Efficient self-heating ammonia decomposition hydrogen production reactor

Abstract

The invention discloses an efficient self-heating ammonia decomposition hydrogen production reactor in the technical field of ammonia hydrogen production. Comprising a combustion tail gas outlet, a heat preservation layer shell, a reaction layer shell, a spiral baffle plate, a combustion chamber shell, a spiral combustion-supporting gas pipe, a heat preservation layer, a reaction layer, a combustion chamber, an inclined opening, an ammonia decomposition inlet, an ammonia combustion inlet, a combustion-supporting gas inlet, a decomposition gas outlet, a baffle seat, a tail gas communication port, a decomposition gas collecting pipe and a decomposition gas collecting chamber. The reaction layer shell is nested in the insulating layer shell, an insulating layer is formed between the reaction layer shell and the insulating layer shell, the combustion chamber shell is nested in the reaction layer shell, and a reaction layer is formed between the combustion chamber shell and the reaction layer shell. Ammonia is used as a main fuel, hydrogen is used as an ignition fuel, and ammonia and hydrogen are mixed and combusted in the combustion chamber to provide heat for ammonia decomposition reaction, so that self-heating ammonia decomposition hydrogen production is realized. The three-layer nested structure is adopted, and the advantages of being compact in structure, high in energy utilization rate and the like are achieved.

Description

Technical Field

[0001] The present invention relates to a reactor in the technical field of ammonia decomposition for hydrogen production, and particularly to a highly efficient self-heating ammonia decomposition for hydrogen production reactor with a compact structure. Background Art

[0002] The development of green ammonia for hydrogen production and the integration of ammonia and hydrogen are the definite paths for the development of hydrogen energy and industrial carbon reduction in China. The production capacity of green ammonia has been greatly improved. Liquid hydrogen storage and transportation technologies include distributed ammonia decomposition for hydrogen production technology integrated with filling mother stations, hydrogen / ammonia co-firing for clean and efficient combustion, and other ammonia-related technologies. At the same time, expanding major application scenarios for hydrogen energy remains a major challenge for the development of the hydrogen energy industry. To solve the major technical problems of large-scale, low-cost, high-safety, low-energy-consumption, and large-scale storage and transportation of hydrogen energy, it is urgent to develop large-scale, low-cost, miniaturized, and low-energy-consumption efficient ammonia production, hydrogenation, and hydrogen utilization systems.

[0003] The self-heating ammonia decomposition for hydrogen production reactor is a key component to solve the problems at the hydrogen storage and utilization end of liquid ammonia. Although there is already a certain research foundation at home and abroad, commercial and industrial applications have not yet been formed. Therefore, to promote the implementation of ammonia-hydrogen fuel, a highly efficient miniaturized self-heating ammonia decomposition for hydrogen production reactor is needed.

[0004] In the prior art, there is a patent for invention with the publication number CN115432666A and the name of self-heating ammonia decomposition for hydrogen production device. This device includes an ammonia decomposition for hydrogen production unit and a heat supply unit for supplying heat to the ammonia decomposition for hydrogen production unit. The heat supply unit includes an ammonia self-heating reactor, which has an oxidation reaction chamber for carrying out ammonia oxidation reaction, a reaction gas inlet and a mixed gas outlet connected to the oxidation reaction chamber. The reaction gas inlet is used to input a mixed gas of ammonia and air into the oxidation reaction chamber, and the mixed gas outlet is used to discharge the mixed gas generated by the ammonia oxidation reaction.

[0005] This invention uses ammonia combustion as the heat source for the ammonia decomposition reaction. However, this invention has the following deficiencies: First, ammonia is difficult to be directly ignited; second, the structure of this device is a relatively slender tube, and it is impossible to achieve a high hydrogen production rate under size constraints; third, the high-temperature tail gas after combustion is directly discharged, and there is room for further improvement in energy utilization efficiency. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention proposes a highly efficient self-heating ammonia decomposition for hydrogen production reactor, which uses ammonia as the main fuel and hydrogen as the pilot fuel. Ammonia and hydrogen are mixed and burned in the combustion chamber to provide heat for the ammonia decomposition reaction, thereby realizing self-heating ammonia decomposition for hydrogen production. The present invention adopts a three-layer nested structure, and uses the tail gas after combustion to maintain the outside ambient temperature and further supply heat for the ammonia decomposition reaction, so as to achieve the effects of compact structure and high energy utilization efficiency.

