Quick starting system for hydrogen production through ammonia decomposition

Abstract

The utility model discloses an ammonia decomposition hydrogen production quick start system which comprises a liquid ammonia source, a gasifier, a first heat exchanger, an ammonia decomposition reactor, a plasma ammonia decomposition hydrogen production reactor, a membrane separation purifier, a combustor and a pure hydrogen collector. The system preheats ammonia gas through a first heat exchanger, an ammonia gas channel outlet of the first heat exchanger is divided into two paths, one path is communicated with an ammonia gas channel of an ammonia decomposition reactor for ammonia decomposition, and decomposed high-temperature product mixed gas serves as a heat source of the first heat exchanger; the other path is communicated with the plasma ammonia decomposition hydrogen production reactor and is used for quickly decomposing ammonia gas and providing a hydrogen source for quickly igniting the combustor; and the combustor provides heat energy for ammonia decomposition in the ammonia decomposition reactor. According to the utility model, the plasma ammonia decomposition hydrogen production reactor is introduced, and hydrogen is generated in an extremely short time by utilizing a plasma catalysis process and is used for combustion of the combustor, so that the ammonia decomposition reactor is rapidly heated, and the starting time of the whole system is obviously shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen energy, in particular to a quick start system for hydrogen production by decomposing ammonia. Background Art

[0002] Because traditional ammonia decomposition hydrogen production systems require a high temperature environment for the ammonia decomposition reaction, the process from cold start to stable hydrogen supply typically takes a long time (over 30 minutes). This process not only affects the system's response speed and flexibility, but also increases energy consumption and production costs. In situations where emergency hydrogen supply or rapid startup are required, the long startup time of traditional systems becomes a significant bottleneck.

[0003] An important future application scenario for ammonia-to-hydrogen systems is as mobile, independent energy systems. Under independent energy supply conditions, the main reason for the slow startup time of ammonia decomposition hydrogen production systems is the time required to reach high-temperature reaction conditions. If a backup power source such as a lithium battery is used for heating, it is difficult to achieve short-term heating due to limitations in heating power and equipment complexity. Therefore, rapidly heating the system through fuel combustion is a solution. However, under independent energy supply conditions, obtaining large quantities of fuel with high calorific value is another technical issue. Therefore, how to solve the problem of rapid startup of ammonia decomposition hydrogen production systems has become an important demand and research direction in this field. Utility Model Content

[0004] In response to the shortcomings of the existing technology, the utility model provides a rapid start-up system for hydrogen production by ammonia decomposition. By introducing a plasma ammonia decomposition hydrogen production reactor, the plasma catalytic process is used to generate hydrogen in an extremely short time, and hydrogen is used for combustion in the burner, thereby quickly heating the ammonia decomposition reactor and significantly shortening the startup time of the entire system.

[0005] The utility model adopts the following technical solutions:

[0006] A rapid start-up system for hydrogen production from ammonia decomposition, comprising a liquid ammonia source, a vaporizer, a first heat exchanger, an ammonia decomposition reactor, a plasma ammonia decomposition hydrogen production reactor, a membrane separation purifier, a burner and a pure hydrogen collector; the liquid ammonia source is connected to the vaporizer for gasifying liquid ammonia into ammonia; the first heat exchanger comprises a first heat exchange ammonia channel and a first heat exchange product gas channel, the ammonia decomposition reactor comprises an ammonia decomposition reaction ammonia channel and an ammonia decomposition reaction flue gas channel, the membrane separation purifier comprises a purified hydrogen channel and an unpurified hydrogen channel, the outlet of the vaporizer is connected to the inlet of the first heat exchange ammonia channel, the outlet of the first heat exchange ammonia channel is divided into two paths, one path is connected to the inlet of the ammonia decomposition reaction ammonia channel, and the ammonia after heat exchange in the first heat exchanger is passed into the ammonia decomposition reactor for ammonia decomposition, and the other path is connected to the inlet of the plasma ammonia decomposition hydrogen production reactor. The outlet of the ammonia channel of the ammonia decomposition reaction is connected to the inlet of the first heat exchange product gas channel, and the outlet of the first heat exchange product gas channel is connected to the inlet of the unpurified hydrogen channel. The product mixed gas after decomposition by the ammonia decomposition reactor is used as the heat exchange medium of the first heat exchanger to exchange heat with the ammonia passing through the first heat exchange ammonia channel, and then enters the membrane separation purifier for hydrogen purification; the purified hydrogen enters the purified hydrogen channel, and the outlet of the purified hydrogen channel is connected to the inlet of the pure hydrogen collector to cool, collect and store the purified hydrogen; the outlet of the plasma ammonia decomposition hydrogen production reactor is connected to the burner to provide a hydrogen source for rapid ignition of the burner; the outlet of the burner is connected to the inlet of the ammonia decomposition reaction flue gas channel to provide heat energy for the decomposition of ammonia in the ammonia decomposition reactor.

