Ammonia fuel regenerative combustion device
By integrating ammonia pyrolysis and denitrification functions into an ammonia fuel regenerative combustion device, the problems of unstable ammonia fuel flame and nitrogen oxide emissions have been solved, achieving efficient zero-carbon combustion and low emissions, and optimizing the system design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING CISDI THERMAL & ENVIRONMENTAL ENG CO LTD
- Filing Date
- 2025-04-23
- Publication Date
- 2026-05-26
AI Technical Summary
Existing technologies using ammonia as fuel suffer from flame instability and nitrogen oxide emissions, and the systems are complex, energy-intensive, and inefficient, making large-scale application difficult.
A regenerative combustion device for ammonia fuel is designed, integrating ammonia cracking and denitrification functions. By loading a catalyst onto the regenerator and optimizing the porosity design, efficient ammonia cracking and efficient flue gas denitrification are achieved, thereby reducing NOx emissions.
Improve flame stability, increase ammonia cracking efficiency and denitrification efficiency, reduce catalyst consumption, achieve zero carbon emissions from the heating furnace, and meet pollutant emission standards.
Smart Images
Figure CN224284611U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of energy conservation and emission reduction, and relates to an ammonia fuel regenerative combustion device. Background Technology
[0002] Regenerative thermal combustion technology holds a significant position in the industrial sector due to its unique advantages. It employs a regenerative burner, alternating between air or gaseous fuel and flue gas, allowing them to flow through a regenerator to achieve large-scale recovery of the sensible heat from the high-temperature flue gas. This characteristic has led to the widespread application of regenerative thermal combustion technology in numerous fields such as industrial furnaces and heating furnaces, making it a powerful tool for energy conservation and emission reduction in industrial production.
[0003] However, with the introduction of the "dual carbon" target, the application of traditional hydrocarbon fuels in regenerative combustion burners faces severe challenges. Finding a "zero-carbon fuel" to replace traditional fuels has become key to promoting the sustainable development of regenerative combustion technology.
[0004] Hydrogen and ammonia, as two of the few zero-carbon fuels with industrial applications, have attracted considerable attention. From the perspectives of cost and application experience, ammonia has significant advantages over hydrogen. Currently, the high costs of hydrogen production, transportation, and storage limit its large-scale application. In contrast, ammonia has relatively low production, transportation, and storage costs, and has accumulated rich application experience in other industrial sectors, making it a potential candidate for large-scale application in regenerative thermal radiators.
[0005] However, ammonia also presents several problems as a fuel. Firstly, ammonia has a low flame propagation speed and a narrow ignition range, leading to an unstable flame, which undoubtedly increases safety hazards during combustion. In industrial production, stable combustion is crucial for ensuring safe equipment operation and production efficiency, and this characteristic of ammonia significantly hinders its application. Secondly, ammonia contains nitrogen, making it a nitrogen-containing fuel, which produces large amounts of nitrogen oxides during combustion, contradicting strict government emission standards. If the nitrogen oxide emission problem cannot be effectively addressed, the application of ammonia as a fuel will be severely limited.
[0006] To address the combustion stability and nitrogen oxide emissions issues associated with ammonia as a fuel, researchers have proposed several solutions. To improve combustion stability, a common approach is to mix hydrogen and ammonia fuels before feeding them into the combustion unit, utilizing the flammability of hydrogen to compensate for the insufficient combustion of ammonia; alternatively, hydrogen and ammonia fuels can be fed into the combustion unit separately, allowing for flexible adjustment of fuel supply based on combustion demands; another method is to pre-crack ammonia fuel partially or completely into hydrogen before feeding it into the combustion unit, thereby improving fuel combustibility. To reduce nitrogen oxide emissions, SCR (Selective Catalytic Reduction) or SNCR (Selective Non-Catalytic Reduction) denitrification technologies are typically used to treat flue gas and ensure it meets emission standards.
