Multifunctional ammonia decomposition hydrogen production system

Abstract

The invention discloses a multifunctional ammonia decomposition hydrogen production system and belongs to the technical field of clean energy. The system is composed of an electromagnetic induction cold starting subsystem, a thermocatalytic ammonia decomposition subsystem and a power subsystem. In the cold start stage, the electromagnetic induction cold start subsystem performs non-contact heating on a conductive and ferromagnetic catalyst by utilizing a magnetic induction heating technology, and drives the ammonia decomposition reaction in an extremely short time (about 5 seconds). In a normal use stage, the thermocatalytic decomposition ammonia subsystem utilizes an efficient monolithic catalyst at a lower temperature (llt; 500 DEG C) to promote ammonia decomposition and provide stable and sufficient hydrogen supply for the engine. According to the power subsystem and the method for integrating power generation with the hydrogen fuel cell and engine tail gas waste heat recovery, the energy utilization efficiency is improved, and therefore the problems that an electric heater is low in temperature response speed, low in energy utilization rate, low in ammonia decomposition conversion rate and the like are solved; cooperative work of all parts of the system provides powerful support for development of clean energy automobiles.

Description

Technical Field

[0001] The invention belongs to the technical field of clean energy, and in particular relates to a multifunctional ammonia decomposition hydrogen production system. Background Art

[0002] With the increasing global attention to low-carbon and environmentally friendly economic models, zero-carbon economy is gradually becoming the mainstream trend of future economic development. In this context, finding clean and efficient energy carriers has become the key. Ammonia (NH3), as a new type of fuel with low production cost, high storage and transportation safety and high energy density, has good storage and transportation conditions. Due to the relatively low calorific value and combustion rate of ammonia, a fuel with a larger calorific value is required as an ignition agent. By decomposing ammonia to produce hydrogen as an ignition agent, the problem that ammonia itself is not easy to burn can be effectively solved. This not only utilizes ammonia resources, but also takes advantage of the flammable characteristics of hydrogen, thereby achieving a more efficient combustion process.

[0003] Chinese patents CN117797730A and CN117380099A disclose an ammonia decomposition reactor based on the principle of electromagnetic induction. This reactor uses the alternating magnetic field generated by the induction coil to directly heat the reaction chamber made of metal materials, thereby quickly and evenly heating the ammonia inside. Compared with the traditional resistance wire heating method, induction heating technology has shown significant advantages, including faster heating speed, more uniform temperature distribution and higher energy conversion efficiency. However, the system still relies on metal pipes as a heat transfer medium, which to a certain extent causes indirect heat transfer. Summary of the invention

[0004] The purpose of the present invention is to provide a multifunctional ammonia decomposition hydrogen production system to solve the problems of slow temperature response speed of electric heaters, low energy utilization rate and low ammonia decomposition conversion rate. The ammonia decomposition hydrogen production system consists of an electromagnetic induction cold start subsystem, a thermal catalytic decomposition ammonia subsystem and a power subsystem.

[0005] The electromagnetic induction cold start subsystem consists of an ammonia storage device 1, a flow control valve 2, a reactor 3 with a mixed gas outlet 6, a spacer layer 4, an induction coil 5, a high-frequency induction heater 7 and a temperature sensor 8. The thermal catalytic decomposition ammonia subsystem consists of an ammonia decomposition reaction tube 11 placed in a heating chamber 12, and the outside of the heating chamber 12 is wrapped with a thermal insulation layer 13. The heating chamber 12 has a heating gas output port 10 and a heating gas input port 14; the ammonia decomposition reaction tube 11 has a mixed gas inlet 9 and a hydrogen-nitrogen mixed gas outlet 15. The power subsystem consists of a combustion chamber 17, an air supply device 19, an adsorption column 21, a power generation device 22 and an electric inverter 23. The outside of the combustion chamber 17 is wrapped with a waste heat recovery pipeline 18, and the waste heat recovery pipeline 18 has a hot gas outlet 16 and a cold gas inlet 20.