[0007] The system also includes a second heat exchanger and an air compressor. The second heat exchanger includes a second heat exchange air channel and a second heat exchange flue gas channel. The outlet of the burner is connected to the inlet of the ammonia decomposition reaction flue gas channel to provide heat energy for the decomposition of ammonia in the ammonia decomposition reactor. The outlet of the air compressor is connected to the inlet of the second heat exchange air channel. The outlet of the ammonia decomposition reaction flue gas channel is connected to the inlet of the second heat exchange flue gas channel to preheat the air entering the second heat exchange air channel through the air compressor. The outlet of the second heat exchange flue gas channel is connected to the flue gas treatment and release unit to treat and release the flue gas after combustion and heat exchange.

[0008] The system also includes a gas mixer. The outlet of the second heat exchange flue gas channel, the outlet of the unpurified hydrogen channel, the outlet of the pure hydrogen collector, and the outlet of the plasma ammonia decomposition hydrogen production reactor are respectively connected to the inlet of the gas mixer. The hot air after heat exchange through the second heat exchanger, the unpurified hydrogen through the unpurified hydrogen channel, the pure hydrogen collected in the pure hydrogen collector, and the hydrogen decomposed by the plasma ammonia decomposition hydrogen production reactor enter the gas mixer. After the gases are mixed in the gas mixer, the mixed gas flowing out flows into the burner and is ignited and burned in the burner to produce high-temperature flue gas.

[0009] The separation membrane used for purification in the membrane separation purifier is a selective hydrogen permeable membrane, which can efficiently separate hydrogen from other gases. After the gas flows out from the outlet of the product gas channel of the first heat exchanger, it enters the unpurified hydrogen channel of the purifier. Thereafter, the gas will be split into two directions. The hydrogen that passes through the selective hydrogen permeable membrane enters the purified hydrogen channel, while the unpurified gas that does not pass through the selective hydrogen permeable membrane, containing hydrogen, nitrogen and a small amount of unreacted ammonia, enters the gas mixer.

[0010] Preferably, the separation membrane in the membrane separation purifier is a metal vanadium or metal niobium alloy membrane, and the alloy material is represented by M1. x M2 y M3 z , where M1 represents one or two of metals V and Nb, M2 represents one or more of metals W, Mo, and Ta, and M1 and M2 form a solid solution. M3 is a deoxidizing alloying element and represents one of Cr, Mn, Ti, Al, Y, Ma, La, Sr, Ba, and Ce. The subscripts x, y, and z represent the molar fractions of the element atoms of M1, M2, and M3, respectively, where x is 0.87 to 0.96, y is 0.03 to 0.13, and z is 0.005 to 0.01, and x+y+z=1.00.

[0011] Preferably, the operating temperature of the separation membrane is 240-640° C., and the pressure of the gas entering the membrane separation purifier is >0.2 MPa.

[0012] More preferably, the operating temperature of the separation membrane is 300-400° C., and the pressure of the gas entering the membrane separation purifier is 0.4-1.2 MPa.

[0013] Preferably, the ammonia decomposition reactor is a fixed-bed reactor, and an ammonia decomposition catalyst is filled in the ammonia channel of the ammonia decomposition reactor. After the reactant ammonia gas flow flows out of the first heat exchanger, it enters the ammonia channel of the ammonia decomposition reactor and flows through the ammonia decomposition catalyst to be converted into decomposition products to obtain hydrogen and nitrogen. The plasma ammonia decomposition hydrogen production reactor includes a plasma reactor ammonia channel and a plasma generator. The plasma ammonia decomposition hydrogen production reactor is a fixed-bed reactor, and the ammonia decomposition catalyst is filled in the plasma reactor ammonia channel. The plasma generator is installed on the outer wall of the plasma reactor ammonia channel, and the plasma generator adopts a dielectric barrier discharge technology route. After the reactant ammonia gas flow flows out of the first heat exchanger, except for a portion entering the ammonia channel of the ammonia decomposition reactor, the other portion enters the plasma reactor ammonia channel of the plasma ammonia decomposition hydrogen production reactor, and the ratio of the former flow rate to the latter flow rate is in the range of 5-40 times.