[0007] However, existing technologies typically employ separate hydrogen storage, cracking, and denitrification units to achieve these functions. This design approach has numerous drawbacks: the system is complex, energy-intensive, and inefficient. The complex system increases equipment investment and operation and maintenance costs, the high energy consumption contradicts the goals of energy conservation and emission reduction, and the low efficiency affects the stability and economy of the entire combustion process.
[0008] Therefore, in the future, it is necessary to further explore more efficient and integrated solutions that integrate hydrogen storage, cracking, denitrification and other functions into one, optimize system design, reduce energy consumption and improve efficiency, so as to promote the large-scale application of ammonia as a "zero-carbon fuel" in regenerative combustion technology and contribute to the realization of the "dual carbon" goal. Utility Model Content
[0009] In view of this, the purpose of this utility model is to provide an ammonia fuel regenerative combustion device that can improve flame stability, increase ammonia cracking efficiency and denitrification efficiency, and reduce NO in the combustion device. x Emissions will be reduced to achieve zero carbon emissions from the heating furnace.
[0010] To achieve the above objectives, this utility model provides the following technical solution:
[0011] A regenerative combustion device for ammonia fuel includes an ammonia fuel regenerative chamber and a combustion-supporting chamber, both connected to a furnace. A three-way reversing valve is provided at the end of the ammonia fuel regenerative chamber away from the furnace for alternately introducing ammonia fuel and discharging flue gas. An ammonia pyrolysis regenerative body, a denitrification reducing agent injector, and a denitrification regenerative body are sequentially arranged within the ammonia fuel regenerative chamber along the direction from the furnace towards the three-way reversing valve. The porosity of both the ammonia pyrolysis and denitrification regenerative bodies gradually decreases along the direction of flue gas outflow (ammonia inflow). A combustion-supporting gas inlet is provided at the end of the combustion-supporting chamber away from the furnace.
[0012] Optionally, the furnace sidewall is provided with at least two communication ports, and the ammonia fuel heat storage box and the combustion-supporting box are respectively fastened to the communication ports, so that the ammonia fuel heat storage box and the combustion-supporting box are connected to the furnace through the communication ports.
[0013] Optionally, the denitrification reducing agent injector penetrates the shell of the ammonia fuel heat storage tank.
[0014] Optionally, the denitrification reducing agent injector is equipped with a flow control valve.
[0015] Optionally, the angle of the denitrification reducing agent injector on the housing is adjustable to facilitate adjustment of the injection angle of the denitrification reducing agent.
[0016] Optionally, the porosity of the heat storage body at the end where flue gas flows in is 70% to 75%, and the porosity of the heat storage body at the end where flue gas flows out is 60% to 65%. The porosity of the entire ammonia cracking heat storage body decreases from large to small along the direction of flue gas outflow (ammonia inflow).
[0017] Optionally, the ammonia cracking regenerator has an ammonia cracking catalyst loaded on its ceramic framework.
[0018] Optionally, the three-way reversing valve is connected to a flue gas pipe and an ammonia fuel inflow pipe, and valves are respectively installed on the flue gas pipe and the ammonia fuel inflow pipe.
[0019] Optionally, the porosity of the heat storage body at the end where flue gas flows in is 55% to 60%, and the porosity of the heat storage body at the end where flue gas flows out is 45% to 50%. The porosity of the entire heat storage body decreases from large to small along the direction of flue gas outflow (ammonia inflow).
[0020] Optionally, the ceramic framework of the denitrification regenerator is loaded with an SCR reduction catalyst.
[0021] The beneficial effects of this utility model are as follows:
[0022] This invention's device can improve flame stability, increase ammonia cracking efficiency and denitrification efficiency, and reduce NO in combustion devices. x The emissions are reduced, the consumption of catalytic substances is decreased, and the flue gas emissions do not contain CO2, achieving zero carbon emissions from the regenerative heating furnace while meeting the process requirements and pollutant emission indicators.