[0006] In the electromagnetic induction cold start subsystem, the ammonia storage device 1 is used to store and provide ammonia, and the flow control valve 2 is installed on the pipeline between the ammonia storage device 1 and the reactor 3 to accurately control the inflow of ammonia in the reactor 3 (3000~36000mL / g cat / h); the reactor 3 adopts a tubular structure made of non-electromagnetic induction materials, and is filled with an efficient ammonia decomposition catalyst to promote the ammonia decomposition reaction. The hydrogen produced after decomposition and the incompletely decomposed ammonia mixture are discharged through the mixed gas outlet 6 and enter the thermal catalytic decomposition ammonia subsystem; the reactor 3 is wrapped with a low thermal conductivity spacer layer 4 with a thickness of no more than 5 cm to maintain the temperature in the reactor 3. The mixed gas outlet 6 is located at the rear end of the reactor 3 to discharge the decomposed hydrogen and the incompletely decomposed ammonia mixture. The induction coil 5 is spirally wound on the outer surface of the spacer layer 4, and the high-frequency induction heater 7 is connected to the induction coil 5. The high-frequency induction heater 7 controls the current of the alternating current, and generates an alternating magnetic field through the induction coil 5 to heat the catalyst in the reactor 3, ensuring that the temperature of the reactor 3 quickly rises to 500-1500°C to promote the ammonia decomposition reaction. The hydrogen produced after decomposition and the incompletely decomposed ammonia mixture are discharged through the mixed gas outlet 6 and enter the thermal catalytic decomposition ammonia subsystem; the high-frequency induction heater 7 is connected to the temperature sensor 8, which is placed at the rear end of the reactor 3 to monitor the temperature change in real time and feedback the signal to the high-frequency induction heater 7.

[0007] In the thermal catalytic decomposition of ammonia subsystem, the mixed gas outlet 6 of the electromagnetic induction cold start subsystem is directly connected to the mixed gas inlet 9 of the ammonia decomposition reaction tube 11; the heating chamber 12 tightly surrounds the ammonia decomposition reaction tube 11, and provides multi-mode heating methods such as electric heating, hot air heating and hydrogen combustion heating to heat the temperature of the ammonia decomposition reaction tube 11 to 400-600°C; specifically, the electric heating is achieved by winding a resistance wire on the outside of the ammonia decomposition reaction tube 11 (the resistance wire is still placed in the heating chamber 12 at this time), and when current passes through these resistance wires, the resistance wire will generate heat due to the resistance effect; the heating chamber 12 is equipped with a heating gas output port 10 and a heating gas input port 14, which are used for hot air heating and hydrogen combustion heating modes. The ammonia decomposition reaction tube 11 is equipped with an integral catalyst (the catalytic process in the reactor 3 is ammonia decomposition, and the reaction products are hydrogen, nitrogen and undecomposed ammonia. The reaction process of the ammonia decomposition reaction tube 11 is consistent with the reaction process in the reactor 3. Since the thermal catalytic decomposition of ammonia subsystem thermal resistance wire and hot air heating start very slowly, an electromagnetic induction cold start subsystem is added to start the ammonia decomposition reaction within 5 seconds. The reason is that electromagnetic induction heating uses a catalyst with high conductivity, good thermal conductivity and ferromagnetic properties, which can achieve a temperature increase of >600°C in 1 second; and the ammonia decomposition reaction tube 11 is equipped with an integral catalyst, which is a high-efficiency catalyst developed for thermal catalytic ammonia decomposition reaction, and the carrier does not have ferromagnetic properties), which promotes thermal catalytic decomposition of ammonia, and the generated hydrogen and nitrogen mixed gas is then guided into the power subsystem through the hydrogen and nitrogen mixed gas outlet 15.

[0008] The power subsystem realizes efficient use of energy by recovering the waste heat generated by the combustion chamber 17 or the electric energy generated by the power generation device 22. The mixed gas output from the hydrogen-nitrogen mixed gas outlet 15 of the ammonia decomposition reaction tube 11 enters the power subsystem and is divided into two parallel branches. The first branch is connected to the combustion chamber 17 and the air supply device 19. The outside of the combustion chamber 17 is wrapped with a waste heat recovery pipeline 18. The two ends of the waste heat recovery pipeline 18 are respectively provided with a hot gas outlet 16 and a cold air inlet 20. The hot gas outlet 16 is connected to the heating gas input port 14 through a pipeline, which is used for heat compensation of the thermal catalytic decomposition ammonia subsystem; the cold air inlet 20 is connected to the heating gas output port 10 through a pipeline; the air supply device 19 is simultaneously connected to the cold air inlet 20 and the combustion chamber 17 inlet, on the one hand for the combustion chamber 17 provides sufficient oxygen supply for the combustion of the mixed gas, thereby supporting the smooth progress of the combustion process; on the other hand, the gas provided by the air supply device 19 enters the waste heat recovery pipeline 18 through the cold air inlet 20. The heat generated by the combustion of the mixed gas inside the combustion chamber 17 can heat the gas in the waste heat recovery pipeline 18 to a higher temperature, and then the hot air is transmitted from the hot gas outlet 16 to the heating gas input port 14 through the pipeline and enters the heating chamber 12, providing the required heat compensation for the thermal catalytic decomposition of ammonia through heat exchange; the cold air after heat exchange is transmitted from the heating gas output port 10 to the cold air inlet 20 through the pipeline and flows back to the waste heat recovery pipeline 18 for circulation. The adsorption column 21, the power generation device 22 and the power inverter 23 are connected in sequence on the second branch. The output end of the power inverter 23 is connected to the heating chamber 12 and the induction coil 5, providing alternating current for the electric heating of the heating chamber 12 and the electromagnetic induction heating of the induction coil 5, so as to achieve efficient use of energy.

