Hydrogen group decomposition ammonia reburner and combustion method

Abstract

The invention relates to the field of combustors, in particular to a hydrogen-based decomposition ammonia recombustor which comprises a preheating decomposition combustion chamber, and a cavity is formed in the preheating decomposition combustion chamber. The Brown gas pipe penetrates through the chamber wall of the preheating and decomposing combustion chamber, and the output end is arranged inside the cavity; the first igniter penetrates through the chamber wall of the preheating decomposition combustion chamber, and an ignition head of the first igniter is close to the output end of the Brown gas pipe. The output end of the ammonia gas pipe is communicated with the interior of the cavity; the input end of the conveying pipe is communicated with the inner cavity of the preheating decomposition combustion chamber; an ignition head of the second igniter is close to the output end of the conveying pipeline. According to the combustor, active free radicals generated by hydrogen flames serve as catalysts, and by adjusting the proportion and combustion conditions of hydrogen-oxygen mixed gas generated by electrolyzing water and fuel ammonia gas, combustion of the ammonia gas is converted into combustion of hydrogen, nitrogen and possibly undecomposed ammonia gas. The technology aims at improving the combustion efficiency, reducing emission of nitric oxide and improving the overall energy utilization rate. The invention further provides a hydrogen group decomposition ammonia recombustion method.

Description

Technical Field

[0001] The invention relates to the field of burners, in particular to a hydrogen-based decomposition ammonia reburner and a combustion method. Background Art

[0002] As the global demand for energy transformation and green and low-carbon development continues to grow, the potential of hydrogen as a clean energy source is increasingly recognized. Hydrogen does not produce carbon dioxide during combustion and is an important means to achieve a low-carbon economy. However, the storage and transportation of hydrogen remain the main obstacles to its widespread application. In order to solve this problem, ammonia (NH3) has been widely studied as a hydrogen carrier. Ammonia has the advantages of high hydrogen content and easy liquefaction and storage, but there are still challenges in the efficient utilization of ammonia, especially in its decomposition and combustion technology.

[0003] At present, the pre-decomposition combustion technology of ammonia mainly faces the following problems: first, the combustion efficiency of ammonia is low and it is easy to produce harmful emissions such as nitrogen oxides (NOx); second, the decomposition of ammonia usually requires a higher temperature, resulting in increased energy consumption and increased equipment complexity. Therefore, the development of an efficient ammonia burner that can effectively decompose ammonia and achieve clean combustion is the focus of current research. Summary of the invention

[0004] To solve the above problems, the present invention proposes a hydrogen-based ammonia decomposition reburner, which uses the active free radicals generated by hydrogen flame as a catalyst, and optimizes the combustion process of ammonia by adjusting the ratio and combustion conditions of the hydrogen-oxygen mixed gas and fuel ammonia generated by water electrolysis. This technology aims to improve combustion efficiency, reduce nitrogen oxide emissions, and improve overall energy utilization. The present invention also proposes a hydrogen-based ammonia decomposition reburning method.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] Hydrogen-based decomposition ammonia reburner, including

[0007] A preheating and decomposing combustion chamber, wherein the preheating and decomposing combustion chamber has a cavity inside;

[0008] A Brownian gas pipe, wherein the Brownian gas pipe passes through the wall of the preheat decomposition combustion chamber and the output end is located inside the cavity;

[0009] A first igniter, wherein the first igniter passes through the wall of the preheat decomposition combustion chamber, and an ignition head of the first igniter is adjacent to an output end of the Brownian gas pipe;

[0010] an ammonia pipe, wherein an output end of the ammonia pipe is in communication with the interior of the cavity;

[0011] A delivery pipeline, the input end of which is in communication with the inner cavity of the preheating decomposition combustion chamber;

[0012] A second igniter, wherein an ignition head of the second igniter is adjacent to an output end of the delivery pipeline.

[0013] Preferably, there are multiple ammonia pipes, the output ends of the ammonia pipes face the Brownian pipes, and the ammonia pipes are distributed in a ring array in the preheating decomposition combustion chamber.

[0014] Preferably, the ammonia pipe is located below the output end of the Brownian pipe.

