layer porous medium 26 employs an infrared radiation coating to reduce combustion heat loss and improve thermal efficiency. The infrared radiation coating is one or more transition metal oxides, applied by dip deposition or spraying, with a coating thickness of 5-100 μm. Preferably, a coating is a mixture of one or more manganese oxide, iron oxide, copper oxide, and cobalt oxide.

[0046] Secondary air enters through secondary air inlet 16 and exits through secondary air outlet into catalytic denitrification chamber 18. The secondary air entering catalytic denitrification chamber 18 is supported by airflow channels and ammonia cracking flow channels around its perimeter and center. Preferably, the secondary air inlets 16 are arranged symmetrically in a ring around catalytic denitrification chamber 18, with each inlet 16 employing multi-channel axial injection at its radial injection position, perpendicular to the flow direction of the combustion flue gas, to improve the uniformity of secondary air mixing. The secondary air entering catalytic denitrification chamber 18 reacts fully with unburned ammonia in the combustion flue gas. A porous catalytic denitrification layer 28 is provided within catalytic denitrification chamber 18. The porous catalytic denitrification layer 28 is made of macroporous ceramic material to promote mixing of secondary air and flue gas. Preferably, the PPI is 3-20, and the porosity is 55-90%. The porous catalytic denitrification layer 28 is used for the catalytic ammonia reduction of NOx process, and the catalyst is loaded using impregnation deposition or spraying methods, with a coating thickness of 0.001-10 μm. Preferably, the catalyst type uses a copper-based catalytic coating with good high-temperature resistance. A thermocouple passes through the catalytic denitrification temperature measurement channel 19 to monitor the ammonia combustion catalytic denitrification temperature, preventing excessive temperature from causing catalyst deactivation. Preferably, the thermocouple is an S-type or B-type thermocouple.

[0047] To further improve ammonia combustion efficiency, ammonia combustion parameters can be adjusted based on monitoring the ammonia catalytic cracking and catalytic denitrification temperatures.

[0048] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A porous media burner for ammonia fuel with wide-load stable combustion and low nitrogen emissions, characterized in that: include: The ammonia fuel inlet pipe, ammonia catalytic cracking assembly, and porous media combustion support assembly are arranged sequentially from the inside to the outside. Fuel enters the ammonia catalytic cracking unit through the ammonia fuel inlet pipe; The fuel in the medium installed in the ammonia catalytic cracking component is cracked to generate a mixed gas, which enters between the ammonia catalytic cracking component and the porous medium combustion support component. A medium, a mixture of air and mixed gas, is provided between the ammonia catalytic cracking component and the porous media combustion support component.

2. The ammonia fuel porous media burner with wide-load stable combustion and low nitrogen emissions according to claim 1, characterized in that: The porous media combustion support assembly is provided with an ammonia catalytic cracking assembly assembly hole (12) and a combustion flue gas outlet (21) at both ends. The chamber sidewall of the porous media combustion support assembly is provided with a primary air channel and a secondary air channel from the inside to the outside. The left side of the porous media combustion support assembly is a porous media combustion chamber (17), and the right side of the porous media combustion support assembly is a catalytic denitrification chamber (18). The primary air outlet (14) of the primary air channel is correspondingly set to the porous media combustion chamber (17), and the secondary air outlet (20) of the secondary air channel is correspondingly set to the catalytic denitrification chamber (18).

3. The ammonia fuel porous media burner with wide-load stable combustion and low nitrogen emissions according to claim 2, characterized in that: The primary air channel is S-shaped. The primary air inlet (15) of the primary air channel is located on the left side of the porous medium combustion support assembly. The primary air outlet (14) of the primary air channel is correspondingly set at the left end of the porous medium combustion chamber (17). The secondary air inlet (16) of the secondary air channel is located on the left side of the porous medium combustion support assembly.