[0009] During the cold start phase, the electromagnetic induction cold start subsystem uses magnetic induction heating technology to rapidly heat up the conductive and ferromagnetic catalyst in a non-contact manner, stimulating the ammonia decomposition reaction in a very short time of about 5 seconds. After entering the normal use phase, the thermal catalytic decomposition of ammonia subsystem uses an efficient integral catalyst to effectively promote the decomposition of ammonia at a temperature below 500°C, ensuring a continuous and stable supply of hydrogen to the engine. In addition, the power subsystem significantly improves the energy efficiency of the entire system through the integrated design of power generation and waste heat recovery of the power generation device 22 and the combustion chamber 17. The multifunctional ammonia decomposition hydrogen production system of the present invention not only solves the problems of difficult cold start and high energy consumption of the ammonia decomposition hydrogen production reaction, but also realizes the effective management and recycling of energy through the synergy of multiple systems.

[0010] Furthermore, the reactor 3 in the electromagnetic induction cold start subsystem is made of non-electromagnetic induction materials, such as quartz, ceramic or corundum, and the reactor 3 is a cylindrical structure with an outer diameter of 10 to 100 mm, a wall thickness of 2 to 5 mm, and a length of 100 to 500 mm.

[0011] Furthermore, the reactor 3 in the electromagnetic induction cold start subsystem is filled with an efficient ammonia decomposition catalyst with high electrical conductivity, good thermal conductivity and ferromagnetic properties, which is used for thermal catalytic decomposition of ammonia to produce hydrogen; the catalyst can be a metal oxide catalyst (metal oxides are magnesium oxide, calcium oxide, barium oxide, aluminum oxide, cerium oxide, lanthanum oxide, gadolinium oxide, titanium oxide and zirconium oxide, etc.) loaded with one or more metals (metals such as iron, cobalt, nickel, copper, gold, platinum or ruthenium), a metal-based material catalyst (one or two metals such as iron, cobalt, nickel, manganese or copper) or a carbon-based material catalyst (carbon-based materials are graphite carbon, carbon nanotubes, graphene and graphene oxide, etc.); the efficient ammonia decomposition catalyst can be a powder, granular, columnar, tubular, mesh or sheet structure; it is obtained by loading one or more metal element precursors on metal oxides, metal-based materials or carbon-based materials through impregnation, electrochemical deposition, alkali precipitation, Joule heat in-situ synthesis, hydrothermal, chemical vapor deposition or physical vapor deposition.

[0012] Furthermore, the steps of preparing the catalyst filled in the reactor 3 by the impregnation method are as follows: first, disperse the metal oxide (such as CeO2, TiO2, ZrO2, etc.) or carbon-based material (such as carbon nanotubes CNT, graphene, activated carbon, etc.) in 50 to 5000 ml of water, then add an appropriate amount of metal element precursor, and stir the obtained mixture at room temperature for 1 to 12 hours to ensure uniform dispersion; then, use a rotary evaporator to gradually evaporate the water to obtain a solid powder, and further sinter it at 400 to 600 degrees Celsius in a tubular furnace under a hydrogen atmosphere for 0.5 to 5 hours to obtain a highly efficient ammonia decomposition catalyst. The prepared catalyst has high electrical conductivity, good thermal conductivity and ferromagnetic properties.

[0013] Furthermore, the steps of preparing the catalyst filled in the reactor 3 by alkali precipitation method are as follows: first, disperse the metal oxide (such as CeO2, TiO2, ZrO2, etc.) or carbon-based material (such as carbon nanotube CNT, graphene, activated carbon, etc.) in 50 to 5000 ml of water, add an appropriate amount of metal element precursor, and then stir at room temperature for 1 to 12 hours; then, add alkaline substances (such as one or two of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia water, and sodium borohydride) to promote the precipitation of metal ions; after sufficient precipitation, separate the solid product by filtration, and dry it to obtain an efficient ammonia decomposition catalyst. The prepared catalyst has high electrical conductivity, good thermal conductivity and ferromagnetic properties.