[0007] The present invention is realized through the following technical solutions. The present invention includes a combustion exhaust gas outlet, a thermal insulation layer housing, a reaction layer housing, a spiral baffle, a combustion chamber housing, a spiral combustion-aiding gas pipe, a thermal insulation layer, a reaction layer, a combustion chamber, an inclined opening, an ammonia decomposition inlet, an ammonia combustion inlet, a combustion-aiding gas inlet, a decomposed gas outlet, a baffle seat, an exhaust gas communication port, a decomposed gas collecting pipe, and a decomposed gas collecting chamber. The reaction layer housing is nested within the thermal insulation layer housing, and a thermal insulation layer is formed between the two. The combustion chamber housing is nested within the reaction layer housing, and a reaction layer is formed between the two. The interior of the combustion chamber housing is the combustion chamber. The thermal insulation layer and the combustion chamber are connected through the exhaust gas communication port. The ammonia combustion inlet is connected to the combustion chamber, and the combustion exhaust gas outlet is connected to the thermal insulation layer. The high-temperature exhaust gas after ammonia-hydrogen mixed combustion enters the thermal insulation layer through the exhaust gas communication port to maintain the temperature outside the reaction layer and further supply heat for the ammonia decomposition reaction. A mixture of ammonia and air is introduced into the ammonia fuel inlet. The ammonia decomposition inlet is connected to the reaction layer, the reaction layer is connected to the decomposed gas collecting pipe, the decomposed gas collecting pipe is connected to the decomposed gas collecting chamber, and the decomposed gas collecting chamber is connected to the decomposed gas outlet. After ammonia enters the ammonia decomposition inlet, it decomposes into hydrogen and nitrogen under heat and catalytic action in the reaction layer, and then is collected in the decomposed gas collecting chamber through the decomposed gas collecting pipe, and finally is led out from the decomposed gas outlet. The spiral baffle is approximately continuously distributed in the reaction layer and closely adheres to the combustion chamber housing, with a very small gap between it and the reaction layer housing. The spiral baffle has a very thin break every 90°, so that the material will not be extruded and deformed when heated and expanded. After ammonia enters the reaction layer, it spirally rises along the path arranged by the spiral baffle, increasing the gas flow path and enabling ammonia to be fully heated and decomposed. The spiral combustion-aiding gas pipe is located in the combustion chamber, closely adheres to the inner wall of the combustion chamber housing, and is connected to the combustion-aiding gas inlet. Oblique openings are evenly distributed on the spiral combustion-aiding gas pipe every 90°. The combustion-aiding gas inlet is connected to the combustion chamber through the oblique openings. The connecting line between the oblique opening and the axis of the cylindrical housing forms an angle of 45°, enabling the combustion-aiding gas to be fully mixed with ammonia and better assisting combustion. Part of the decomposed gas generated by ammonia decomposition can be directly introduced into the combustion-aiding gas inlet as the combustion-aiding gas. The baffle seat is located in the reaction layer and is close to one end of the ammonia decomposition inlet. A net-shaped annular baffle for blocking the catalyst is placed on the baffle seat to prevent the catalyst from escaping from the ammonia decomposition inlet. In the reaction layer, granular catalysts beneficial to the ammonia decomposition reaction are filled in the areas of the spiral baffle and the baffle seat. The Ru-based ammonia decomposition catalyst is adopted, and the ammonia decomposition rate can reach more than 99% at 450°C.

[0008] Further, in the present invention, there are 6 decomposed gas collecting pipes, which are evenly distributed circumferentially.

[0009] Furthermore, in the present invention, the thermal insulation layer housing is coated with a cotton thermal insulation material for heat insulation.