[0014] Preferably, the ammonia decomposition catalyst filled in the ammonia decomposition reactor is one or a mixture of an iron-based catalyst and a ruthenium-based catalyst; after the device is running smoothly, the reaction conditions of the ammonia decomposition reactor are as follows: the operating temperature is 340-840°C, the gas pressure in the reactor is controlled at 0.2-3 MPa, and the ammonia gas space velocity is 100-10000h -1 .

[0015] More preferably, the reaction conditions of the ammonia decomposition reactor are as follows: the operating temperature is 440-580°C, the gas pressure in the reactor is controlled at 0.5-1.5 MPa, and the ammonia gas space velocity is 1400-6000 h -1 .

[0016] Preferably, the ammonia decomposition catalyst filled in the ammonia channel of the plasma reactor is a supported ruthenium-based catalyst, wherein the active metal component is ruthenium, and the catalyst carrier is lanthanum oxide, cerium oxide, yttrium oxide, zirconium oxide, titanium oxide or a mixture of the above components in any proportion; in the ammonia channel of the plasma reactor, the ammonia gas space velocity is 100 to 10000 h -1 .

[0017] More preferably, the ammonia gas space velocity in the ammonia channel of the plasma reactor is 400 to 6000 h -1 .

[0018] The burner contains an ignition device. Under appropriate fuel flow rate and air flow rate, after successful ignition and stable operation of the device, the air flow rate is 4 to 30 times the ammonia flow rate flowing into the ammonia decomposition reactor; whether the fuel combustion state is normal is judged by whether the burner outlet temperature is not less than 640°C.

[0019] The purity of the purified hydrogen flowing out of the membrane separation purifier is not less than 99.99%.

[0020] The technical solution of this utility model has the following advantages:

[0021] A. The utility model introduces a plasma ammonia decomposition hydrogen production reactor and utilizes the plasma catalytic process to generate hydrogen in a very short time (within 5 minutes). The hydrogen is then used for combustion in the burner, thereby rapidly heating the ammonia decomposition reactor and significantly shortening the startup time of the entire system to about 10 minutes.

[0022] B. The plasma catalytic process of this utility model is characterized by high efficiency and low temperature, which can reduce startup energy consumption while improving the overall energy efficiency of the system. In addition, the rapid startup capability enables the system to respond more quickly to changes in hydrogen demand, improving system flexibility and reliability.

[0023] C. The quick start system of this utility model integrates multiple advanced technologies such as plasma catalysis, heat exchange, membrane separation and purification, forming an efficient, energy-saving and flexible ammonia decomposition and hydrogen production solution.

[0024] D. In terms of temperature and pressure compatibility, the preferred operating temperature of the metal separation membrane of the present invention is 300-400°C, and the temperature within the reactor is preferably 440-580°C. This indicates that the temperature and pressure range of the product gas after passing through the first heat exchanger is well matched to the operating temperature range of the metal separation membrane. In particular, the preferred reaction temperature and pressure ranges are well matched to the temperature and pressure ranges where the alloy membrane achieves excellent separation performance. This eliminates the need for further process changes such as heating and pressurizing the product gas during gas separation and purification using the alloy membrane, simplifying the process and saving overall energy consumption.

[0025] E. This utility model fully utilizes the operating temperature and pressure characteristics of the ammonia decomposition hydrogen production reaction, making it suitable for hydrogen purification using non-precious metal alloy membranes. The use of non-precious metal alloy membranes significantly reduces the cost of separation membranes compared to palladium-based membranes. Furthermore, compared to commonly used pressure swing adsorption separation methods, the alloy membranes in this utility model significantly reduce weight and volume for equivalent hydrogen separation flux, which is of great significance for the miniaturization, modularization, and portability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention, the following will briefly introduce the drawings required for use in the specific implementation methods. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the overall structure of the ammonia decomposition hydrogen production quick start system.

