Curved panel structure thin film micro-channel reactor and mobile ammonia decomposition low-temperature hydrogen production system

Abstract

This invention discloses a curved-panel structure thin-film microchannel reactor and a mobile ammonia decomposition low-temperature hydrogen production system. The thin-film microchannel reactor includes an insulated shell with an inlet and an outlet, and a corrugated single-layer aluminum alloy sheet stacked within the insulated shell. Two sides of the single-layer aluminum alloy sheet are respectively provided with a 0.2-1 mm Ru / γ-Al2O3 catalyst film. The microchannel spacing formed between the single-layer aluminum alloy sheets is 0.1-0.5 mm. The microchannels are tortuous in the direction from the inlet to the outlet. The system includes an ammonia storage tank, a residual ammonia adsorption tower, an alloy membrane hydrogen purification device, a heat exchange device, and the thin-film microchannel reactor. In this invention, the raw material ammonia reacts with the Ru / γ-Al2O3 catalyst film as it passes through the microchannels of the reactor, decomposing into a H2+N2 mixture. This achieves lightweight and miniaturized design of the thin-film microchannel reactor. The high thermal conductivity of the single-layer aluminum alloy sheet ensures uniform reaction temperature in the transverse and longitudinal directions of the bed, with a temperature difference of less than 5°C, achieving low-temperature and efficient ammonia decomposition hydrogen production, with an NH3 conversion rate of over 99.5%.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production and supply technology, specifically to a curved panel structure thin-film microchannel reactor and a mobile ammonia decomposition low-temperature hydrogen production system. Background Technology

[0002] As a clean energy source, hydrogen (H2) is widely used in zero-emission vehicles, auxiliary power units, and industrial applications. However, significant risks remain in hydrogen storage and transportation methods, severely hindering the further development of hydrogen-based fuel cell technology. Ammonia (NH3), as a hydrogen carrier, is considered an important liquid fuel. Due to its high hydrogen content (17.8%) and ease of liquefaction, ammonia decomposition technology allows for on-site hydrogen production and use, thus avoiding the cumbersome hydrogen transportation and storage processes.

[0003] The "ammonia-hydrogen" green energy route combines renewable energy with the hydrogen energy industry, using ammonia as an energy storage or hydrogen storage carrier to develop a "clean and efficient synthetic ammonia - economical and safe ammonia energy storage and transportation - carbon-free and efficient ammonia hydrogen utilization" "zero carbon" circular technology route, providing an important technical approach to achieve the "dual carbon" goal.

[0004] The decomposition of ammonia is a mild endothermic process that produces hydrogen and nitrogen. Ammonia decomposition for hydrogen production is divided into traditional and new technologies. Traditional ammonia decomposition for hydrogen production has drawbacks such as high energy consumption (650-850℃), high investment costs for equipment construction, and poor economic applicability. The economic cost of new low-temperature ammonia decomposition for hydrogen production is basically equivalent to that of methane steam reforming for hydrogen production, and at least 15% lower than that of other zero-carbon routes (wind electrolysis, photovoltaic electrolysis, solar thermal decomposition, etc.).

[0005] The use of ammonia (NH3) as a carbon-free H2 carrier has attracted attention worldwide. In fact, NH3 decomposition is one of the most promising fuel processing technologies for PEM fuel cell applications. From the perspectives of cost, system volume, and logistics, NH3 decomposition is particularly attractive as a fuel processing technology for PEM fuel cell applications: 2NH3 → N2 + 3H2, ΔH 0 = 46.19 kcal / mol. Importantly, PEM fuel cells have very low tolerance for residual NH3 (0.1 ppm NH3). If the residual NH3 concentration exceeds the specified limit, the anode catalyst deactivates, subsequently leading to a loss of cell performance. This places very high demands on residual ammonia removal technology.