[0010] Furthermore, in the present invention, thermocouples for measuring temperature are arranged both in the reaction layer and in the combustion chamber. Among them, the thermocouple in the reaction layer is located in the catalyst between the spiral baffles, and the thermocouple in the combustion chamber is close to the exhaust gas connection port, which is used to calculate the intake air volume of the combustion gas for control.

[0011] Furthermore, in the present invention, all steel materials adopt 316L type corrosion-resistant stainless steel.

[0012] Furthermore, in the present invention, the overall length of the reactor is 740 mm, and the outermost circumferential diameter is 520 mm.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] First, the structure of the reactor device is compact, integrating combustion, reaction, and heat preservation. On the premise of ensuring the ammonia decomposition efficiency, the size of the reactor is reduced as much as possible, and the hydrogen production rate per unit volume is increased, enabling the device to be applied to mobile ammonia decomposition for hydrogen production, such as providing blended fuel hydrogen for engines on ammonia fuel ships.

[0015] Second, high combustion performance. By using ammonia-hydrogen blended combustion, the problem of difficult ammonia combustion is solved while saving the amount of hydrogen used. At the same time, a spiral combustion-aid gas pipeline is adopted, enabling hydrogen to better ignite ammonia at various positions, especially near the pipe wall, ensuring stable and complete combustion of ammonia to supply heat for the ammonia decomposition reaction.

[0016] Third, high energy utilization efficiency. Ammonia-hydrogen blended combustion directly supplies heat for the ammonia decomposition reaction, and the high-temperature combustion exhaust gas is further used for heat preservation and heating outside the reaction layer, making full use of the heat generated by combustion.

[0017] Fourth, high efficiency and high yield. Ammonia spirally ascends in the decomposition layer, increasing the gas flow path, enabling ammonia to be fully heated and decomposed, and with efficient heating from both sides, the device can obtain a large hydrogen production rate, and the hydrogen production rate per unit volume can reach 50 Nm 3 / (m 3 h), meeting the hydrogen demand for mobile applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall and internal three-dimensional structure of an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of the internal sectional structure of an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of the axial sectional structure of an embodiment of the present invention;

[0021] In the figure, 1 is the combustion exhaust gas outlet, 2 is the heat insulation layer housing, 3 is the reaction layer housing, 4 is the spiral baffle, 5 is the combustion chamber housing, 6 is the spiral combustion-aiding gas pipe, 7 is the heat insulation layer, 8 is the reaction layer, 9 is the combustion chamber, 10 is the diagonal opening, 11 is the ammonia decomposition inlet, 12 is the ammonia combustion inlet, 13 is the combustion-aiding gas inlet, 14 is the decomposed gas outlet, 15 is the baffle seat, 16 is the exhaust gas connection port, 17 is the decomposed gas collecting pipe, and 18 is the decomposed gas collecting chamber. Detailed implementation manners

[0022] To make the content of the present invention easier to understand, the technical solution of the present invention will be further explained below in conjunction with specific implementation manners. The examples are only used to illustrate the present invention, but the present invention is not limited to this content. For the operation methods without specific conditions noted in the following examples, they are usually carried out according to conventional conditions or according to the product specifications. The chemical reagents without the manufacturer noted are all conventional drugs that meet the national standards and can be purchased on the market.