[0015] Preferably, the interior of the delivery pipeline has a fire-retardant core.

[0016] Preferably, the preheating decomposition combustion chamber is a vertical tubular body with upper and lower ends closed, the Brownian gas pipe is installed at the lower end of the preheating decomposition combustion chamber, and the input end of the conveying pipeline is connected to the upper end of the preheating decomposition combustion chamber.

[0017] Preferably, the top of the preheat decomposition combustion chamber is connected to a tubular gas-mixing combustion chamber, the middle of the gas-mixing combustion chamber has a gas-mixing disk, the middle of the gas-mixing disk has a through hole, the top end of the delivery pipeline is connected to the through hole of the gas-mixing disk, the second igniter is installed in the gas-mixing combustion chamber, and the ignition head of the second igniter is located above the through hole.

[0018] Preferably, the gas-mixing combustion chamber further comprises an air pipe, which is communicated with the interior of the gas-mixing combustion chamber and is located below the gas-mixing disk.

[0019] Preferably, an inverted cup-shaped gas delivery cap is provided at the position corresponding to the through hole of the gas mixing disk, the top surface of the gas delivery cap has a plurality of first gas delivery holes, and the outer peripheral wall of the gas delivery cap is provided with a plurality of second gas delivery holes.

[0020] Preferably, a plurality of vertically penetrating inner oblique holes are provided inside the mixing disk, and the inner oblique holes are arranged in a circular array with the axis of the mixing disk as the center.

[0021] Preferably, the outer peripheral surface of the mixing disk has a plurality of outer grooves vertically penetrating the mixing disk, and the outer grooves and the inner wall of the mixing combustion chamber enclose an outer hole, and the inner holes are distributed in a ring array with the axis of the mixing disk as the center.

[0022] On the other hand, the present invention also proposes a hydrogen-based decomposition and ammonia reburning method, comprising:

[0023] Brown's gas is introduced into a closed space and ignited, ammonia is introduced during the ignition of the Brown's gas, and the ammonia is heated and activated during the combustion of the Brown's gas;

[0024] The product of Brown's gas combustion and high-temperature ammonia are drawn out and combustion-supporting gas is added, and the mixed gas is ignited to achieve the effect of ammonia combustion.

[0025] The beneficial effects of using the present invention are:

[0026] The hydrogen-based ammonia decomposition reburner proposed by the present invention completes Brownian gas combustion in the preheated decomposition combustion chamber, and ammonia is input through the ammonia pipe around the Brownian gas flame. During the Brownian gas combustion process, the ammonia is heated and activated, and the product after the Brownian gas combustion and the high-temperature ammonia are introduced into the mixed gas combustion chamber for ignition to complete the controlled combustion of ammonia. The present invention can significantly improve the application potential of ammonia as a hydrogen energy carrier by realizing efficient hydrogen-ammonia combustion technology, and promote the practical application of hydrogen energy and renewable energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the overall schematic diagram of the hydrogen-based decomposition ammonia reburner.

[0028] Figure 2 for Figure 1 A partial enlarged view of point A in the middle.

[0029] Figure 3 Schematic diagram of the top view of the mixing plate.

[0030] Reference numerals include:

[0031] 10-preheating decomposition combustion chamber, 11-explosion vent, 12-Brown gas pipe, 121-burner nozzle, 13-ammonia gas pipe, 14-first igniter;

[0032] 20-air mixing combustion chamber, 21-air delivery inner cavity, 22-delivery pipeline, 221-fire arrester core, 23-air pipe, 24-air mixing plate, 241-air delivery cap, 242-first air delivery hole, 243-second air delivery hole, 244-inner inclined hole, 245-outer inclined hole, 25-second igniter, 26-flame mouth. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the technical solution more clear, the technical solution is further described in detail below in conjunction with specific implementation methods. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the technical solution.