[0028] The following are marked in the figure:

[0029] 1-Liquid ammonia source; 2-Gasifier; 3-First heat exchanger, 31-First heat exchange ammonia channel, 32-First heat exchange product gas channel; 4-Ammonia decomposition reactor, 41-Ammonia decomposition reaction ammonia channel, 42-Ammonia decomposition reaction flue gas channel; 5-Plasma ammonia decomposition hydrogen production reactor, 51-Plasma reactor ammonia channel, 52-Plasma generator; 6-Second heat exchanger, 61-Second heat exchange air channel, 62-Second heat exchange flue gas channel; 7-Membrane separation purifier, 71-Unpurified hydrogen channel, 72-Purified hydrogen channel; 8-Gas mixer; 9-Burner; 10-Pure hydrogen collector; 20-Air compressor; 30-Flue gas treatment and release unit. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] like Figure 1As shown, this embodiment provides a rapid start-up system for hydrogen production by ammonia decomposition, comprising a liquid ammonia source 1, a vaporizer 2, a first heat exchanger 3, an ammonia decomposition reactor 4, a plasma ammonia decomposition hydrogen production reactor 5, a membrane separation purifier 7, a burner 9, and a pure hydrogen collector 10. The liquid ammonia source 1 is connected to the vaporizer 2 and is used to gasify the liquid ammonia into ammonia gas. The first heat exchanger 3 includes a first heat exchange ammonia gas channel 31 and a first heat exchange product gas channel 32; the ammonia decomposition reactor 4 includes an ammonia decomposition reaction ammonia gas channel 41 and an ammonia decomposition reaction flue gas channel 42; the plasma ammonia decomposition hydrogen production reactor 5 includes a plasma reactor ammonia gas channel 51 and a plasma generator 52; and the membrane separation purifier 7 includes an unpurified hydrogen gas channel 71 and a purified hydrogen gas channel 72. The outlet of vaporizer 2 is connected to the inlet of first heat exchange ammonia channel 31. The outlet of first heat exchange ammonia channel 31 is divided into two channels: one channel is connected to the inlet of ammonia decomposition reaction ammonia channel 41, passing ammonia after heat exchange in first heat exchanger 3 into ammonia decomposition reactor 4 for ammonia decomposition; the other channel is connected to the inlet of plasma reactor ammonia channel 51 of plasma ammonia decomposition hydrogen production reactor 5 for rapid ammonia decomposition. The outlet of ammonia decomposition reaction ammonia channel 41 is connected to the inlet of first heat exchange product gas channel 32, which in turn is connected to the inlet of unpurified hydrogen channel 71. The product gas mixture after decomposition in ammonia decomposition reactor 4 serves as the heat exchange medium in first heat exchanger 3, exchanges heat with ammonia passing through first heat exchange ammonia channel 31, and then passes into membrane separation purifier 7 for hydrogen purification. The purified hydrogen enters purified hydrogen channel 72, the outlet of which is connected to the inlet of pure hydrogen collector 10 for cooling, collection, and storage. The outlet of the plasma reactor ammonia channel 51 of the plasma ammonia decomposition hydrogen production reactor 5 is connected to the burner 9, providing a hydrogen source for the rapid ignition of the burner 9; the outlet of the burner 9 is connected to the inlet of the ammonia decomposition reaction flue gas channel 42, providing heat energy for the decomposition of ammonia in the ammonia decomposition reactor 4.

[0032] Furthermore, the system also includes a second heat exchanger 6 and an air compressor 20. The second heat exchanger 6 includes a second heat exchange air channel 61 and a second heat exchange flue gas channel 62. The outlet of the burner 9 is connected to the inlet of the ammonia decomposition reaction flue gas channel 42, providing heat energy for the decomposition of ammonia in the ammonia decomposition reactor 4. The outlet of the air compressor 20 is connected to the inlet of the second heat exchange air channel 61, and the outlet of the ammonia decomposition reaction flue gas channel 42 is connected to the inlet of the second heat exchange flue gas channel 62, for preheating the air entering the second heat exchange air channel 61 through the air compressor 20. The outlet of the second heat exchange flue gas channel 62 is connected to the flue gas treatment and release unit 30, for treating and releasing the flue gas after combustion and heat exchange.

