A hydrogen-ammonia combustion system based on ammonia decomposition

Abstract

The present invention is applicable to the technical field of ammonia decomposition and hydrogen production combustion, and provides a hydrogen-doped ammonia combustion system based on ammonia decomposition. The device includes an ammonia storage tank, the ammonia storage tank is connected to a first gas pipe, the first gas pipe is connected to an ammonia decomposition furnace, the ammonia decomposition furnace is connected to a third inlet of a burner through a fifth gas pipe, the ammonia storage tank is connected to a liquid ammonia evaporator through a second gas pipe, the output end of the liquid ammonia evaporator is respectively connected to a seventh gas pipe and an eighth gas pipe, the seventh gas pipe is connected to a second inlet of the burner, the eighth gas pipe is connected to a ninth gas pipe, the two ends of the ninth gas pipe are respectively connected to the output end of a blower and the first inlet of the burner, the fifth gas pipe is connected to a sixth gas pipe, and the sixth gas pipe is connected to the ninth gas pipe, whereby the present invention realizes stable control of combustion through a combination of the first gas pipe, etc.

Description

Technical Field

[0001] The invention is applicable to the technical field of hydrogen production and combustion by decomposing ammonia, and provides a hydrogen-blended ammonia combustion system based on ammonia decomposition. Background Art

[0002] As a highly reactive fuel, hydrogen is considered to be one of the most important green and clean energy sources in the future. H2 has a fast combustion rate and a high heat release rate. The combustion product is only H2O, and there is no CO2 emission. The development of new combustion technologies and equipment using hydrogen as fuel has become a breakthrough in alleviating the global greenhouse effect and energy shortage. Due to the high diffusion characteristics and high reactivity of hydrogen, there are a series of safety issues such as leakage, explosion and flashback during its transportation, storage and combustion process, which is also the key bottleneck in the research and development of hydrogen fuel utilization technology.

[0003] As a low-cost chemical raw material, ammonia has high energy density and octane number, and has the advantages of mature production process, easy liquefaction, easy storage and transportation, and zero carbon emissions of combustion products. As can be seen from the chemical formula NH3, ammonia is a carbon-free hydrogen-rich carrier. When it is completely burned in a pure oxygen environment, the only products are nitrogen and water. Therefore, it is also a clean energy that can be used to replace fossil fuels. In recent years, with the continuous advancement of production technology, the cost of synthetic ammonia has continued to decrease, which provides excellent technical support and economic guarantee for the industrial application of ammonia. However, the application of ammonia as a fuel faces major challenges: the ignition and flame characteristics of NH3, the small flammable range of NH3, the high ignition temperature, the low laminar flame combustion speed and poor stability.

[0004] Therefore, in order to improve the utilization of ammonia in industrial production, it is urgent to solve the problem of stability control during the ammonia combustion process. Summary of the invention

[0005] In view of the above-mentioned defects, the purpose of the present invention is to provide a hydrogen-added ammonia combustion system based on ammonia decomposition, the purpose is to solve the problems in the background, including an ammonia storage tank, the ammonia storage tank is connected to a first air pipe, the first air pipe is connected to an ammonia decomposition furnace, the ammonia decomposition furnace is connected to the third inlet of the burner through a fifth air pipe, the ammonia storage tank is connected to a liquid ammonia evaporator through a second air pipe, the output end of the liquid ammonia evaporator is respectively connected to a seventh air pipe and an eighth air pipe, the seventh air pipe is connected to the second inlet of the burner, the eighth air pipe is connected to a ninth air pipe, the two ends of the ninth air pipe are respectively connected to the output end of the blower and the first inlet of the burner, the fifth air pipe is connected to a sixth air pipe, and the sixth air pipe is connected to the ninth air pipe.

[0006] Furthermore, the fifth air pipe, the sixth air pipe, the seventh air pipe, the eighth air pipe and the ninth air pipe are all installed with regulating valves.

[0007] Furthermore, the ninth air pipe is equipped with a heat exchanger.