4. A porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions according to claim 2 or 3, characterized in that: The ammonia catalytic cracking assembly has an ammonia catalytic cracking chamber (10). The inner cavity of the right outer wall of the ammonia catalytic cracking assembly is provided with heat exchange fins (11). The left side of the ammonia catalytic cracking chamber (10) has an ammonia catalytic cracking assembly inlet (5). The right end of the ammonia catalytic cracking chamber (10) is connected to the inner cavity. The inner cavity is connected to the porous medium combustion chamber (17) through the ammonia cracking gas outlet (9).

5. The ammonia fuel porous media burner with wide-load stable combustion and low nitrogen emissions according to claim 4, characterized in that: The ammonia catalytic cracking assembly has an ammonia catalytic cracking assembly flange (8), and the left end of the porous media combustion support assembly has a porous media combustion support assembly flange (13). The center of the porous media combustion support assembly flange (13) is provided with an ammonia catalytic cracking assembly assembly hole (12). The right side of the ammonia catalytic cracking assembly passes through the ammonia catalytic cracking assembly assembly hole (12) and is located in the porous media combustion chamber (17). The ammonia catalytic cracking assembly flange (8) is connected to the porous media combustion support assembly flange (13).

6. The ammonia fuel porous media burner with wide-load stable combustion and low nitrogen emissions according to claim 4, characterized in that: The outer wall of the secondary air flow channel is provided with a catalytic denitrification temperature measurement channel (19), and the left outer wall of the ammonia catalytic cracking component is provided with an ammonia catalytic cracking component temperature measurement channel (6).

7. A porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions according to claim 6, characterized in that: The left end of the ammonia fuel inlet pipe is the ammonia fuel inlet pipe inlet (1), and the right end of the ammonia fuel inlet pipe is provided with a porous channel (4). The ammonia fuel inlet pipe is set in the ammonia catalytic cracking chamber (10) through the ammonia catalytic cracking component inlet (5).

8. A porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions according to claim 7, characterized in that: The side wall of the ammonia fuel inlet pipe is provided with an ammonia fuel inlet pipe temperature measuring hole (2) and an ammonia fuel inlet pipe external thread (3). The ammonia fuel inlet pipe temperature measuring hole (2) is correspondingly provided with the ammonia catalytic cracking component temperature measuring channel (6). The inner wall of the ammonia catalytic cracking chamber (10) is provided with an ammonia catalytic cracking component internal thread (7). The ammonia fuel inlet pipe external thread (3) is connected to the ammonia catalytic cracking component internal thread (7). The ammonia catalytic cracking component temperature measuring channel (6) and the catalytic denitrification temperature measuring channel (19) are used to insert thermocouples for temperature measurement.

9. A porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions according to claim 8, characterized in that: A porous medium (27) for ammonia catalytic cracking is provided on the right side of the ammonia catalytic cracking chamber (10). A porous medium for ammonia catalytic cracking is provided between the porous medium combustion support assembly and the ammonia catalytic cracking assembly from left to right. A porous medium for ammonia catalytic cracking is provided in the following order: a metal screen layer (24), a porous medium for backfire prevention layer (25), a porous medium for a combustion layer (26), a porous medium for ammonia catalytic cracking layer (27), and a porous medium for catalytic denitrification layer (28). A porous medium for catalytic denitrification layer (28) is provided in the catalytic denitrification chamber (18). The metal screen layer (24) is provided in the corresponding position to the primary air outlet (14) and the ammonia cracking gas outlet (9).

10. A porous ammonia fuel burner with wide-load stable combustion and low nitrogen emissions according to claim 9, characterized in that: The metal screen layer (24) is made of ammonia-resistant metal material, the tempering layer porous medium (25) is a small-pore ceramic material with low thermal conductivity, the combustion layer porous medium (26) is a large-pore ceramic material with high thermal conductivity, the ammonia catalytic cracking layer porous medium (27) is a transition metal catalyst, and the catalytic denitrification layer porous medium (28) is made of large-pore ceramic material.

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