[0033] The system also includes a gas mixer 8. The outlet of the second heat exchange flue gas channel 62, the mixed gas outlet of the unpurified hydrogen channel 71, the outlet of the pure hydrogen collector 10, and the gas outlet of the plasma ammonia decomposition hydrogen production reactor 5 are respectively connected to the inlet of the gas mixer 8. The hot air after heat exchange through the second heat exchanger 6, the unpurified hydrogen through the unpurified hydrogen channel 71, the pure hydrogen collected in the pure hydrogen collector 10, and the hydrogen decomposed by the plasma ammonia decomposition hydrogen production reactor 5 enter the gas mixer 8. After the gases are mixed in the gas mixer 8, the mixed gas flowing out flows into the burner 9 and is ignited and burned in the burner 9 to produce high-temperature flue gas.

[0034] The purification membrane in membrane separation purifier 7 is a selective hydrogen-permeable membrane, capable of efficiently separating hydrogen from other gases. After exiting the outlet of product gas channel 32 of first heat exchanger 3, the gas enters unpurified hydrogen channel 71 of purifier 7. Thereafter, the gas is split in two directions: hydrogen that has passed through the separation membrane enters purified hydrogen channel 72, while unpurified gas that has not passed through the separation membrane, containing hydrogen, nitrogen, and a small amount of unreacted ammonia, enters gas mixer 8.

[0035] Specifically, the separation membrane of the membrane separation purifier 7 is made of metal vanadium or metal niobium alloy membrane, and the alloy material can be expressed as: M1 x M2 y M3 z ; Wherein M1 represents metal V or Nb, or both, M2 represents one or more of metals W, Mo, Ta, and M3 represents one of Cr, Mn, Ti, Al, Y, Ma, La, Sr, Ba, and Ce; subscripts x, y, and z represent the molar fractions of the atoms of M1, M2, and M3, respectively, where x is 0.87 to 0.96, y is 0.03 to 0.13, and z is 0.005 to 0.01, and x+y+z=1.00; the two metals M1 and M2 form a solid solution, and M3 acts as a deoxidizing alloying element. In this embodiment, the separation membrane in the membrane separation purifier 7 adopts a metal vanadium-niobium alloy membrane, and the specific material can be expressed as V 0.80 Nb 0.12 Mo 0.05 Cr 0.03 The operating temperature of the separation membrane is 240-640°C, preferably 300-400°C; the operating pressure, i.e., the pressure of the gas entering the membrane separator, is >0.2 MPa, preferably 0.4-1.2 MPa. It is worth noting that if the separation process parameters are outside the above operating temperature and pressure, it does not mean that the hydrogen separation and purification will be completely ineffective, but may lead to one or more of the following situations: reduced purification efficiency, reduced hydrogen purity, and rapid damage to the separation membrane.

[0036] The ammonia decomposition reactor 4 uses a fixed bed reactor, and the ammonia decomposition catalyst is filled in the ammonia channel 41 of the reactor. The reactant ammonia gas flow flows out of the first heat exchanger 3 and enters the ammonia channel 41 of the reactor, and flows through the ammonia decomposition catalyst to be converted into decomposition products to obtain hydrogen and nitrogen. In the ammonia decomposition reactor 4, when the device is running smoothly, the process conditions adopted are as follows: the ammonia decomposition catalyst is an iron-based catalyst, a ruthenium-based catalyst, or a mixture of the two types of catalysts; after the device is running smoothly, the reaction conditions of the reactor are as follows: the operating temperature is 340-840℃, preferably 440-580℃; the gas pressure in the reactor is controlled at 0.2-3MPa, preferably 0.5-1.5MPa; the ammonia gas space velocity is 100-10000h -1 , preferably 1400~6000h -1 .

[0037] The purity of the purified hydrogen flowing out of the membrane separation purifier 7 is not less than 99.99%; the hydrogen yield calculated based on this portion of hydrogen can reach 60-86%.