[0008] Furthermore, the burner includes a mixing cylinder, a first inlet is provided at one end of the mixing cylinder, a second inlet is provided on the side wall of the mixing cylinder, an ignition cylinder is provided at the other end of the mixing cylinder, an igniter is installed on the side wall of the ignition cylinder, a combustion chamber is provided at the end of the ignition cylinder away from the mixing cylinder, and a third inlet is provided on the side wall of the combustion chamber.

[0009] Furthermore, a dispersion tube is installed in the combustion chamber, and the dispersion tube includes a combustion tube, and a plurality of air inlet holes are arranged on the side wall of the combustion tube. A dispersion surface is arranged at one end of the combustion tube, and a step is arranged on the inner wall of the dispersion surface, and the step is installed on the inner wall of the combustion chamber.

[0010] Furthermore, a plurality of dispersion pipes are installed on the inner wall of the combustion tube, and the dispersion pipes penetrate the dispersion surface and are provided with dispersion holes.

[0011] Furthermore, the outer wall of the combustion tube is axially provided with a first air inlet hole, a second air inlet hole, a third air inlet hole, and a fourth air inlet hole.

[0012] Furthermore, the diameters of the first air inlet hole, the second air inlet hole, the third air inlet hole, and the fourth air inlet hole increase sequentially.

[0013] Furthermore, the first air inlet hole, the second air inlet hole, the third air inlet hole, and the fourth air inlet hole are all distributed in a ring shape along the side wall of the combustion tube, the number of the first air inlet hole and the third air inlet hole is the same, and the number of the second air inlet hole and the fourth air inlet hole is the same.

[0014] Furthermore, a gas distribution hole is provided in the middle of the dispersion pipe.

[0015] Beneficial Effects

[0016] The present invention provides raw materials by connecting the seventh air pipe to the combustion chamber; the eighth air pipe is mixed with the ninth air pipe to achieve pre-mixing of ammonia, which is convenient for subsequent combustion; the sixth air pipe is connected with the ninth air pipe to enhance the mixed concentration of ammonia, oxygen and hydrogen, which is convenient for subsequent combustion; the regulating valve controls the gas flow in each pipeline, so as to accurately control the concentration of different gases during combustion; the first air inlet hole, the second air inlet hole, the third air inlet hole and the fourth air inlet hole realize the concentration control of hydrogen at different positions of the inner wall of the combustion tube, so as to realize full combustion and stable control of the gas in the combustion tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Flow chart of the present invention;

[0018] Figure 2 is an axonometric view of a burner of the present invention;

[0019] Figure 3It is an axonometric view of the dispersion tube of the present invention;

[0020] In the figure, 1-ammonia storage tank, 2-first air pipe, 3-second air pipe, 4-ammonia decomposition furnace, 5-fourth air pipe, 6-fifth air pipe, 7-regulating valve, 8-burner, 81-mixing cylinder, 82-first inlet, 83-second inlet, 84-ignition cylinder, 85-lighter, 86-combustion chamber, 87-third inlet, 9-liquid ammonia evaporator, 10-sixth air pipe, 11-seventh air pipe, 12-eighth air pipe, 13-blower, 14-ninth air pipe, 15-heat exchanger, 16-dispersion cylinder, 17-combustion cylinder, 18-first air inlet hole, 19-second air inlet hole, 20-third air inlet hole, 21-fourth air inlet hole, 22-dispersion surface, 23-dispersion pipe, 24-dispersion hole, 25-dispersion hole, 26-step. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] See also Figure 1-3 The object of the present invention is to provide a hydrogen-ammonia combustion system based on ammonia decomposition, comprising an ammonia storage tank 1, which is connected to an ammonia decomposition furnace 4 through a first gas pipe 2. The ammonia decomposition furnace 4 first gasifies liquid ammonia and converts it into gaseous ammonia, and then heats the gaseous ammonia under the action of a catalyst. The catalyst is a mixed powder of MgO, NiO, and MoO2, and the weight percentages of MgO, NiO, and MoO2 are 30%, 30%, and 40%, respectively. These catalysts have high catalytic activity and selectivity, and can promote the progress of ammonia decomposition reaction under relatively mild conditions, accelerate the rate of ammonia decomposition reaction and reduce the reaction temperature, thereby reducing the reaction condition requirements and reducing energy and waste consumption under the premise of maintaining the reaction chemical formula and chemical equilibrium. The reaction temperature is 850°C. After the liquid ammonia is decomposed, it is cooled by a heat exchanger and a cooler inside the ammonia decomposition furnace 4 to obtain hydrogen and nitrogen. The nitrogen is discharged from the fourth gas pipe 5, and the hydrogen is connected to the third inlet 87 of the combustion chamber 86 from the fifth gas pipe 6.