[0023] Embodiment

[0024] Such as Figures 1 to 3As shown in the figure, the present invention includes a combustion exhaust gas outlet 1, a thermal insulation layer housing 2, a reaction layer housing 3, a spiral baffle 4, a combustion chamber housing 5, a spiral combustion assisting gas pipe 6, a thermal insulation layer 7, a reaction layer 8, a combustion chamber 9, an inclined opening 10, an ammonia decomposition inlet 11, an ammonia combustion inlet 12, an assisting gas inlet 13, a decomposition gas outlet 14, a baffle seat 15, an exhaust gas communication port 16, a decomposition gas collecting pipe 17, and a decomposition gas collecting chamber 18. The reaction layer housing 3 is nested inside the thermal insulation layer housing 2, and a thermal insulation layer 7 is formed between the two. The combustion chamber housing 5 is nested inside the reaction layer housing 3, and a reaction layer 8 is formed between the two. The inside of the combustion chamber housing 5 is a combustion chamber 9. The thermal insulation layer 7 and the combustion chamber 9 are connected through the exhaust gas communication port 16. The ammonia combustion inlet 12 is connected to the combustion chamber 9, and the combustion exhaust gas outlet 1 is connected to the thermal insulation layer 7. The high-temperature exhaust gas after ammonia-hydrogen mixed combustion enters the thermal insulation layer through the exhaust gas communication port 16 to maintain the temperature outside the reaction layer 8 and further supply heat for the ammonia decomposition reaction. A mixture of ammonia and air is introduced into the ammonia combustion inlet 12. The ammonia decomposition inlet 11 is connected to the reaction layer 8. The reaction layer 8 is connected to the decomposition gas collecting pipe 17. The decomposition gas collecting pipe 17 is connected to the decomposition gas collecting chamber 18. The decomposition gas collecting chamber 18 is connected to the decomposition gas outlet 14. After ammonia enters the ammonia decomposition inlet 11, it decomposes into hydrogen and nitrogen under the action of heat and catalyst in the reaction layer 8, and then is collected into the decomposition gas collecting chamber 18 through the decomposition gas collecting pipe 17, and finally is led out from the decomposition gas outlet 14. The spiral baffle 4 is approximately continuously distributed in the reaction layer 8 and closely adheres to the combustion chamber housing 5, with a very small gap between it and the reaction layer housing 3. The spiral baffle 4 has a very thin break every 90°, so that the material will not be extruded and deformed when heated and expanded. After ammonia enters the reaction layer 8, it spirally rises along the layout path of the spiral baffle 4, increasing the gas flow path and enabling ammonia to be fully heated and decomposed. The spiral combustion assisting gas pipe 6 is located inside the combustion chamber 9, closely adheres to the inner wall of the combustion chamber housing 5, and is connected to the assisting gas inlet 13. The inclined openings 10 are evenly distributed on the spiral combustion assisting gas pipe 6 every 90°. The assisting gas inlet 13 is connected to the combustion chamber 9 through the inclined openings 10. The connecting line between the inclined opening 10 and the axis of the cylindrical housing forms an angle of 45°, enabling the combustion assisting gas to be fully mixed with ammonia and better assisting combustion. Part of the decomposition gas generated by ammonia decomposition can be directly introduced into the assisting gas inlet 13 as the combustion assisting gas. The baffle seat 15 is located inside the reaction layer 8 and is close to one end of the ammonia decomposition inlet 11. A mesh annular baffle for blocking the catalyst is placed on the baffle seat 15 to prevent the catalyst from escaping from the ammonia decomposition inlet 11. Inside the reaction layer 8, granular catalysts beneficial to the ammonia decomposition reaction are filled in the areas of the spiral baffle 4 and the baffle seat 15. There are 6 decomposition gas collecting pipes 17, which are evenly distributed circumferentially. The thermal insulation layer housing 2 is coated with a cotton thermal insulation material for heat insulation. Thermocouples for measuring temperature are arranged inside both the reaction layer 8 and the combustion chamber 9. Among them, the thermocouple in the reaction layer 8 is located in the catalyst between the spiral baffles 4, and the thermocouple in the combustion chamber 9 is close to the exhaust gas communication port 16, and is used to calculate the intake amount of the combustion gas for control.The overall length of the reactor is 740 mm, and the outermost circumferential diameter is 520 mm. All steel materials are made of 316L corrosion-resistant stainless steel.

[0025] In the implementation process of the present invention, ammonia is used as the main fuel, and hydrogen is used as the pilot fuel. Ammonia and hydrogen are mixed and burned in the combustion chamber 9 to provide heat for the ammonia decomposition reaction, thereby realizing self-heating ammonia decomposition to produce hydrogen. The present invention adopts a three-layer nested structure, and the combustion exhaust gas is used to maintain the outer environmental temperature and further heat the ammonia decomposition reaction, so as to achieve the effects of compact structure and high energy utilization rate. The granular catalyst uses Ru-based ammonia decomposition catalyst, and the ammonia decomposition rate can reach more than 99% at 450 °C.