[0014] Furthermore, the steps of preparing the catalyst filled in the reactor 3 by electrochemical deposition are as follows: preparing an aqueous solution or organic solution containing a metal element precursor, and adding an appropriate amount of auxiliary reagents to adjust the pH value to between 3 and 7. Commonly used auxiliary reagents include buffers (such as acetic acid-sodium acetate buffer, citric acid-sodium citrate buffer), chelating agents (such as EDTA, sodium citrate) and surfactants (such as sodium dodecyl sulfate SDS, polyvinyl pyrrolidone PVP), etc.; immersing a substrate material (a sheet, tube, three-dimensional porous material or mesh structure made of one or more metals such as iron, cobalt, nickel, copper, gold, platinum or ruthenium) as a cathode in the above solution and connecting it to a DC regulated power supply; at the same time, using a platinum mesh as an anode, setting the voltage to 10 to 60 volts, and performing an electrodeposition operation for 0.5 to 2 hours in a constant voltage mode; after the deposition is completed, the sample is washed with deionized water and dried, and finally an efficient ammonia decomposition catalyst for ammonia decomposition is obtained. The prepared catalyst has high electrical conductivity, good thermal conductivity and ferromagnetic properties.

[0015] Furthermore, the metal element precursor may be one or more combinations of nitrates, chlorides, sulfates, carbonates, phosphates, methoxides, ethoxides, formates and acetates of metals such as iron, cobalt, nickel, copper, gold, platinum or ruthenium.

[0016] Furthermore, the materials selected for the spacing layer 4 in the electromagnetic induction cold start subsystem include but are not limited to aerogel, glass fiber or quartz wool to reduce heat conduction.

[0017] Furthermore, the high-frequency induction heater 7 in the electromagnetic induction cold start subsystem can adjust the current of the alternating current in the range of 1 to 1000A, with an output power range of 50W to 100kW, ensuring that the reaction temperature is accurately maintained at 500 to 1500 degrees Celsius.

[0018] Furthermore, the heat-insulating layer 13 wrapped around the heat supply chamber 12 in the thermal catalytic decomposition of ammonia subsystem is composed of a heat-insulating material with extremely low thermal conductivity (such as aerogel, glass fiber or quartz wool), forming an annular heat-insulating shell. The heat-insulating layer can significantly reduce heat loss, ensure temperature stability during the reaction process, and improve the energy efficiency of the system.

[0019] Furthermore, the heating chamber 12 in the thermal catalytic decomposition of ammonia subsystem has a multi-mode heating function, including electric heating, hot air heating, and hydrogen combustion heating, etc. Specifically, the electric heating is achieved by winding a resistance wire around the outside of the ammonia decomposition reaction tube 11. When the current passes through the resistance wire, heat is generated, which directly heats the ammonia decomposition reaction tube efficiently; the hot air heating and hydrogen combustion heating are completed by heat exchange between the heating gas input port 14 and the heating gas output port 10, ensuring that a stable heating source can be provided under different operating conditions.

[0020] Furthermore, the monolithic catalyst loaded in the ammonia decomposition reaction tube 11 in the thermal catalytic decomposition ammonia subsystem is a mixed-incorporation catalyst or a coated catalyst, and the carrier material of these catalysts is selected from metal oxide carriers or carbon-based carriers. Among them, the metal oxide carrier includes magnesium oxide, calcium oxide, barium oxide, aluminum oxide, cerium oxide, lanthanum oxide and gadolinium oxide, etc.; the carbon-based carrier includes various forms such as carbon black, carbon nanotubes, graphene, fullerene and activated carbon. The mixed-incorporation catalyst is prepared by uniformly mixing the selected active metal with the carrier material, and drying and sintering the catalyst block with high mechanical strength and good mass transfer characteristics. The coated catalyst is prepared by mixing the active metal with a suitable binder (including organic binders such as polyvinyl alcohol, cellulose derivatives, polyethylene oxide, starch and its derivatives, phenolic resin or urea-formaldehyde resin, and inorganic binders such as silicates, aluminates, phosphates, silica sol, titanate coupling agents or ceramic binders) to form a slurry, which is then ball-milled to obtain a uniform catalyst slurry; the slurry is then applied to a pre-selected monolithic catalyst carrier (such as magnesium oxide, alumina particles, cordierite honeycomb ceramics, etc.) by impregnation or direct coating, and the catalyst layer is subsequently fixed by drying and calcination to ensure its stability and durability under reaction conditions, ultimately producing a monolithic catalyst product. The active metal is one or more combinations of precious metals (such as ruthenium, platinum, iridium, gold, etc.) or non-precious metals (such as cobalt, nickel, iron, molybdenum, etc.). In order to enhance the performance of the active metal main catalyst, a promoter is added, mainly including alkali metals (such as lithium, sodium, potassium, cesium, etc.) and alkaline earth metals (such as magnesium, calcium, barium, etc.) to optimize the catalytic reaction conditions and improve the catalytic efficiency.