[0023] The ammonia storage tank 1 is connected to the liquid ammonia evaporator 9 through the second air pipe 3. After the liquid ammonia enters the liquid ammonia evaporator 9, it is affected by the heat of the outside air and water, and the temperature of the liquid ammonia gradually increases, and the liquid ammonia begins to evaporate into a gaseous state. As the liquid ammonia evaporates, the formed ammonia gas gradually fills the entire output pipeline of the liquid ammonia evaporator 9. The output pipeline of the liquid ammonia evaporator 9 is respectively connected to the seventh air pipe 11 and the eighth air pipe 12 through a three-way pipe, and the seventh air pipe 11 is connected to the second inlet 83 of the combustion chamber 86.

[0024] The output end of the blower 13 is connected to the ninth air pipe 14, and the ninth air pipe 14 is equipped with a heat exchanger 15 to increase the temperature and facilitate the subsequent combustion process. The ninth air pipe 14 is connected to the first inlet 82 of the combustion chamber 86, the ninth air pipe 14 is connected to the eighth air pipe 12 through a tee, the fifth air pipe 6 is connected to the sixth air pipe 10 through a tee, and the sixth air pipe 10 is connected to the ninth air pipe 14 through a tee. The reaction equation in the combustion chamber 86 is: 3H2+2NH3+5O2→6H2O+2NO2.

[0025] The device used in the hydrogen-ammonia combustion system based on ammonia decomposition includes a burner 8, which includes a mixing cylinder 81. A first inlet 82 is provided at one end of the mixing cylinder 81, and a second inlet 83 is provided on the side wall of the mixing cylinder 81. The first inlet 82 is connected to the ninth gas pipe 14, and the second inlet 83 is connected to the seventh gas pipe 11; an end of the mixing cylinder 81 away from the first inlet 82 is connected to an ignition cylinder 84 by bolts, and the side wall of the ignition cylinder 84 is connected to an igniter 85 by bolts. The igniter 85 is a prior art, and the ignition cylinder 84 is a trumpet-shaped structure, and the angle with the horizontal direction is 45 degrees; a combustion chamber 86 is provided at the end of the ignition cylinder 84 away from the mixing cylinder 81, and a third inlet 87 is provided on the top of the combustion chamber 86.

[0026] A dispersion tube 16 is installed inside the combustion chamber 86. The dispersion tube 16 includes a combustion tube 17. The combustion tube 17 is a hollow cylindrical structure. A dispersion surface 22 is arranged on one side of the combustion tube 17. The dispersion surface 22 is an annular structure. A step 26 is arranged on the inner wall of the dispersion surface 22. The outer wall of the step 26 is connected to the side wall of the combustion chamber 86 by a thread. Dispersion tubes 23 are welded to the inner wall of the combustion tube 17. There are six dispersion tubes 23. One end of the dispersion tube 23 passes through the dispersion surface 22. A dispersion hole 24 is arranged at one end of the dispersion tube 23 close to the step 26. A gas separation hole 25 is arranged in the middle of the dispersion tube 23. The hydrogen in the third inlet 87 passes through the dispersion surface 22 and the dispersion hole 24 to reach the gas separation hole 25 for gas separation, thereby realizing uniform combustion of ammonia, hydrogen and oxygen. The side wall of the combustion tube 17 is provided with a first air inlet hole 18, a second air inlet hole 19, a third air inlet hole 20, and a fourth air inlet hole 21 along the axial direction of the combustion tube 17. The diameters of the first air inlet hole 18, the second air inlet hole 19, the third air inlet hole 20, and the fourth air inlet hole 21 increase successively. When ammonia, hydrogen, and oxygen react, the end of the combustion tube 17 away from the dispersion surface 22 does not burn completely and lacks hydrogen. The first air inlet hole 18, the second air inlet hole 19, the third air inlet hole 20, and the fourth air inlet hole 21 increase successively, which is conducive to the mixing of hydrogen with ammonia and air for full reaction. The first air inlet hole 18, the second air inlet hole 19, the third air inlet hole 20, and the fourth air inlet hole 21 are evenly distributed in a ring shape along the side wall of the combustion tube 17, so that hydrogen is distributed all over the inner wall of the combustion tube 17, which facilitates the full reaction of ammonia, hydrogen, and oxygen.