[0023] This device loads ammonia cracking catalyst and SCR reduction catalyst onto a ceramic framework of a heat storage medium, with the porosity of the heat storage medium designed to gradually change along the gas flow direction. Ammonia preheating process: The cracking reaction is completed in the ammonia cracking heat storage medium to produce a hydrogen-nitrogen mixed fuel, improving flame stability. Along the ammonia flow direction (ammonia temperature gradually increases), the porosity of the ammonia cracking heat storage medium gradually increases, improving the ammonia cracking catalytic efficiency and reducing ammonia cracking catalyst consumption while maintaining constant friction resistance. Flue gas heat storage process: The SCR reduction reaction of nitrogen oxides is completed in the denitrification heat storage medium to reduce NO. x Emissions: Along the flue gas flow direction (flue gas temperature gradually decreases), the porosity of the denitrification regenerator gradually decreases, improving the denitrification catalytic efficiency and reducing the consumption of denitrification catalyst while maintaining constant friction resistance. Furthermore, the flue gas contains no CO2, achieving zero carbon emissions from the regenerative heating furnace while meeting the heating process requirements and pollutant emission standards.
[0024] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description
[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:
[0026] Figure 1 This is a schematic diagram of the device of this utility model.
[0027] Figure label:
[0028] Ammonia fuel heat storage box 1, shell 11, fuel side box furnace connection port 12, ammonia cracking heat storage body 13, denitrification reducing agent injector 14, denitrification heat storage body 15, three-way reversing valve 16, combustion-supporting box 2, combustion-supporting box furnace connection port 22, furnace 3. Detailed Implementation
[0029] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.
[0031] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model 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. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0032] Example 1
[0033] Please see Figure 1 This is an ammonia fuel regenerative combustion device, comprising an ammonia fuel regenerative chamber 1 and a combustion-supporting chamber 2, both connected to a furnace 3. The ammonia fuel regenerative chamber 1, at its end furthest from the furnace 3, has a pipe for alternately introducing ammonia fuel and discharging flue gas, and a three-way reversing valve 16 is installed on the pipe. Inside the ammonia fuel regenerative chamber 1, along the direction from the furnace 3 towards the three-way reversing valve 16, are sequentially arranged an ammonia cracking regenerative body 13, a denitrification reducing agent injector 14, and a denitrification regenerative body 15. The porosity of both the ammonia cracking regenerative body 13 and the denitrification regenerative body 15 gradually decreases along the flue gas outflow (ammonia inflow) direction. The combustion-supporting chamber 2, at its end furthest from the furnace 3, has a combustion-supporting gas inlet. The ceramic framework of the ammonia cracking regenerative body 13 carries an ammonia cracking catalyst, and the ceramic framework of the denitrification regenerative body 15 carries an SCR reduction catalyst. The ammonia cracking catalyst comprises one or more combinations of iron-based, rhodium-based, palladium-based, and molybdenum-based materials to construct active sites that enhance ammonia adsorption energy.
[0034] At least two connecting ports 12 and 22 are provided on the side wall of the furnace 3. The ammonia fuel heat storage box 1 and the combustion-supporting box 2 are respectively fastened to the connecting ports 12 and 22, and the ammonia fuel heat storage box 1 and the combustion-supporting box 2 are connected to the furnace 3 through the connecting ports 12 and 22.
[0035] Example 2
[0036] Based on Embodiment 1, the denitrification reducing agent injector 14 penetrates the shell 11 of the ammonia fuel heat storage tank 1, and a flow control valve is provided on the denitrification reducing agent injector 14. The angle of the denitrification reducing agent injector 14 on the shell 11 is adjustable to facilitate adjustment of the injection angle of the denitrification reducing agent.
[0037] During the heat storage process, the denitrification reducing agent injector 14 injects denitrification reducing agent into the area between the ammonia cracking heat storage body 13 and the denitrification heat storage body 15. The injection angle and injection volume are determined according to the flue gas temperature and NO. x Concentration adjustment.