[0034] In order to solve the problem that the ammonia decomposition process in the prior art is difficult to control, such as Figure 1As shown, a hydrogen-based ammonia decomposition reburner is proposed. Specifically, the hydrogen-based ammonia decomposition reburner includes a preheating decomposition combustion chamber 10 and a gas-mixing combustion chamber 20. The preheating decomposition combustion chamber 10 is a cylindrical tubular structure as a whole. The preheating decomposition combustion chamber 10 is vertically arranged as a whole and has flange structures at the upper and lower ends. The preheating decomposition combustion chamber 10 is sealed by a flange structure, and a Brownian gas pipe 12 is installed at the position of the flange structure. The Brownian gas pipe 12 passes through the Brownian gas pipe 12 and the output end of the Brownian gas pipe 12 is placed inside the preheating decomposition combustion chamber 10. The Brownian gas pipe 12 can stably and continuously output Brownian gas into the preheating decomposition combustion chamber 10, and a burner 121 is arranged at the output end of the Brownian gas pipe 12.

[0035] One to four ammonia pipes 13 are provided on the outer peripheral wall of the preheating decomposition combustion chamber 10, and the ends of the ammonia pipes 13 are welded to the outer peripheral wall of the preheating decomposition combustion chamber 10, and the ammonia pipes 13 are used to stably transport ammonia to the preheating decomposition combustion chamber 10. In this embodiment, there are four ammonia pipes 13, and the four ammonia pipes 13 are arranged in an array with the axis of the preheating decomposition combustion chamber 10 as the center, and the ammonia pipes 13 are arranged radially with the axis of the preheating decomposition combustion chamber 10 as the center.

[0036] Preferably, the ammonia pipe 13 is located lower than the burner 121 .

[0037] An explosion relief port 11 is provided near the upper end of the outer peripheral wall of the preheating decomposition combustion chamber 10, and the explosion relief port 11 is used to relieve pressure and prevent explosion when the pressure in the preheating decomposition combustion chamber 10 is too high. In some embodiments, an observation window sealed with a transparent material, such as a quartz observation window, can also be provided on the outer peripheral wall of the preheating decomposition combustion chamber 10 to facilitate observation of the internal situation of the preheating decomposition combustion chamber 10. A first igniter 14 is also installed on the outer peripheral wall of the preheating decomposition combustion chamber 10, and the ignition head of the first igniter 14 is adjacent to the burner 121, which is used to ignite the Brownian gas so that the Brownian gas burns in the preheating decomposition combustion chamber 10.

[0038] In this embodiment, the gas-mixing combustion chamber 20 is also a tubular structure, and the lower end of the gas-mixing combustion chamber 20 is sealed and connected to the upper end of the preheating decomposition combustion chamber 10 through a flange structure. A partition is provided between the upper end of the preheating decomposition combustion chamber 10 and the lower end of the gas-mixing combustion chamber 20, and the gas-mixing combustion chamber 20 is used to separate the interior of the gas-mixing combustion chamber 20 and the preheating decomposition combustion chamber 10 into two independent cavities.

[0039] In the mixed gas combustion chamber 20, a mixing disc 24 is provided in the middle of the mixed gas combustion chamber 20 near the upper part, a through hole is provided in the middle of the mixing disc 24, the top end of the delivery pipeline 22 is butted with the through hole of the mixing disc 24, the second igniter 25 is installed in the mixed gas combustion chamber 20, and the ignition head of the second igniter 25 is located above the through hole. A delivery pipeline 22 is provided between the mixing disc 24 and the partition, and the delivery pipeline 22 is used to lead the gas in the preheating decomposition combustion chamber 10 to a position near the upper end of the mixed gas combustion chamber 20. A fire-blocking core 221 is provided in the delivery pipeline 22 near the lower end.

[0040] An air pipe 23 is also provided on the outer peripheral wall of the gas-mixing combustion chamber 20. The function of the air pipe 23 is to introduce external air into the air delivery inner cavity 21 of the gas-mixing combustion chamber 20. The position of the air pipe 23 is located below the gas-mixing disk 24. A second igniter 25 is provided above the gas-mixing disk 24 and adjacent to the gas-mixing disk 24. The second igniter 25 is used to ignite the mixed gas output from the delivery pipeline 22. The uppermost end section of the gas-mixing combustion chamber 20 is a flame port 26, which is a reduced diameter section.