[0027] Preferably, the number of the first air inlet holes 18 is the same as that of the third air inlet holes 20, the number of the second air inlet holes 19 is the same as that of the fourth air inlet holes 21, and the number of the first air inlet holes 18 is twice that of the second air inlet holes 19. The number of the first air inlet holes 18 is twice that of the second air inlet holes 19. Since the first air inlet holes 18 and the second air inlet holes 19 have small apertures, the amount of hydrogen entering is small at the end of the combustion tube 17 close to the dispersion surface 22, and the combustion is stable; the third air inlet holes 20 and the fourth air inlet holes 21 are far away from the dispersion surface 22 of the combustion tube 17, and the hydrogen content is small. The number of the third air inlet holes 20 is twice that of the fourth air inlet holes 21, which is conducive to the mixing of hydrogen with ammonia and oxygen, thereby making the combustion of ammonia, hydrogen and oxygen stable.

[0028] Preferably, the fifth gas pipe 6, the sixth gas pipe 10, the seventh gas pipe 11, the eighth gas pipe 12, and the ninth gas pipe 14 are all connected with regulating valves 7 by threads to control the flow of gas in the pipeline. The regulating valve 7 of the fifth gas pipe 6 controls the flow of hydrogen into the third inlet 87 of the burner 8. The regulating valve 7 of the seventh gas pipe 11 controls the flow of ammonia into the second inlet 83 of the burner 8. The regulating valve 7 of the sixth gas pipe 10 controls the flow of hydrogen into the ninth gas pipe 14, thereby controlling the concentration of the mixed gas of hydrogen and the ninth gas pipe 14; the regulating valve 7 of the eighth gas pipe 12 controls the flow of ammonia into the ninth gas pipe 14, thereby controlling the concentration of the mixed gas of ammonia and the ninth gas pipe 14.

[0029] To sum up, in actual use, the liquid ammonia in the ammonia storage tank 1 reaches the ammonia decomposition furnace 4 through the first air pipe 2 for decomposition, the nitrogen after the decomposition of the liquid ammonia is released into the air, and the hydrogen reaches the third inlet 87 of the burner 8 through the fifth air pipe 6; the liquid ammonia in the ammonia storage tank 1 produces ammonia in the liquid ammonia evaporator 9, and the ammonia is passed into the second inlet 83 of the burner 8 through the seventh air pipe 11, the blower 13 mixes the air and the ammonia in the eighth air pipe 12, and passes into the first inlet 82 of the burner 8 through the ninth air pipe 14; the hydrogen in the third inlet 87 reaches the inner wall of the dispersion tube 16 in two ways, one way is to mix the hydrogen with the gas on the inner wall of the combustion tube through the gas distribution hole 25 of the dispersion tube 23, and the mixed gas on the inner wall of the combustion tube 17 is mixed to participate in the combustion; the other way reaches the inner wall of the dispersion tube 16 through the first air inlet hole 18, the second air inlet hole 19, the third air inlet hole 20, and the fourth air inlet hole 21, so as to participate in the combustion with the mixed gas on the inner wall of the combustion tube 17.