[0021] Furthermore, the adsorption column 21 of the power subsystem is a temperature swing adsorption or pressure swing adsorption, which is used to purify and dehydrate the hydrogen to ensure that the hydrogen entering the power generation device 22 meets the purity requirements. The adsorption column 21 is filled with an adsorbent, which can be activated carbon, molecular sieve, metal organic framework, silica gel, etc.

[0022] Furthermore, the power inverter 23 of the power subsystem can convert the direct current output by the power generation device 22 into alternating current. The power inverter 23 can be a Haidier power inverter HBK5-220A, etc., and the power generation device 22 can be a Horizon H-12, etc.

[0023] The multifunctional ammonia decomposition hydrogen production system of the present invention has the following beneficial effects:

[0024] (1) Electromagnetic induction cold start subsystem: By directly heating the efficient ammonia decomposition catalyst in the reactor 3, an alternating magnetic field is used to generate eddy currents and heat inside the catalyst. This method significantly shortens the heat transfer path and makes the heating and cooling response faster; because the heat is directly generated in the catalyst, the system startup speed is accelerated, energy consumption is reduced, and efficiency is improved;

[0025] (2) Thermal catalytic decomposition of ammonia subsystem: The ammonia decomposition reaction tube 11 is filled with an integral high-performance catalyst, so that the ammonia decomposition reaction can be carried out efficiently and stably at a relatively low temperature (below 500° C.); this feature ensures that the system can continuously provide high-quality hydrogen, and enhances the reliability and hydrogen production of the system;

[0026] (3) Power subsystem: By recycling the waste heat generated by the combustion chamber and the electricity generated by the power generation device, multi-level energy utilization is achieved; this design improves the energy utilization efficiency of the entire system, reduces operating costs, and promotes the effective recycling of resources;

[0027] (4) Multi-system synergy: The collaborative work among the various parts of the system solves the cold start problem and high energy consumption problems encountered in the traditional ammonia decomposition hydrogen production process, realizes the effective management and recycling of energy, improves the overall performance of the system, and provides strong support for the development of clean energy vehicles.

[0028] The above improvement measures enable the system to perform excellently in low-temperature startup and efficient operation, and have significant economy and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention, the following will briefly introduce the drawings required for use in the specific embodiments. Obviously, the drawings in the following description only show some embodiments of the present invention.

[0030] Figure 1 It is a schematic diagram of the structure of a multifunctional ammonia decomposition hydrogen production system;

[0031] like Figure 1 As shown, the names of the various parts are: ammonia storage device 1, flow control valve 2, reactor 3, spacer layer 4, induction coil 5, mixed gas outlet 6, high-frequency induction heater 7, temperature sensor 8, mixed gas inlet 9, heating gas output port 10, ammonia decomposition reaction tube 11, heating chamber 12, insulation layer 13, heating gas input port 14, hydrogen and nitrogen mixed gas output port 15, hot gas outlet 16, combustion chamber 17, waste heat recovery pipeline 18, air supply device 19, cold air inlet 20, adsorption column 21, power generation device 22, power inverter 23;

[0032] Figure 2It is a schematic diagram of the structure of the electromagnetic induction cold start subsystem;

[0033] like Figure 2 As shown, the induction coil 5 surrounds the outer side of the spacer layer 4, and the spacer layer 4 wraps the reactor 3 in the center. The induction coil 5 heats the efficient ammonia decomposition catalyst in the reactor 3 through electromagnetic induction;

[0034] Figure 3 The heating and cooling curves of 5wt.% Ni-loaded iron-based catalyst at different currents;

[0035] Figure 4 It is a schematic diagram of the structure of the thermal catalytic decomposition ammonia subsystem;