[0041] like Figure 2 As shown, an inverted cup-shaped gas delivery cap 241 is provided at the corresponding through hole of the gas mixing disk 24, and the top surface of the gas delivery cap 241 has a plurality of first gas delivery holes 242, and the outer peripheral wall of the gas delivery cap 241 is provided with a plurality of second gas delivery holes 243. A plurality of vertically penetrating inner oblique holes 244 are provided inside the gas mixing disk 24, and the inner oblique holes 244 are distributed in a circular array with the axis of the gas mixing disk 24 as the center.

[0042] Combination Figure 3 As shown, the outer peripheral surface of the mixing disk 24 has a plurality of outer grooves vertically penetrating the mixing disk 24, and the outer grooves and the inner wall of the mixing combustion chamber 20 enclose an outer inclined hole 245, and the inner holes are distributed in a ring array with the axis of the mixing disk 24 as the center.

[0043] In order to ensure that the hydrogen-oxygen mixture can effectively and stably burn in the preheating decomposition combustion chamber 10, the caliber of the burner 121 must be accurately calculated. The molar ratio of the hydrogen-oxygen mixture made by electrolysis of water is H2:O2=2:1, and the flame propagation speed of the hydrogen-oxygen mixture is about 2.0-2.5m / s. According to the burner specifications and the demand for hydrogen by the ammonia decomposition rate, the caliber of the burner 121 needs to be optimized according to the outlet flow rate of the hydrogen-oxygen mixture, the ammonia flow rate and the pressure of the preheating decomposition combustion chamber 10. The outlet flow rate of the hydrogen-oxygen mixture should be greater than its flame propagation speed and less than the blow-out limit of the hydrogen flame to ensure that the hydrogen-oxygen mixture can burn stably. The ammonia flow rate in the preheating decomposition combustion chamber 10 will affect the pressure in the preheating decomposition combustion chamber 10 and the interference of the airflow disturbance on the flame combustion stability. The caliber of the burner 121 needs to be as large as possible while ensuring the stable combustion of the hydrogen-oxygen mixture as much as possible.

[0044] Since hydrogen-oxygen mixed gas is prone to flashback at high temperatures, an anti-flashback device must be introduced in the design. This burner achieves two-level anti-flashback protection by setting a flashback blocker and an anti-flashback device to ensure the safe and stable operation of the burner. The first-level anti-flashback protection is to configure a partition made of stainless steel powder die-casting material between the mixing plate 24 and the burner 121. The partition is made of stainless steel powder die-casting process to achieve first-level anti-flashback protection. The second-level anti-flashback protection adopts a medium-pressure (0.01~10MPa) FA series-316L stainless steel fire-blocking core 221, which is installed in the gas path of the conveying pipeline 22 close to the hydrogen-oxygen combustion gun side to prevent the hydrogen-oxygen combustion gun from failing to prevent flashback along the gas path into the hydrogen-oxygen generator and causing an explosion.

[0045] In order to achieve a decoupled reaction between hydrogen radicals and ammonia, a reaction zone is set above the Brownian gas pipe 12. The overall structure of the reaction zone adopts a cylindrical cavity design, in which the burner 121 of the hydrogen-oxygen combustion gun is located at the lower center of the cylindrical cavity. To ensure sufficient contact between ammonia and the flame, ammonia is introduced horizontally from four ammonia pipes 13 on the side of the cylinder, and these inlets are located below the burner 121. The length of the cylindrical cavity needs to be reasonably designed according to the height of the hydrogen-oxygen flame to avoid the hydrogen flame directly burning the inner wall due to the cavity being too short, causing damage. At the same time, the fluid flow effect during the operation of the burner must also be considered to ensure that the high-speed jet hydrogen flame can effectively entrain ammonia, thereby improving the mixing efficiency of ammonia and hydrogen radicals.

[0046] The length of the preheating decomposition combustion chamber 10 should be fully considered to avoid excessive temperature drop, thereby reducing the combustion efficiency of the high-temperature mixed gas. Figure 2 As shown, a sleeve structure is adopted, in which the inner tube is used to circulate the high-temperature mixed gas, and the outer tube is used to circulate the air required for combustion, so as to realize the swirl flame and improve the combustion efficiency.