[0030] Thus, the device can be connected to the combustion chamber 86 through the seventh air pipe 11 to provide raw materials; the eighth air pipe 12 is mixed with the ninth air pipe 14 to achieve pre-mixing of ammonia, which is convenient for subsequent combustion; the sixth air pipe 10 is connected with the ninth air pipe 14 to enhance the mixed concentration of ammonia, oxygen and hydrogen, which is convenient for subsequent combustion; the regulating valve 7 controls the gas flow in each pipeline, so as to accurately control the concentration of different gases during combustion; the first air inlet hole 18, the second air inlet hole 19, the third air inlet hole 20, and the fourth air inlet hole 21 realize the concentration control of hydrogen at different positions of the inner wall of the combustion tube 17, so as to realize full combustion and stable control of the gas in the combustion tube 17.

[0031] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A hydrogen-ammonia combustion system based on ammonia decomposition, characterized by: The invention comprises an ammonia storage tank (1), wherein the ammonia storage tank (1) is connected to a first gas pipe (2), the first gas pipe (2) is connected to an ammonia decomposition furnace (4), the ammonia decomposition furnace (4) is connected to a third inlet (87) of a burner (8) through a fifth gas pipe (6), the ammonia storage tank (1) is connected to a liquid ammonia evaporator (9) through a second gas pipe (3), the output end of the liquid ammonia evaporator (9) is respectively connected to a seventh gas pipe (11) and an eighth gas pipe (12), the seventh gas pipe (11) is connected to a second inlet (83) of the burner (8), the eighth gas pipe (12) is connected to a ninth gas pipe (14), both ends of the ninth gas pipe (14) are respectively connected to an output end of a blower (13) and a first inlet (82) of the burner (8), the fifth gas pipe (6) is connected to a sixth gas pipe (10), the sixth gas pipe (10) is connected to the ninth gas pipe (14); The burner (8) comprises a mixing cylinder (81), one end of the mixing cylinder (81) is provided with a first inlet (82), a side wall of the mixing cylinder (81) is provided with a second inlet (83), the other end of the mixing cylinder (81) is provided with an ignition cylinder (84), an igniter is installed on the side wall of the ignition cylinder (84), one end of the ignition cylinder (84) away from the mixing cylinder (81) is provided with a combustion chamber (86), and a side wall of the combustion chamber (86) is provided with a third inlet (87); A dispersion tube (16) is installed in the combustion chamber (86), the dispersion tube (16) comprising a combustion tube (17), a side wall of the combustion tube (17) being provided with a plurality of air inlet holes, a dispersion surface (22) being provided at one end of the combustion tube (17), an inner wall of the dispersion surface (22) being provided with a step (26), and the step (26) being installed on the inner wall of the combustion chamber (86); A plurality of dispersion pipes (23) are installed on the inner wall of the combustion tube (17); the dispersion pipes (23) penetrate the dispersion surface (22) and are provided with dispersion holes (24); and a gas distribution hole (25) is provided in the middle of the dispersion pipes (23); The outer wall of the combustion cylinder (17) is provided with a first air inlet hole (18), a second air inlet hole (19), a third air inlet hole (20), and a fourth air inlet hole (21) in sequence along the axial direction from the side of the dispersion surface (22) to the side away from the dispersion surface (22); The diameters of the first air inlet hole (18), the second air inlet hole (19), the third air inlet hole (20), and the fourth air inlet hole (21) increase in sequence; The first air inlet holes (18), the second air inlet holes (19), the third air inlet holes (20), and the fourth air inlet holes (21) are all distributed in a ring shape along the side wall of the combustion tube (17); the first air inlet holes (18) and the third air inlet holes (20) are the same in number, and the second air inlet holes (19) and the fourth air inlet holes (21) are the same in number.

2. The hydrogen-ammonia combustion system based on ammonia decomposition according to claim 1 is characterized in that: The fifth air pipe (6), the sixth air pipe (10), the seventh air pipe (11), the eighth air pipe (12), and the ninth air pipe (14) are all installed with regulating valves (7).

3. The hydrogen-blended ammonia combustion system based on ammonia decomposition according to claim 1, characterized in that: The ninth air pipe (14) is equipped with a heat exchanger (15).

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