[0006] Existing fixed-bed reactors for NH3 decomposition are bulky and cannot meet the performance standards for mobile vehicle-mounted systems using NH3 cracking for hydrogen production as a hydrogen supply unit as stipulated by the US Department of Energy (USDOE), due to issues such as heavy weight, large size, and long start-up time. It is essential to develop and develop miniaturized, lightweight, and highly efficient ammonia cracking hydrogen production microchannel reactors to reduce the size and weight of H2 production systems and meet the necessary requirements for portable, mobile, bus, and shipboard applications.

[0007] The development of NH3 decomposition infrastructure for distributed power generation via PEM fuel cells mainly focuses on catalyst development. Traditional Ni-based catalysts for ammonia cracking have high activity and low cost, but their cracking temperatures are as high as 650–850°C. Ruthenium (Ru) is considered the best catalyst for NH3 decomposition, exhibiting excellent low-temperature ammonia cracking characteristics and achieving high-conversion ammonia cracking at 450–550°C, but its price is relatively high. Summary of the Invention

[0008] To address the aforementioned technical problems, overcome the drawbacks of conventional ammonia cracking reactors in the prior art, such as large volume and heavy weight, reduce costs, and achieve efficient and safe hydrogen production and supply, this invention provides a curved panel structure thin-film microchannel reactor and a mobile ammonia decomposition low-temperature hydrogen production system for miniaturized, lightweight, and mobile ammonia decomposition hydrogen production.

[0009] The technical solution adopted is as follows:

[0010] On one hand, the present invention provides a curved panel structure thin film microchannel reactor, the thin film microchannel reactor comprising an insulated shell having an inlet and an outlet, and a plurality of single-layer aluminum alloy thin plates stacked within the insulated shell. Each single-layer aluminum alloy thin plate has a Ru / γ-Al2O3 catalyst thin film on both sides, and the microchannel spacing formed by adjacent single-layer aluminum alloy thin plates is 0.1 mm to 0.5 mm. The inlet and outlet of the thin film microchannel reactor are connected to the microchannels, and the microchannels are tortuous in the direction from the inlet to the outlet.

[0011] Preferably, the single-layer aluminum alloy sheet has a wavy curved surface with a radius of 5° to 30° and a thickness of 2mm to 10mm, and the microchannel forms a wavy channel with a radius of 5° to 30°.

[0012] The thickness of the Ru / γ-Al2O3 catalyst film is 0.2 mm to 1 mm, and the catalyst in the Ru / γ-Al2O3 catalyst film is a Ru / γ-Al2O3 film catalyst with 1 to 5% Ru supported.

[0013] Preferably, the thin-film microchannel reactor contains 5 to 30 layers of single-layer aluminum alloy sheets, wherein the length of the single-layer aluminum alloy sheets is 50 mm to 1000 mm and the width is 50 mm to 1000 mm.

[0014] Furthermore, the inlet and outlet of the insulation shell are respectively provided with detachable material distribution trays, and the material distribution trays are formed with a number of micro-holes.

[0015] Furthermore, the method for preparing Ru / γ-Al2O3 catalyst films on the single-layer aluminum alloy sheet is as follows:

[0016] A paste-like slurry is prepared by mixing boehmite, tianqing powder, and 2% dilute nitric acid, and then uniformly coated on the surface of the single-layer aluminum alloy sheet to form a uniform coating of 0.2 to 1 mm.

[0017] The film was dried in an oven at 110°C for 12 hours and then calcined at 350~500°C for 4 hours to obtain a γ-Al2O3 film.

[0018] Prepare an aqueous solution of 1-5% RuCl3•3H2O, and load the precursor onto the γ-Al2O3 film using a saturated impregnation method;

[0019] The sample was dried in an oven at 110°C and then reduced with a 1 g / L NaBH4 solution, wherein the solvent of the NaBH4 solution was water and ethanol in a volume ratio of 1:1.

[0020] Ru / γ-Al2O3 thin film catalysts loaded with 1-5% Ru were prepared by washing with distilled water.