[0047] The ignition process of the burner is divided into two stages: ignition of hydrogen-oxygen mixture and ignition of the product after ammonia decomposition. In the closed mixed gas combustion chamber 20, the combustion of hydrogen-oxygen mixture needs to ensure that its concentration is lower than the explosion limit of hydrogen (4.0% to 75.6%) before ignition. To this end, a corresponding flow of air will be introduced into the cylindrical cavity to dilute the hydrogen-oxygen mixture until the ignition is successful. After the ignition is successful, the first igniter 14 is used to electric spark to preheat the entire burner, and the internal temperature of the preheated decomposition combustion chamber 10 reaches above 100°C to ensure that the fuel is fully gasified and quickly ignited. This mechanism can effectively prevent the ignition difficulty or unstable combustion problems that may occur during low-temperature startup. Ammonia is gradually introduced, and the combustion of the hydrogen-oxygen mixed flame is observed through the window. If the flame is extinguished, the gas supply is stopped immediately. When the amount of ammonia introduced reaches the requirement, the electric spark generated by the first igniter 14 is used again to ignite the high-temperature mixture.

[0048] The first igniter 14 and the second igniter 25 use high-voltage electronic ignition devices, which can quickly generate a strong arc to ensure that the hydrogen-oxygen mixture flame is quickly ignited during the startup phase. The system has an adaptive function and can automatically adjust the ignition parameters according to the gas state in the burner to improve the ignition success rate and efficiency.

[0049] The four key technologies of the hydrogen-based decomposition ammonia reburner are designed to improve combustion efficiency and ensure the stability of the combustion process. The efficient and stable combustion of the burner is achieved through the fine design of the hydrogen-oxygen mixture burner, the optimization of the reaction zone structure, the improvement of the burner nozzle design, and the improvement of the ignition and stable combustion mechanism. The integrated intelligent combustion control system monitors the temperature, pressure and gas flow inside the burner in real time. The system can automatically adjust the fuel flow and air supply to maintain a stable combustion state. Through closed-loop control feedback, the system can promptly correct fluctuations in the combustion process to ensure stability and efficiency under various working conditions.

[0050] The above-mentioned hydrogen-based ammonia decomposition reburner is used to implement a hydrogen-based ammonia decomposition reburning method, which includes: introducing Brown's gas into a closed space and igniting the Brown's gas, introducing ammonia during the process of ignition of the Brown's gas, increasing the temperature of the ammonia and activating the ammonia during the combustion of the Brown's gas; drawing out the products of Brown's gas combustion and the products of ammonia decomposition and adding combustion-supporting gas, and igniting the above-mentioned mixed gas to achieve the effect of ammonia decomposition and combustion.

[0051] The chemical reaction of ammonia and hydrogen combustion belongs to a chain reaction, which undergoes chain excitation, propagation and termination. The excitation of the chain requires the action of external factors (heat, high-energy molecular collision). Due to its high dissociation energy (NH bond dissociation energy is about 391kJ / mol), the combustion process of ammonia often faces the problems of low combustion efficiency and high ignition energy. Hydrogen (H2) is an efficient fuel. During its combustion, a series of active free radicals are generated. These free radicals have strong reactivity. The free radicals (H radicals, OH radicals, etc.) generated during the combustion of hydrogen are used as high-energy molecules to effectively participate in the chain reaction of ammonia combustion. Free radicals are atoms or molecules with unpaired electrons, which makes them highly reactive in chemical reactions. The introduction of these chain reaction mechanisms not only reduces the decomposition strength of the NH bond in the NH3 molecule, thereby reducing the activation energy of ammonia decomposition, but also accelerates the process of ammonia conversion into nitrogen and hydrogen.

[0052] The active free radicals and large amounts of heat generated by hydrogen combustion are used to heat other parts of the burner and maintain the continuous decomposition of ammonia. The heat generated by hydrogen combustion not only drives the entire reaction chain, but also provides the energy output required by the system. In the hydrogen-ammonia burner, the exothermic combustion process of hydrogen is combined to form a closed thermal cycle. The heat released by hydrogen combustion compensates for the energy required for ammonia decomposition, while providing additional heat for equipment operation and energy output. In this way, the hydrogen-ammonia burner can efficiently convert ammonia and hydrogen into heat and energy, achieve an efficient combustion process, and reduce NOx emissions.