[0038] The plasma ammonia decomposition hydrogen production reactor 5 uses a fixed-bed reactor, and the reactor ammonia channel 51 is filled with an ammonia decomposition catalyst. A plasma generator 52 is installed on the outer wall of the ammonia channel 51, using dielectric barrier discharge technology. The power supply for the plasma generator is generally a battery, and the specific power supply selection is not limited in this case. After the reactant ammonia gas flow flows out of the first heat exchanger 3, a portion enters the ammonia channel 41 of the ammonia decomposition reactor 4, and the other portion enters the ammonia channel 51 of the plasma ammonia decomposition hydrogen production reactor 5. The ratio of the flow rate of the former to the flow rate of the latter is in the range of 5-40 times. The catalyst filled in the ammonia channel 51 is a supported ruthenium-based catalyst, wherein the active metal component is ruthenium and the catalyst support is lanthanum oxide, cerium oxide, yttrium oxide, zirconium oxide, titanium oxide, or a mixture of the above components in any proportion. The ammonia gas space velocity in the ammonia channel 51 is 100-10,000 h-1 -1 , preferably 1400~6000h -1 .

[0039] This utility model utilizes a plasma ammonia decomposition hydrogen production reactor, utilizing plasma to heat the material and assist in catalysis. The catalytic process generates hydrogen in a very short time (less than 5 minutes), which is then supplied to burner 8 as a heat source during the initial startup phase of the entire system. The rapid supply of hydrogen as fuel accelerates the heat supply required to heat up the ammonia decomposition reactor, enabling it to reach stable operating conditions more quickly, significantly shortening the startup time of the entire system to approximately 10 minutes (calculated from a cold start at room temperature).

[0040] When the corresponding stable process conditions are reached in the ammonia decomposition reactor 4, the ammonia gas flow in the ammonia channel 51 of the plasma ammonia decomposition hydrogen production reactor 5 can be closed, and the power supply of the plasma generator 52 can be cut off. The entire ammonia decomposition system can still maintain stable hydrogen production and output.

[0041] In terms of temperature and pressure compatibility, the preferred operating temperature of the metal separation membrane of the present invention is 300-400°C, and the temperature within the reactor is preferably 440-580°C. This indicates that the temperature and pressure range of the product gas after passing through the first heat exchanger are well matched to the operating temperature range of the metal separation membrane. In particular, the preferred reaction temperature and pressure ranges are well matched to the temperature and pressure ranges where the alloy membrane achieves excellent separation performance. This eliminates the need for further process changes such as heating and pressurizing the product gas during gas separation and purification using the alloy membrane, simplifying the process and saving overall energy consumption.

[0042] Advantages of using non-precious metal membrane separators:

[0043] It's common knowledge in this field that hydrogen purity significantly impacts the quality and value of the resulting hydrogen product. For example, one of the hydrogen purity requirements for low-temperature hydrogen-oxygen fuel cells is a purity of at least 99.99%. Therefore, hydrogen produced through chemical reactions typically requires a purification process to significantly increase the value of the hydrogen product. Commonly used hydrogen purification methods include metal membrane separation and pressure swing adsorption (PSA) based on pressure swing adsorption technology.

[0044] The PSA method utilizes the varying adsorption capacities of porous materials, such as molecular sieves, for different gas molecules, as well as the varying adsorption and desorption capacities and rates under varying pressures. Through multiple pressure swings, some molecules (usually impurities) in the feed gas are adsorbed by the porous material, while more target gas molecules are desorbed, thereby purifying the target gas. While pressure swing adsorption technology is mature, and gases can be purified to high purity levels based on purity requirements, its drawback is that the devices are too large and heavy, making them unsuitable for factory installations and difficult to apply to mobile, skid-mounted, or modular equipment.

[0045] Metal membrane separation utilizes the sieving effect of the metal lattice at a certain temperature on substances of different sizes and their varying chemical affinities, allowing target gas molecules to pass through the membrane more quickly while impurity molecules are unable to, or only slowly, penetrate. Its advantages include high separation efficiency per unit mass, strong chemical selectivity, and ease of miniaturization and lightweighting. However, its main drawbacks are the limited selection of materials and high cost. Palladium membranes, the most widely used metal, are particularly expensive due to their precious metal properties and high processing costs.