[0021] On the other hand, the present invention also provides a mobile ammonia decomposition low-temperature hydrogen production system. The system includes an ammonia storage tank, a residual ammonia adsorption tower, an alloy membrane hydrogen purification device, a heat exchange device, and a thin-film microchannel reactor. The raw ammonia in the ammonia storage tank is heated to 450°C~550°C by the heat exchange device and enters the thin-film microchannel reactor, where the ammonia is decomposed into an H2+N2 mixture containing 1000ppm~5000ppm residual ammonia. The H2+N2 mixture is heated to 20°C~30°C by the heat exchange device and enters the residual ammonia adsorption tower. The concentration of residual ammonia after adsorption and removal is less than 0.1ppm. The H2+N2 mixture after residual ammonia removal by the residual ammonia adsorption tower is then heated to 380°C~400°C by the heat exchange device and enters the alloy membrane hydrogen purification device, where high-purity hydrogen of more than 99.99% is obtained on the permeation side, and N2 is discharged on the separation side.

[0022] Preferably, the residual ammonia adsorbent in the residual ammonia adsorption tower is a 10-85% H3PO4 aqueous solution.

[0023] Preferably, the metal alloy membrane used to construct the H2+N2 mixed gas separation device in the alloy membrane hydrogen purification device is one of Pd alloy membrane, Nb alloy membrane, and V alloy membrane.

[0024] The technical solution of the present invention has the following advantages:

[0025] A. The compact thin-plate reactor provided by this invention has a microchannel structure formed by several single-layer aluminum alloy thin plates. A Ru / γ-Al2O3 catalyst film is provided on one or both sides of each single-layer aluminum alloy thin plate. When the raw material ammonia passes through the microchannel, it reacts with the Ru / γ-Al2O3 catalyst film and decomposes into a H2+N2 mixture. This achieves the lightweight and miniaturization of the thin-plate microchannel reactor. Moreover, the single-layer aluminum alloy thin plate has high thermal conductivity, with a thermal conductivity as high as 230 W / (m K) at 300°C. The ammonia decomposition reaction is an endothermic reaction. The high thermal conductivity makes the reaction temperature of the bed in the thin-plate microchannel reactor uniform in both the transverse and longitudinal directions, with a temperature difference of less than 5°C.

[0026] B. This invention involves uniformly coating a pseudo-boehmite precursor onto a single-layer aluminum alloy sheet with high thermal conductivity, followed by high-temperature calcination to form a γ-Al2O3 support with a large porous structure and a large specific surface area. A 1-5% / γ-Al2O3 low-temperature ammonia cracking catalyst is prepared in situ via a saturated impregnation method. Combined with a microchannel spacing of 0.1 mm to 0.5 mm and a corrugated single-layer aluminum alloy sheet, the raw material ammonia forms turbulence in the thin-film microchannel reactor, fully contacting and reacting rapidly with the catalyst film. This allows for low-temperature ammonia cracking at 450℃ to 550℃, with an NH3 conversion rate greater than 99.5%.

[0027] C. The present invention also provides a material distribution plate at the inlet and outlet of the heat insulation shell, and the material distribution plate is formed with a number of micropores, which can ensure that the heated raw material ammonia enters the shell evenly to complete the efficient cracking reaction.

[0028] D. This invention combines a thin-film microchannel reactor with an alloy membrane hydrogen purification device in a low-temperature hydrogen production system, using metal alloy membrane separation technology to replace the traditional PSA (Pressure Swing Adsorption) gas separation and purification technology. Existing PSA devices are large and heavy, limiting their use to large, fixed applications. In contrast, metal alloy membrane separation components are very small and lightweight, making them a key method for miniaturized, lightweight, mobile, and portable ammonia cracking hydrogen production. This invention combines a compact, modular thin-film microchannel reactor with a high-adsorption-capacity residual ammonia adsorption tower, and especially with a metal alloy membrane hydrogen purification device, forming a complete hydrogen production process. After system integration, it achieves a high degree of automation and is easily mounted on mobile devices such as heavy trucks, buses, ships, and even as a personal power source for soldiers. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This invention provides a single-layer aluminum alloy sheet with a regular curved surface structure.

[0031] Figure 2 This invention provides a Ru / γ-Al2O3 catalyst film with a macroporous structure and a large specific surface area.