[0026] The above are only the preferred embodiments of the present invention. Any equivalent changes and modifications made by those skilled in the art within the scope of the patent application of the present invention also fall within the scope covered by the appended claims of the present invention.

Claims

1. An efficient self-heating ammonia decomposition hydrogen production reactor, characterized in that: It comprises a combustion tail gas outlet (1), a heat-insulating layer shell (2), a reaction layer shell (3), a spiral baffle (4), a combustion chamber shell (5), a spiral combustion-supporting pipe (6), a heat-insulating layer (7), a reaction layer (8), a combustion chamber (9), an oblique opening (10), an ammonia decomposition inlet (11), an ammonia combustion inlet (12), a combustion-supporting gas inlet (13), a decomposition gas outlet (14), a baffle seat (15), a tail gas communication port (16), a decomposition gas collection pipe (17), and a decomposition gas collection chamber (18); The reaction layer shell (3) is nested in the insulation layer shell (2), forming an insulation layer (7) therebetween; the combustion chamber shell (5) is nested in the reaction layer shell (3), forming a reaction layer (8) therebetween; the combustion chamber shell (5) contains a combustion chamber (9); the insulation layer (7) and the combustion chamber (9) are connected via an exhaust gas connection port (16); the ammonia combustion inlet (12) is connected to the combustion chamber (9); and the combustion exhaust gas outlet (1) is connected to the insulation layer (7); The ammonia decomposition inlet (11) is connected to the reaction layer (8), the reaction layer (8) is connected to the decomposition gas collection pipe (17), the decomposition gas collection pipe (17) is connected to the decomposition gas collection chamber (18), and the decomposition gas collection chamber (18) is connected to the decomposition gas outlet (14); the spiral baffles (4) are continuously distributed in the reaction layer (8) and are closely attached to the combustion chamber shell (5), with a small gap between them and the reaction layer shell (3), and the spiral baffles (4) have a fracture every 90 degrees; The spiral combustion-supporting pipe (6) is located in the combustion chamber (9), closely attached to the inner wall of the combustion chamber shell (5), and is connected to the combustion-supporting gas inlet (13). The spiral combustion-supporting pipe (6) has oblique openings (10) evenly distributed every 90°. The combustion-supporting gas inlet (13) is connected to the combustion chamber (9) through the oblique openings (10). The line connecting the oblique openings (10) and the axis of the cylindrical shell forms an angle of 45°. The baffle seat (15) is located in the reaction layer (8) and close to one end of the ammonia decomposition inlet (11). A mesh annular baffle for blocking the catalyst is placed on the baffle seat (15). In the reaction layer (8), the area of ​​the spiral baffle plate (4) and the baffle seat (15) is filled with a granular catalyst that is beneficial to the ammonia decomposition reaction.

2. The highly efficient self-heating ammonia decomposition hydrogen production reactor according to claim 1 is characterized in that There are 6 decomposition gas collecting pipes (17) in total, which are evenly distributed in the circumferential direction.

3. The highly efficient self-heating ammonia decomposition hydrogen production reactor according to claim 1 is characterized in that The thermal insulation layer shell (2) is coated with a cotton thermal insulation material for heat insulation.

4. The highly efficient self-heating ammonia decomposition hydrogen production reactor according to claim 1 is characterized in that Thermocouples for measuring temperature are arranged in the reaction layer (8) and the combustion chamber (9), wherein the thermocouple in the reaction layer (8) is located in the catalyst between the spiral baffles (4), and the thermocouple in the combustion chamber (9) is close to the exhaust gas connection port (16).

5. The highly efficient autothermal ammonia decomposition hydrogen production reactor according to claim 1 is characterized in that The particle catalyst adopts a Ru-based ammonia decomposition catalyst.

6. The highly efficient self-heating ammonia decomposition hydrogen production reactor according to claim 1 is characterized in that The overall length of the reactor is 740 mm, and the outermost circumference diameter is 520 mm.

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