[0038] The three-way reversing valve 16 is connected to a flue gas pipe and an ammonia fuel inflow pipe, and valves are installed on the flue gas pipe and the ammonia fuel inflow pipe respectively.
[0039] Example 3
[0040] Based on Example 2, the porosity of the heat storage body at the flue gas inflow end of the ammonia cracking heat storage body 13 is 70%–75%, and the porosity at the flue gas outflow end is 60%–65%. The porosity of the entire ammonia cracking heat storage body 13 decreases from large to small along the flue gas outflow (ammonia inflow) direction. Similarly, the porosity of the heat storage body at the flue gas inflow end of the denitrification heat storage body 15 is 55%–60%, and the porosity at the flue gas outflow end is 45%–50%. The porosity of the entire denitrification heat storage body 15 also decreases from large to small along the flue gas outflow (ammonia inflow) direction.
[0041] The working principle of this utility model is as follows:
[0042] A cycle includes an ammonia fuel preheating process and a flue gas heat storage process. The heat storage ceramic skeleton is loaded with an ammonia cracking catalyst and an SCR catalyst. The porosity of the heat storage is designed to gradually change along the gas flow direction.
[0043] Ammonia fuel preheating process:
[0044] The three-way reversing valve 16 closes the exhaust valve and opens the ammonia fuel inflow valve. The flow control valve before the denitrification reducing agent injector 14 is closed, and the ammonia fuel flows into the ammonia fuel heat storage tank 1. It flows sequentially through the area between the denitrification heat storage body 15 and the ammonia cracking heat storage body 13, the denitrification heat storage body 15 and the ammonia cracking heat storage body 13. After being heated by the denitrification heat storage body 15 after the previous cycle of heat storage, the ammonia gas flows through the ammonia cracking heat storage body 13, where the porosity gradually increases, at 780℃~820℃. It is further preheated to 950℃~1050℃ in the ammonia cracking heat storage body 13 and undergoes a cracking reaction to be converted into hydrogen gas. Since higher temperatures result in higher catalytic efficiency, a smaller contact area is required to maintain a constant reaction rate. Simultaneously, higher temperatures lead to lower gas density. To ensure constant flow resistance, the gas flow area needs to gradually increase to reduce flow velocity and compensate for the decrease in density on resistance. By placing an ammonia cracking regenerator 13 with gradually increasing porosity along the ammonia flow direction (where ammonia temperature gradually increases), both the gas-catalyst contact area and the gas flow area can be gradually reduced. This optimizes the ammonia flow resistance distribution and the cracking reaction rate distribution, improving the catalytic efficiency of the ammonia cracking reaction while maintaining constant flow resistance. After passing through the ammonia cracking regenerator 13, all ammonia is converted into a hydrogen-nitrogen mixture. This mixture is injected into the furnace 3 through the fuel-side furnace connection port 12 and mixed with combustion-supporting fuel gas, converting ammonia into a hydrogen-nitrogen mixture. The combustion rate is moderate, the flame is stable, and the flue gas after combustion contains no CO2.