[0032] Figure 3 This is a schematic diagram of the front cross section of the curved panel type thin film microchannel reactor provided by the present invention;

[0033] Figure 4 This is a schematic diagram of the curved panel type thin film microchannel reactor uniform plate structure provided by the present invention;

[0034] Figure 5 This is a schematic diagram of the process flow of the full-process ammonia decomposition hydrogen production system provided by the present invention.

[0035] The meanings of the symbols in the image are as follows:

[0036] 1-Insulation shell

[0037] 1a - Inlet, 1b - Outlet

[0038] 2-Single-layer aluminum alloy sheet

[0039] 3-Ru / γ-Al2O3 catalyst thin film

[0040] 4-Packaging tray

[0041] 41-Micropores

[0042] A - Thin-film microchannel reactor, a - Microchannel; B - Ammonia storage tank; C - Residual ammonia adsorption tower

[0043] D - Alloy membrane hydrogen purification device; E - Heat exchange device. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] like Figure 3 As shown, the present invention provides a curved panel structure thin-film microchannel reactor A, comprising an insulated shell 1 including an inlet 1a and an outlet 1b, and a plurality of single-layer aluminum alloy thin plates 2 stacked within the insulated shell 1. A Ru / γ-Al2O3 catalyst film 3 is provided on one or both sides of each single-layer aluminum alloy thin plate 2, and the spacing between the microchannels a formed by two adjacent single-layer aluminum alloy thin plates 2 is 0.1–0.5 mm. Preferably, the inlet 1a and outlet 1b of the thin-film microchannel reactor A are arranged along the length direction of the insulated shell 1, and a sealing weld is formed at both sides along the length direction of the single-layer aluminum alloy thin plates 2. Figure 1 As shown, the single-layer aluminum alloy sheet 2 has a thickness of 2mm-10mm and a wavy curved surface of 5°-30°, with a length of 100mm-1000mm and a width of 100mm-1000mm. The resulting microchannel a also exhibits a wavy shape from the inlet to the outlet, achieving lightweighting and miniaturization of the thin-film microchannel reactor. Because the thin-film microchannel reactor uses a wavy curved sheet, the raw material ammonia undergoes multiple direction changes from the inlet to the outlet, forming turbulence and significantly increasing the contact area between the raw material ammonia and the Ru / γ-Al2O3 catalyst film 3.

[0046] The single-layer aluminum alloy sheet provided by this invention undergoes surface treatment to form a double-sided rough surface, exhibiting excellent adhesion and bonding strength. For example... Figure 2 As shown, a 0.2mm-1mm pseudo-boehmite precursor film was uniformly coated on a single-layer aluminum alloy sheet. After in-situ drying at 110℃ and high-temperature calcination at 350~500℃, a γ-Al2O3 support film with macroporous structure and large specific surface area was formed. Finally, a 1-5%Ru / γ-alumina low-temperature ammonia cracking catalyst was prepared in-situ by saturated impregnation method.

[0047] The specific method for preparing the Ru / γ-Al2O3 catalyst film 3 on a single-layer aluminum alloy thin plate 2 is as follows:

[0048] Step 1: Prepare a paste-like slurry by mixing boehmite, tianqing powder, and 2% dilute nitric acid, and evenly coat it onto the surface of the single-layer aluminum alloy sheet to form a uniform coating of 0.2-1mm.

[0049] Step 2: Dry at 110℃ in an oven for 12 hours, and then calcine at 350~500℃ for 4 hours to obtain γ-Al2O3 film;

[0050] Step 3: Prepare an aqueous solution of 1-5% RuCl3•3H2O, and load the precursor onto the γ-Al2O3 film using the saturated impregnation method;

[0051] Step 4: Dry in an oven at 110°C, then reduce with a 1 g / L NaBH4 solution, wherein the solvent of the NaBH4 solution is water and ethanol in a volume ratio of 1:1.

[0052] Step 5: Wash with distilled water to prepare Ru / γ-Al2O3 thin film catalyst with 1-5% Ru loading.