[0046] This utility model fully utilizes the operating temperature and pressure characteristics of the ammonia decomposition hydrogen production reaction, making it suitable for hydrogen purification using non-precious metal alloy membranes. The use of non-precious metal alloy membranes significantly reduces the cost of separation membranes compared to palladium-based membranes. Furthermore, compared to commonly used pressure swing adsorption separation methods, the alloy membranes in this utility model significantly reduce weight and volume for equivalent hydrogen separation flux, which is of great significance for the miniaturization, modularization, and portability of the device.

[0047] The fixed-bed reactor described above is a common type of reactor used by those skilled in the art or chemical industry. Its key feature is that the catalyst is packed within the reactor, and the feed gas, under a specific temperature, pressure, and flow rate, passes through the catalyst bed to form reaction products. In this case, ammonia gas flowing from the first heat exchanger enters the reactor and passes through the catalyst to form nitrogen and hydrogen products.

[0048] Due to the thermal effect of the reaction in the fixed bed reactor and the uneven heating of the heat source, the catalyst bed temperature in the reactor, usually called the reaction temperature, is often not uniform at different spatial points, usually within a temperature range. Typically, the temperature difference at different points can be in the range of 10 to 40°C.

[0049] “Gas space velocity” is a commonly used technical term in fixed bed reactor technology. It refers to the volume of gas flowing through a unit volume of catalyst per unit time under standard conditions. Its unit is usually h -1 .

[0050] Physical quantities such as reaction conversion rate, yield, gas purity, and the like are calculated using measurement and calculation methods recognized in the field.

[0051] The fuel cell described herein refers to a hydrogen-oxygen fuel cell, preferably one in which the negative electrode fuel is high-purity hydrogen and the positive electrode uses air as the oxygen source. Those skilled in the art will be aware that hydrogen-oxygen fuel cells require a high purity of hydrogen, which must be no less than 99.99% (v / v).

[0052] In summary, the utility model solves the problems of long startup time, high energy consumption, and poor system flexibility of traditional ammonia decomposition hydrogen production systems through technological innovation, and provides new ideas and methods for the development of the field of ammonia decomposition hydrogen production.

[0053] Any matters not described in this utility model are applicable to the prior art.

[0054] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A quick start system for hydrogen production by decomposing ammonia, characterized in that: The invention comprises a liquid ammonia source (1), a vaporizer (2), a first heat exchanger (3), an ammonia decomposition reactor (4), a plasma ammonia decomposition hydrogen production reactor (5), a membrane separation purifier (7), a burner (9) and a pure hydrogen collector (10); the liquid ammonia source (1) is connected to the vaporizer (2) and is used to gasify the liquid ammonia into ammonia gas; the first heat exchanger (3) comprises a first heat exchange ammonia gas channel (31) and a first heat exchange product gas channel (32); the ammonia decomposition reactor (4) comprises an ammonia decomposition reaction ammonia gas channel (41) and an ammonia decomposition product gas channel (42); The membrane separation purifier (7) includes an unpurified hydrogen channel (71) and a purified hydrogen channel (72). The outlet of the gasifier (2) is connected to the inlet of the first heat exchange ammonia channel (31). The outlet of the first heat exchange ammonia channel (31) is divided into two paths, one of which is connected to the inlet of the ammonia decomposition reaction ammonia channel (41) to pass the ammonia after heat exchange in the first heat exchanger (3) into the ammonia decomposition reactor (4) for ammonia decomposition, and the other is connected to the plasma ammonia decomposition hydrogen production reactor (4) to pass the ammonia after heat exchange in the first heat exchanger (3) into the ammonia decomposition reactor (4) for ammonia decomposition. The inlet of the ammonia decomposition reactor (5) is connected for rapid decomposition of ammonia; the outlet of the ammonia decomposition reaction ammonia channel (41) is connected to the inlet of the first heat exchange product gas channel (32), and the outlet of the first heat exchange product gas channel (32) is connected to the inlet of the unpurified hydrogen channel (71); the product mixed gas after decomposition by the ammonia decomposition reactor (4) is used as the heat exchange medium of the first heat exchanger (3) and is heat exchanged with the ammonia passing through the first heat exchange ammonia channel (31) and then passed into the membrane separation purifier (7) for hydrogen purification The purified hydrogen enters the purified hydrogen channel (72), and the outlet of the purified hydrogen channel (72) is connected to the inlet of the pure hydrogen collector (10) to cool, collect and store the purified hydrogen; the outlet of the plasma ammonia decomposition hydrogen production reactor (5) is connected to the burner (9) to provide a hydrogen source for the rapid ignition of the burner (9); the outlet of the burner (9) is connected to the inlet of the ammonia decomposition reaction flue gas channel (42) to provide heat energy for the decomposition of ammonia in the ammonia decomposition reactor (4).