[0045] Flue gas heat storage process:
[0046] The three-way reversing valve 16 opens the exhaust valve and closes the ammonia fuel inflow valve. The flow control valve before the denitrification reducing agent injector 14 opens, and the flue gas flows into the ammonia fuel heat storage box 1 through the furnace connection port 12 of the fuel side box. It flows through the ammonia cracking heat storage body 13 and exchanges heat with it, storing the sensible heat of the flue gas on the ammonia cracking heat storage body 13. In the area between the ammonia cracking heat storage body 13 and the denitrification heat storage body 15, it mixes with the reducing agent sprayed from the denitrification reducing agent injector 14. The injection angle and injection amount of the reducing agent are adjusted online according to the flue gas temperature and nitrogen oxide concentration. When the flue gas temperature is about 430℃~470℃, it flows through the denitrification heat storage body 15 with gradually decreasing porosity and exchanges heat with the denitrification heat storage body 15, storing the sensible heat of the flue gas on the denitrification heat storage body 15 and undergoing a denitrification reaction. Since catalytic efficiency decreases with lower temperatures, a larger contact area is required to maintain a constant reaction rate. Simultaneously, lower temperatures result in higher gas density. To ensure constant flow resistance, the gas flow area needs to gradually decrease. By installing a denitrification heat storage body with gradually decreasing porosity along the flue gas flow direction (where flue gas temperature gradually decreases), the contact area between the gas and catalyst can be gradually increased while the gas flow area is gradually decreased. This optimizes the distribution of flue gas flow resistance and denitrification reaction rate, improving the catalytic efficiency of the flue gas denitrification reaction while maintaining constant flow resistance. After passing through the denitrification heat storage body 15, most of the nitrogen oxides in the flue gas are reduced to nitrogen and water. Flue gas meeting pollutant emission standards is discharged from the system through the coal smoke three-way reversing valve 16.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.
Claims
1. An ammonia fuel regenerative combustion device, characterized in that: The ammonia fuel heat storage box (1) and the combustion-supporting gas box (2) are respectively connected to the furnace (3). The ammonia fuel heat storage box (1) is provided with a three-way reversing valve (16) at the end away from the furnace (3) for alternating ammonia fuel and flue gas discharge. The ammonia fuel heat storage box (1) is provided with an ammonia cracking heat storage body (13), a denitrification reducing agent injector (14) and a denitrification heat storage body (15) in sequence along the direction from the furnace (3) to the three-way reversing valve (16). The porosity of the ammonia cracking heat storage body (13) and the denitrification heat storage body (15) gradually decreases along the flue gas outflow direction or the ammonia gas inflow direction. The combustion-supporting gas box (2) is provided with a combustion-supporting gas inlet at the end away from the furnace (3).
2. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The furnace (3) has at least two connecting ports on its side wall. The connecting ports include a fuel-side box furnace connecting port (12) and a gas-supporting box furnace connecting port (22). The ammonia fuel heat storage box (1) and the gas-supporting box (2) are respectively fastened to the fuel-side box furnace connecting port (12) and the gas-supporting box furnace connecting port (22). The ammonia fuel heat storage box (1) and the gas-supporting box (2) are connected to the furnace (3) through the fuel-side box furnace connecting port (12) and the gas-supporting box furnace connecting port (22).
3. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The denitrification reducing agent injector (14) penetrates the shell (11) of the ammonia fuel heat storage tank (1).
4. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The denitrification reducing agent injector (14) is equipped with a flow control valve.
5. The ammonia fuel regenerative combustion device according to claim 3, characterized in that: The angle of the denitrification reducing agent injector (14) on the housing (11) is adjustable so as to adjust the injection angle of the denitrification reducing agent.
6. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The porosity of the heat storage body at the end where flue gas flows in (13) is 70%~75%, and the porosity of the heat storage body at the end where flue gas flows out is 60%~65%. The porosity of the entire ammonia cracking heat storage body (13) decreases from large to small along the flue gas outflow direction or the ammonia inflow direction.
7. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The ammonia cracking heat storage body (13) has an ammonia cracking catalyst loaded on its ceramic skeleton.
8. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The three-way reversing valve (16) is connected to a flue pipe and an ammonia fuel inflow pipe, and valves are provided on the flue pipe and the ammonia fuel inflow pipe respectively.
9. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The porosity of the heat storage body at the end where flue gas flows in (15) is 55%~60%, and the porosity of the heat storage body at the end where flue gas flows out is 45%~50%. The porosity of the entire heat storage body (15) decreases from large to small along the direction of flue gas outflow or ammonia inflow.
10. The ammonia fuel regenerative combustion device according to claim 1, characterized in that: The ceramic framework of the denitrification heat storage body (15) is loaded with an SCR reduction catalyst.