[0053] like Figure 3 As shown, single-layer aluminum alloy sheets are stacked in an orderly manner and sealed by laser welding, forming microchannels with a thickness of 0.1mm to 0.5mm between the sheets. Several single-layer aluminum alloy sheets are assembled into a modular curved panel type thin film microchannel reactor with 5 to 30 stacked layers, which has a compact structure and forms microchannels with a high specific surface area.

[0054] To ensure uniform feeding, a feeding plate 4 with tens to thousands of micropores 41 is manufactured using precision machining technology at the ammonia material inlet (NH3) and outlet (H2, N2, residual ammonia), such as... Figure 4 As shown, this allows the material to enter the reactor uniformly, fully contact the catalyst film, and react rapidly, enabling ammonia cracking at a low temperature of 450–550℃, with an NH3 conversion rate greater than 99.5%.

[0055] like Figure 5 As shown, the present invention integrates a thin-film microchannel reactor A, an ammonia storage tank B, a residual ammonia adsorption tower C, an alloy membrane hydrogen purification device D, and a heat exchange device E to form a mobile ammonia decomposition low-temperature hydrogen production system.

[0056] The process flow is described as follows:

[0057] (1) The raw material NH3 is output from the ammonia storage tank B, and after passing through the heat exchange device E to reach the reaction inlet temperature of 450~550℃, it enters the thin film microchannel reactor A with a curved surface structure. After ammonia cracking, it produces a H2+N2 mixture containing 1000~5000ppm residual ammonia.

[0058] (2) After the mixed gas is heated to 20℃~30℃, it enters the residual ammonia adsorption tower C, where the residual ammonia is adsorbed and removed, and the concentration of residual ammonia is less than 0.1ppm;

[0059] (3) After heat exchange, the H2+N2 mixture is heated to 380℃~400℃ and enters the hydrogen purification unit. After passing through the metal alloy membrane separation component (Nb alloy membrane or V alloy membrane) in the alloy membrane hydrogen purification device D, high-purity hydrogen of more than 99.99% is obtained on the permeation side, which meets the hydrogen purity requirements for PEM hydrogen fuel cells. On the separation side, N2 is discharged and the residual ammonia content is less than 0.1ppm.

[0060] By combining a compact, modular thin-film microchannel reactor with a high-adsorption-capacity residual ammonia adsorption tower, especially with a metal alloy membrane hydrogen purification device, a complete process flow is formed. Then, through system integration and optimization, and high automation, a miniaturized, lightweight, mobile, and portable ammonia cracking hydrogen production and supply can be achieved. This can be mounted on mobile devices, such as heavy trucks, buses, ships, and mobile power supplies for individual soldiers. Example 1

[0061] The single-layer aluminum alloy sheet is a wavy curved plate structure with a 5° included angle, 2mm thick, 50mm long, and 50mm wide. The microchannels between the single-layer aluminum alloy sheets are spaced 0.1mm apart, with up to 10 layers stacked together to construct a modular curved plate-type thin-film microchannel reactor. The internal volume of the insulated shell is 0.052L (52cm³). 3 ).

[0062] A 0.2 mm thick film of supported 2.2% Ru / γ-Al₂O₃ ammonia cracking catalyst with a catalyst volume of 10 cm⁻¹. 3 Sixty micropores were created at the ammonia material inlet (NH3) and outlet (H2, N2, residual ammonia) using precision machining technology (see illustration). Figure 4 This allows the material to enter the insulated shell uniformly. Utilizing the curved structure inside the shell, turbulent flow is created, ensuring full contact and rapid reaction with the catalyst film. The raw material NH3 is heated to 450℃ through heat exchange. With an NH3 feed rate of 40–80 mL / min and an inlet pressure of 1.2 bar, the conversion rate of NH3 in low-temperature ammonia cracking under these conditions is 99.52%, and the residual ammonia in the cracked gas is 4800 ppm. This demonstrates that the curved-panel structure of the thin-film microchannel reactor possesses high mass transfer and heat transfer efficiency.