[0036] like Figure 4 As shown, the ammonia decomposition reaction tube 11 is located in a heating chamber 12, and the outside of the heating chamber 12 is wrapped with a heat-insulating layer 13; the heating chamber 12 is provided with a heating gas outlet 10 and a heating gas inlet 14, and the heating chamber 12 realizes hot air heating and hydrogen combustion heating of the ammonia decomposition reaction tube 11 through heat exchange, and a resistance wire can also be provided in the heating chamber 12 to realize electrical heating of the ammonia decomposition reaction tube 11;

[0037] Figure 5 This is the ammonia conversion curve for thermal catalytic decomposition of ammonia. DETAILED DESCRIPTION

[0038] In order to further illustrate the technical solution and advantages of the present invention, the following will be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are intended to explain the technical details and implementation methods of the present invention rather than to limit its scope. Other implementation methods that can be derived by technicians in the relevant field based on the technical inspiration provided in this article without creative work are also protected by the present invention.

[0039] Example 1

[0040] The catalyst filled in the reactor 3 is prepared by electrochemical deposition. First, 70 mL of 0.1 M nickel nitrate aqueous solution is prepared. 0.05 M citric acid-sodium citrate buffer solution is added to stabilize the pH value at about 4. In addition, a small amount of chelating agent EDTA (0.01 M) is added to control the metal ion concentration and prevent precipitation from forming. A piece of iron sheet with a size of 1 cm × 10 cm is selected as the cathode substrate material. The iron sheet is finely polished and ultrasonically cleaned to remove surface impurities and ensure good conductivity and deposition effect. The treated iron sheet is immersed in the above-prepared electrolyte and connected to a DC regulated power supply. The voltage is set to 20 volts and the electrodeposition operation is performed for 1 hour in constant voltage mode. During this process, nickel ions are gradually deposited on the surface of the iron sheet under the action of the electric field to form a uniform and dense catalytic layer, and finally the surface of the iron sheet contains about 5 wt.% of nickel active components. After the electrodeposition is completed, the iron sheet is taken out and washed with deionized water several times to thoroughly remove the residual electrolyte and other impurities. Subsequently, the sample was dried in an oven at 60 degrees Celsius for 2 hours to ensure that the water was completely evaporated, and finally an efficient ammonia decomposition catalyst for ammonia decomposition, namely, a 5 wt.% Ni-loaded iron-based catalyst, was obtained.

[0041] like Figure 2 As shown, the reactor 3 of the electromagnetic induction cold start subsystem is a quartz tube with an outer diameter of 20 mm, a wall thickness of 2 mm and a tube length of 100 mm. The interior of the reactor 3 is filled with an iron-based catalyst loaded with 5 wt.% Ni for ammonia decomposition reaction; the exterior is wrapped with a 10 mm thick quartz wool as a spacer layer 4 to provide thermal insulation. When the high-frequency induction heater 7 provides currents of 500A, 400A and 300A respectively, the temperature sensor 8 monitors that the surface temperature of the iron-based catalyst can quickly rise to about 700°C, 680°C and 655°C within 1 second. After turning off the high-frequency induction heater 7, the system temperature can drop to about 100°C in about 1 minute (see Figure 3 ). Gas chromatography was used to evaluate the ammonia decomposition effect of the electromagnetic induction cold start subsystem. At a space velocity of 18000 mL / g cat / h, by adjusting the current of the high-frequency induction heater 7 to 500 A, the ammonia decomposition efficiency can reach 32% within 5 seconds after startup, thus meeting the requirement of rapid startup of hydrogen production.

[0042] As a preferred embodiment of the present invention, the steps for preparing the integral catalyst of the thermal catalytic decomposition of ammonia subsystem are as follows: first, the selected Ru-MgO active metal and the PVA organic binder are mixed in a mass ratio of 7:3 to form a slurry; then, the catalyst raw material is placed in a ball mill, and 30 mL of ethanol is added, and ball milling treatment is performed at a speed of 300 rpm for 4 hours to obtain a uniform catalyst slurry; then, the obtained catalyst slurry is uniformly coated on the preselected integral cordierite catalyst carrier; then, the coated integral catalyst carrier is fully dried and calcined at 500°C for 4 hours to finally prepare an integral catalyst product; finally, the prepared integral catalyst product is loaded into the ammonia decomposition reaction tube 11, and the ammonia decomposition effect of the thermal catalytic decomposition of ammonia subsystem is evaluated by gas chromatography. At 18000 mL / g cat The ammonia decomposition performance was evaluated under the conditions of a space velocity of 1.500 °C and a working temperature of 500 °C (see Figure 5 ), and found that the catalyst's ammonia decomposition efficiency remained at around 90% within 120 hours. This process ensures the catalyst's high efficiency and stability, providing ideal conditions for the ammonia decomposition reaction.