[0053] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the technical content. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of this patent.

Claims

1. Hydrogen-based decomposition ammonia reburner, characterized by: include A preheating and decomposing combustion chamber, wherein the preheating and decomposing combustion chamber has a cavity inside; A Brownian gas pipe, wherein the Brownian gas pipe passes through the wall of the preheat decomposition combustion chamber and the output end is located inside the cavity; A first igniter, wherein the first igniter passes through the wall of the preheat decomposition combustion chamber, and an ignition head of the first igniter is adjacent to an output end of the Brownian gas pipe; an ammonia pipe, wherein an output end of the ammonia pipe is in communication with the interior of the cavity; A delivery pipeline, the input end of which is in communication with the inner cavity of the preheating decomposition combustion chamber; A second igniter, wherein an ignition head of the second igniter is adjacent to an output end of the delivery pipeline.

2. The hydrogen-based decomposition ammonia reburner according to claim 1, characterized in that: There are multiple ammonia pipes, the output ends of the ammonia pipes face the Brownian pipes, and the ammonia pipes are distributed in a ring array in the preheating decomposition combustion chamber, and the ammonia pipes are located below the output ends of the Brownian pipes.

3. The hydrogen-based decomposition ammonia reburner according to claim 1, characterized in that: The delivery pipeline has a fire-retardant core inside.

4. The hydrogen-based decomposition ammonia reburner according to claim 1, characterized in that: The preheating decomposition combustion chamber is a vertical tubular body with upper and lower ends closed, the Brownian gas pipe is installed at the lower end of the preheating decomposition combustion chamber, and the input end of the conveying pipeline is connected to the upper end of the preheating decomposition combustion chamber.

5. The hydrogen-based ammonia decomposition reburner according to any one of claims 1 to 4, characterized in that: The top of the preheating decomposition combustion chamber is connected to a tubular mixed gas combustion chamber, the middle of the mixed gas combustion chamber is provided with a mixed gas disk, the middle of the mixed gas disk is provided with a through hole, the top end of the delivery pipeline is connected to the through hole of the mixed gas disk, the second igniter is installed in the mixed gas combustion chamber, and the ignition head of the second igniter is located above the through hole.

6. The hydrogen-based decomposition ammonia reburner according to claim 5, characterized in that: The gas-mixing combustion chamber further comprises an air pipe, which is communicated with the interior of the gas-mixing combustion chamber and is located below the gas-mixing disk.

7. The hydrogen-based decomposition ammonia reburner according to claim 5, characterized in that: An inverted cup-shaped gas delivery cap is arranged at the position of the gas mixing plate corresponding to the through hole, the top surface of the gas delivery cap has a plurality of first gas delivery holes, and the outer peripheral wall of the gas delivery cap is provided with a plurality of second gas delivery holes.

8. The hydrogen-based decomposition ammonia reburner according to claim 5, characterized in that: A plurality of vertically penetrating inner oblique holes are provided inside the mixing plate, and the inner oblique holes are distributed in a circular array with the axis of the mixing plate as the center.

9. The hydrogen-based decomposition ammonia reburner according to claim 5, characterized in that: The outer peripheral surface of the mixing disc has a plurality of outer grooves vertically penetrating the mixing disc, and the outer grooves and the inner wall of the mixing combustion chamber enclose an outer hole, and the inner holes are distributed in a ring array with the axis of the mixing disc as the center.

10. A method for hydrogen-based decomposition of ammonia and reburning, characterized in that: include Brown's gas is introduced into a closed space and ignited, ammonia is introduced during the ignition of the Brown's gas, and the ammonia is heated and activated during the combustion of the Brown's gas; The products of the decomposition of ammonia by the Brown's gas flame: water vapor, nitrogen, hydrogen and possible undecomposed ammonia are led out of the closed space, mixed with an oxidant, and the mixed gas is ignited to achieve the effect of decomposition and combustion of ammonia.

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