2. The ammonia decomposition hydrogen production rapid start-up system according to claim 1, characterized in that: The system further comprises a second heat exchanger (6) and an air compressor (20), wherein the second heat exchanger (6) comprises a second heat exchange air channel (61) and a second heat exchange flue gas channel (62), the outlet of the burner (9) is communicated with the inlet of the ammonia decomposition reaction flue gas channel (42), and provides heat energy for the decomposition of ammonia in the ammonia decomposition reactor (4), the outlet of the air compressor (20) is communicated with the inlet of the second heat exchange air channel (61), the outlet of the ammonia decomposition reaction flue gas channel (42) is communicated with the inlet of the second heat exchange flue gas channel (62), and is used to preheat the air entering the second heat exchange air channel (61) through the air compressor (20), and the outlet of the second heat exchange flue gas channel (62) is communicated with the flue gas treatment and release unit (30), and is used to treat and release the flue gas after combustion and heat exchange.

3. The ammonia decomposition hydrogen production rapid start-up system according to claim 2, characterized in that: The system further comprises a gas mixer (8), wherein the outlet of the second heat exchange flue gas channel (62), the mixed gas outlet of the unpurified hydrogen channel (71), the gas outlet of the pure hydrogen collector (10) and the gas outlet of the plasma ammonia decomposition hydrogen production reactor (5) are respectively connected to the inlet of the gas mixer (8), and the hot air after heat exchange through the second heat exchanger (6), the unpurified hydrogen through the unpurified hydrogen channel (71), the pure hydrogen collected in the pure hydrogen collector (10), and the hydrogen decomposed by the plasma ammonia decomposition hydrogen production reactor (5) enter the gas mixer (8), and the mixed gas flowing out after mixing in the gas mixer (8) flows into the burner (9), and is ignited and burned in the burner (9) to generate high-temperature flue gas.

4. The ammonia decomposition hydrogen production rapid start-up system according to claim 3, characterized in that: The separation membrane used for purification in the membrane separation purifier (7) is a selective hydrogen permeable membrane, which can efficiently separate hydrogen from other gases; after the gas flows out from the outlet of the product gas channel (32) of the first heat exchanger (3), it enters the unpurified hydrogen channel (71) of the purifier (7), and then the gas will be split into two directions, wherein the hydrogen that passes through the selective hydrogen permeable membrane enters the purified hydrogen channel (72), and the unpurified gas that does not pass through the selective hydrogen permeable membrane, containing hydrogen, nitrogen and a small amount of unreacted ammonia, enters the gas mixer (8).

5. The ammonia decomposition hydrogen production rapid start-up system according to claim 1, characterized in that: The ammonia decomposition reactor (4) is a fixed bed reactor. An ammonia decomposition catalyst is filled in the ammonia channel of the ammonia decomposition reactor (4). The reactant ammonia gas flow flows out of the first heat exchanger (3) and enters the ammonia channel of the ammonia decomposition reactor (4). The reactant ammonia gas flows through the ammonia decomposition catalyst and is converted into decomposition products to obtain hydrogen and nitrogen. The plasma ammonia decomposition hydrogen production reactor (5) comprises a plasma reactor ammonia gas channel (51) and a plasma generator (52). The plasma ammonia decomposition hydrogen production reactor (5) is a fixed bed reactor. An ammonia decomposition catalyst is filled in the plasma reactor ammonia gas channel (51). The plasma generator (52) is installed on the outer wall of the ammonia channel (51) of the plasma reactor, and the plasma generator (52) adopts a dielectric barrier discharge technology route; after the reactant ammonia gas flow flows out of the first heat exchanger (3), a part enters the ammonia channel (41) of the ammonia decomposition reactor (4), and the other part enters the plasma reactor ammonia channel (51) of the plasma ammonia decomposition hydrogen production reactor (5), and the ratio of the former flow rate to the latter flow rate is in the range of 5-40 times.

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