[0063] After the mixed gas is cooled to 20℃~30℃ by heat exchange, it enters the residual ammonia adsorption tower. A 20% H3PO4 aqueous solution is used as the adsorbent, and the residual ammonia is efficiently removed. No residual ammonia can be detected in the H2+N2 mixed gas at the outlet.

[0064] The H2+N2 mixture is then heated to 380℃-400℃ after heat exchange and pressurized to 6 bar before entering the alloy membrane hydrogen purification unit. Using an Nb metal alloy membrane separation component, high-purity hydrogen of over 99.99% is obtained on the permeate side, producing 1.8~3.6 liters of high-purity hydrogen of over 99.99% per hour. The hydrogen purity meets the requirements for hydrogen purity used in PEM hydrogen fuel cells. Example 2

[0065] The microchannels formed between the single-layer aluminum alloy sheets have a spacing of 0.5 mm. Thirty single-layer aluminum alloy sheets are assembled into a modular curved panel type thin-film microchannel reactor. The single-layer aluminum alloy sheets are aluminum alloys with a 10° wavy curved plate structure, 3 mm thick, 500 mm long, and 500 mm wide. The internal volume of the insulating shell is 26.25 L. Including the heat insulation layer and the internal heat exchange device, the actual volume of the insulating shell is 35 L.

[0066] A 0.2 mm thick film of supported 3.0% Ru / γ-Al₂O₃ ammonia cracking catalyst. The volume of the film catalyst is 3 L (usage). 300 micropores (see diagram) are created at the ammonia feed inlet (NH₃) and outlet (H₂, N₂, residual ammonia) using precision machining techniques. Figure 4 This allows the material to enter the insulated shell uniformly. Utilizing the curved structure inside the shell, turbulent flow is created, ensuring full contact and rapid reaction with the catalyst film. The raw material NH3 is heated to 480℃ through heat exchange. With an NH3 feed rate of 600-800 mL / min and an inlet pressure of 1.3 bar, under these conditions, the conversion rate of NH3 in low-temperature ammonia cracking is 99.6%, and the residual ammonia in the cracked gas is 4000 ppm. This demonstrates that the curved-panel structure of the thin-film microchannel reactor possesses high mass transfer and heat transfer efficiency.

[0067] After the mixed gas is cooled to 20-30℃ by heat exchange, it enters the residual ammonia adsorption tower. A 40% H3PO4 aqueous solution is used as the adsorbent, and the residual ammonia is efficiently removed. The residual ammonia content of the H2 and N2 mixed gas at the outlet is reduced to 0.1ppm.

[0068] The H2+N2 mixture is heated to 380-400℃ and pressurized to 8 bar before entering the alloy membrane hydrogen purification unit. Using an Nb metal alloy membrane separation module, high-purity hydrogen of over 99.99% is obtained on the permeate side, producing 26-35 L of hydrogen per hour. The purity meets the requirements for hydrogen purity used in PEM hydrogen fuel cells. Example 3

[0069] The microchannels formed between the single-layer aluminum alloy sheets have a spacing of 0.2 mm. Fifteen single-layer aluminum alloy sheets are assembled into a modular curved panel type thin-film microchannel reactor. The single-layer aluminum alloy sheet is an aluminum alloy with a wavy curved plate structure featuring a 20° included angle, and is 6 mm thick, 1000 mm long, and 1000 mm wide. The reactor volume is 96 L.

[0070] A 0.2 mm thick film of a supported 3.0% Ru / γ-Al₂O₃ ammonia cracking catalyst was constructed, with a catalyst volume of 6 L. 666 micropores were created at the ammonia feed inlet (NH₃) and outlet (H₂, N₂, residual ammonia) using precision machining techniques (see diagram). Figure 4This allows the material to enter the insulated shell uniformly. Utilizing the curved structure inside the shell, turbulent flow is created, ensuring full contact and rapid reaction with the catalyst film. The raw material NH3 is heated to 550℃ through heat exchange. With an NH3 feed rate of 2000-4000 mL / min and an inlet pressure of 1.4 bar, the conversion rate of NH3 in low-temperature ammonia cracking under these conditions is 99.72%, and the residual ammonia in the cracked gas is 2800 ppm. This demonstrates that the curved-panel structure of the thin-film microchannel reactor possesses high mass transfer and heat transfer efficiency.