[0043] The specific embodiments described in detail in the present invention are only used to explain the technical principles and implementation methods of the present invention, and do not constitute a limitation on the scope of protection of the present invention. It should be understood by those skilled in the art that, without departing from the spirit and principles of the present invention, the various details in the above embodiments can be modified and adjusted. For example, parameters such as reactor size, catalyst composition ratio, ball milling conditions, etc. can be appropriately changed according to the different needs of actual application scenarios. Therefore, all these changes should be regarded as falling within the scope of protection of the present invention.

Claims

1. A multifunctional ammonia decomposition hydrogen production system, characterized in that: The ammonia decomposition hydrogen production system is composed of an electromagnetic induction cold start subsystem, a thermal catalytic decomposition ammonia subsystem and a power subsystem; wherein the electromagnetic induction cold start subsystem is composed of an ammonia storage device (1), a flow control valve (2), a reactor (3) with a mixed gas outlet (6), a spacer layer (4), an induction coil (5), a high-frequency induction heater (7) and a temperature sensor (8); the thermal catalytic decomposition ammonia subsystem is composed of an ammonia decomposition reaction tube (11) placed in a heating chamber (12), and the outside of the heating chamber (12) is wrapped with a thermal insulation layer (13). ), the heating chamber (12) is provided with a heating gas output port (10) and a heating gas input port (14), the ammonia decomposition reaction tube (11) is provided with a mixed gas inlet (9) and a hydrogen-nitrogen mixed gas outlet (15); the power subsystem is composed of a combustion chamber (17), an air supply device (19), an adsorption column (21), a power generation device (22) and an electric power inverter (23), the outside of the combustion chamber (17) is wrapped with a waste heat recovery pipeline (18), and the waste heat recovery pipeline (18) is provided with a hot gas outlet (16) and a cold gas inlet (20); In the electromagnetic induction cold start subsystem, an ammonia storage device (1) is used to store and provide ammonia, and a flow control valve (2) is installed on the pipeline between the ammonia storage device (1) and the reactor (3); the reactor (3) is a tubular structure made of non-electromagnetic induction materials, and is filled with a high-efficiency ammonia decomposition catalyst. The hydrogen generated after decomposition and the mixture of incompletely decomposed ammonia are discharged through the mixed gas outlet (6) and enter the thermal catalytic decomposition ammonia subsystem; the induction coil (5) is spirally wound on the outer surface of the spacer layer (4), and the high-frequency induction heater (7) is connected to the induction coil (5). The high-frequency induction heater (7) controls the current of the alternating current, generates an alternating magnetic field through the induction coil (5), and heats the catalyst in the reactor (3), ensuring that the temperature of the reactor (3) quickly rises to 500-1500°C to promote the ammonia decomposition reaction; the high-frequency induction heater (7) is connected to the temperature sensor (8), and the temperature sensor (8) is placed at the rear end of the reactor (3); In the thermal catalytic decomposition of ammonia subsystem, the mixed gas outlet (6) of the electromagnetic induction cold start subsystem is directly connected to the mixed gas inlet (9) of the ammonia decomposition reaction tube (11); the heating chamber (12) tightly surrounds the ammonia decomposition reaction tube (11) and provides multiple heating modes such as electric heating, hot air heating and hydrogen combustion heating to heat the temperature of the ammonia decomposition reaction tube (11) to 400-600° C.; the heating chamber (12) is equipped with a heating gas outlet (10) and a heating gas inlet (14) for the hot air heating and hydrogen combustion heating modes; the ammonia decomposition reaction tube (11) is equipped with an integral catalyst to promote thermal catalytic decomposition of ammonia, and the generated hydrogen and nitrogen mixed gas is then guided into the power subsystem through the hydrogen and nitrogen mixed gas outlet (15); The mixed gas outputted from the hydrogen-nitrogen mixed gas output port (15) of the ammonia decomposition reaction tube (11) enters the power subsystem and is divided into two parallel branches. The first branch is connected to a combustion chamber (17) and an air supply device (19). The combustion chamber (17) is wrapped with a waste heat recovery pipeline (18). The two ends of the waste heat recovery pipeline (18) are respectively provided with a hot gas outlet (16) and a cold gas inlet (20). The hot gas outlet (16) is connected to the heating gas input port (14) through a pipeline, and is used for heat compensation of the thermal catalytic decomposition ammonia subsystem; the cold gas inlet (20) is connected to the heating gas output port (10) through a pipeline; the air supply device (19) is simultaneously connected to the cold gas inlet (20) and the combustion chamber (17) inlet, on the one hand, providing sufficient oxygen supply for the combustion of the mixed gas in the combustion chamber (17), thereby supporting the smooth progress of the combustion process; on the other hand, the air supply device (19) 9) The gas provided enters the waste heat recovery pipeline (18) through the cold air inlet (20), and the heat generated by the combustion of the mixed gas in the combustion chamber (17) can heat the gas in the waste heat recovery pipeline (18) to a higher temperature. Then, the hot air is transmitted from the hot air outlet (16) through the pipeline to the heating gas input port (14) and enters the heating chamber (12), and the required heat compensation is provided for the thermal catalytic decomposition of ammonia through heat exchange; the cold air after heat exchange is transmitted from the heating gas output port (100) through the pipeline to the cold air inlet (20) and flows back to the waste heat recovery pipeline (18) for circulation; the second branch is connected in sequence with an adsorption column (21), a power generation device (22) and an electric inverter (23), and the output end of the electric inverter (23) is connected to the heating chamber (12) and the induction coil (5), so as to provide alternating current for the electric heating of the heating chamber (12) and the electromagnetic induction heating of the induction coil (5).

2. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The reactor (3) is made of quartz, ceramic or corundum and has a cylindrical structure with an outer diameter of 10 to 100 mm, a wall thickness of 2 to 5 mm and a length of 100 to 500 mm.

3. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The high-efficiency ammonia decomposition catalyst filled in the reactor (3) is a metal oxide catalyst, a metal-based material catalyst or a carbon-based material catalyst supported by one or more metals; the one or more metals are iron, cobalt, nickel, copper, gold, platinum or ruthenium, the metal oxide is magnesium oxide, calcium oxide, barium oxide, aluminum oxide, cerium oxide, lanthanum oxide, gadolinium oxide, titanium oxide or zirconium oxide, the metal-based material is one or two of iron, cobalt, nickel, manganese or copper, and the carbon-based material is graphite carbon, carbon nanotubes, graphene or graphene oxide.

4. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The high-efficiency ammonia decomposition catalyst filled in the reactor (3) is in the form of powder, granules, columns, tubes, nets or sheets; it is obtained by loading one or more metal element precursors on metal oxides, metal-based materials or carbon-based materials through impregnation, electrochemical deposition, alkali precipitation, Joule heat in-situ synthesis, hydrothermal, chemical vapor deposition or physical vapor deposition, wherein the metal element precursor is one or more combinations of nitrates, chlorides, sulfates, carbonates, phosphates, methoxides, ethoxides, formates or acetates of iron, cobalt, nickel, copper, gold, platinum or ruthenium.

5. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The material selected for the spacing layer (4) in the electromagnetic induction cold start subsystem is aerogel, glass fiber or quartz wool to reduce heat conduction.

6. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The high-frequency induction heater (7) in the electromagnetic induction cold start subsystem can adjust the current of the alternating current to a range of 1 to 1000A, and the output power range is 50W to 100kW.

7. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The heat-insulating layer (13) wrapped outside the heating chamber (12) in the thermal catalytic decomposition ammonia subsystem is composed of aerogel, glass fiber or quartz wool heat-insulating materials with extremely low thermal conductivity, forming an annular heat-insulating shell.

8. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The electric heating of the heating chamber (12) in the thermal catalytic decomposition of ammonia subsystem is achieved by winding a resistance wire around the outside of the ammonia decomposition reaction tube (11). When current passes through the resistance wire, heat is generated to directly heat the ammonia decomposition reaction tube efficiently.

9. A multifunctional ammonia decomposition hydrogen production system as claimed in claim 1, characterized in that: The integral catalyst loaded in the ammonia decomposition reaction tube (11) in the thermal catalytic decomposition of ammonia subsystem is a mixed-incorporation type catalyst or a coated-type catalyst. The mixed-incorporation type catalyst is prepared by uniformly mixing the selected active metal with the carrier material, and then drying and sintering the mixture; while the coated-type catalyst is prepared by mixing the active metal with a suitable binder to form a slurry, applying the slurry to a pre-selected carrier material by an impregnation method or a direct coating method, and then fixing the catalyst layer by drying and calcining.

10. The multifunctional ammonia decomposition hydrogen production system according to claim 1, characterized in that: The adsorption column (21) of the power subsystem is a temperature swing adsorption or a pressure swing adsorption, and the adsorption column (21) is filled with an adsorbent, which is activated carbon, molecular sieve, metal organic framework or silica gel.

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