[0071] After the mixed gas is cooled to 20-30℃ by heat exchange, it enters the residual ammonia adsorption tower. A 60% H3PO4 aqueous solution is used as the adsorbent, and the residual ammonia is efficiently removed. The residual ammonia content of the H2 and N2 mixed gas at the outlet is reduced to 0.1ppm.

[0072] After heat exchange, the H2+N2 mixture is heated to 380℃-400℃ and pressurized to 10 bar before entering the alloy membrane hydrogen purification device. Using an Nb metal alloy membrane separation component, high-purity hydrogen of over 99.99% is obtained on the permeate side, producing 88~160L of hydrogen per hour, with purity meeting the requirements for hydrogen purity in PEM hydrogen fuel cells. Example 4

[0073] The microchannels formed between the single-layer aluminum alloy sheets have a spacing of 0.3 mm. Five single-layer aluminum alloy sheets are assembled into a modular curved panel type thin-film microchannel reactor. The single-layer aluminum alloy sheet is an aluminum alloy with a wavy curved plate structure featuring a 30° included angle, and has a thickness of 10 mm, a length of 100 mm, and a width of 100 mm. The reactor volume is 0.53 L.

[0074] A 1 mm thick film of supported 5% Ru / γ-Al₂O₃ ammonia cracking catalyst with a catalyst volume of 0.02 L was used. 100 micropores were precisely machined at the ammonia feed inlet (NH₃) and outlet (H₂, N₂, residual ammonia) to ensure uniform feed into the insulated shell. The curved surface structure of the insulated shell created turbulent flow, allowing for full contact and rapid reaction with the catalyst film. The NH₃ feedstock was heated to 500 °C via heat exchange. With an NH₃ feed rate of 50-100 mL / min and an inlet pressure of 1.3 bar, the low-temperature ammonia cracking conversion rate of NH₃ under these conditions was 99.8%, and the residual ammonia in the cracked gas was 2000 ppm. This demonstrates that the curved panel structure of the film microchannel reactor exhibits high mass transfer and heat transfer efficiency.

[0075] After the mixed gas is cooled to 20-30℃ by heat exchange, it enters the residual ammonia adsorption tower. 85% H3PO4 aqueous solution is used as the adsorbent, and the residual ammonia is efficiently removed. The residual ammonia content of the H2 and N2 mixed gas at the outlet is reduced to 0.1ppm.

[0076] After heat exchange, the H2+N2 mixture is heated to 380-400℃ and pressurized to 10 bar before entering the alloy membrane hydrogen purification device. Using a Pd alloy membrane separation component, high-purity hydrogen of over 99.99% is obtained on the permeate side, producing 2-4L of hydrogen per hour, with purity meeting the requirements for hydrogen purity in PEM hydrogen fuel cells. Example 5

[0077] The microchannels formed between the single-layer aluminum alloy sheets have a spacing of 0.2 mm. Twenty single-layer aluminum alloy sheets are assembled into a modular curved panel type thin-film microchannel reactor. The single-layer aluminum alloy sheet is an aluminum alloy with a wavy curved plate structure featuring a 30° included angle, and has a thickness of 6 mm, a length of 300 mm, and a width of 300 mm. The reactor volume is 11.16 L.

[0078] A 0.8 mm thick film of supported 1% Ru / γ-Al₂O₃ ammonia cracking catalyst with a catalyst volume of 0.14 L was used. 260 micropores were precisely machined at the ammonia feed inlet (NH₃) and outlet (H₂, N₂, residual ammonia) to ensure uniform feed into the insulated shell. The curved surface structure of the insulated shell created turbulent flow, allowing for full contact and rapid reaction with the catalyst film. The NH₃ feedstock was heated to 550 °C via heat exchange. With an NH₃ feed rate of 600-1000 mL / min and an inlet pressure of 1.2 bar, the low-temperature ammonia cracking conversion rate of NH₃ under these conditions was 99.86%, and the residual ammonia in the cracked gas was 1400 ppm. This demonstrates that the curved-panel structure of the film microchannel reactor exhibits high mass transfer and heat transfer efficiency.

[0079] After the mixed gas is cooled to 20-30℃ by heat exchange, it enters the residual ammonia adsorption tower. A 10% H3PO4 aqueous solution is used as the adsorbent, and the residual ammonia is efficiently removed. The residual ammonia content of the H2 and N2 mixed gas at the outlet is reduced to 0.1ppm.

[0080] After heat exchange, the H2+N2 mixture is heated to 380-400℃ and pressurized to 10 bar before entering the alloy membrane hydrogen purification device. High-purity hydrogen of over 99.99% is obtained on the permeate side using a V alloy membrane separation component, producing 26-43L of hydrogen per hour. The purity meets the hydrogen purity requirements for PEM hydrogen fuel cells.

[0081] Any aspects not covered in this invention are applicable to existing technologies.

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A curved panel-type thin-film microchannel reactor, characterized in that, The thin-film microchannel reactor (A) includes an insulated shell (1) with an inlet (1a) and an outlet (1b) and a plurality of single-layer aluminum alloy sheets (2) stacked inside the insulated shell (1). Ru / γ-Al2O3 catalyst films (3) are respectively provided on both sides of the single-layer aluminum alloy sheets (2). The spacing between the microchannels (a) formed by two adjacent layers of single-layer aluminum alloy sheets (2) is 0.1 mm to 0.5 mm. The inlet (1a) and outlet (1b) of the thin-film microchannel reactor (A) are connected to the microchannels (a). The microchannels (a) are tortuous in the direction from the inlet to the outlet. The single-layer aluminum alloy sheet (2) has a wavy curved surface with a 5° to 30° angle and a thickness of 2 mm to 10 mm. The microchannel (a) forms a wavy channel with a 5° to 30° angle. The inlet (1a) and outlet (1b) of the heat insulation shell (1) are respectively provided with a detachable material distribution plate (4), and the material distribution plate (4) is formed with a number of micro holes (41).

2. The curved panel structure thin-film microchannel reactor according to claim 1, characterized in that, The thickness of the Ru / γ-Al2O3 catalyst film (3) is 0.2 mm to 1 mm, and the catalyst in the Ru / γ-Al2O3 catalyst film (3) is a Ru / γ-Al2O3 film catalyst supported with 1 to 5% Ru.

3. The curved panel structure thin-film microchannel reactor according to claim 1 or 2, characterized in that, The thin-film microchannel reactor (A) contains 5 to 30 layers of single-layer aluminum alloy thin plates (2), the length of which is 50 mm to 1000 mm and the width of which is 50 mm to 1000 mm.

4. The curved panel structure thin-film microchannel reactor according to claim 1, characterized in that, Method for preparing Ru / γ-Al2O3 catalyst film (3) on the single-layer aluminum alloy sheet (2): A paste-like slurry is prepared by mixing boehmite, tianqing powder, and 2% dilute nitric acid, and then uniformly coated on the surface of the single-layer aluminum alloy sheet to form a uniform coating of 0.2mm to 1mm. The film was dried in an oven at 110°C for 12 hours, and then calcined at 350°C to 500°C for 4 hours to obtain a γ-Al2O3 film. Prepare an aqueous solution of 1-5% RuCl3·3H2O and load the precursor onto the γ-Al2O3 film using the saturated impregnation method; The sample was dried in an oven at 110°C and then reduced with a 1 g / L NaBH4 solution, wherein the solvent of the NaBH4 solution was water and ethanol in a volume ratio of 1:

1. Ru / γ-Al2O3 thin film catalysts loaded with 1-5% Ru were prepared by washing with distilled water.

5. A mobile ammonia decomposition low-temperature hydrogen production system, characterized in that, The system includes an ammonia storage tank (B), a residual ammonia adsorption tower (C), an alloy membrane hydrogen purification device (D), a heat exchange device (E), and a thin-film microchannel reactor (A) as described in any one of claims 1-4. The raw ammonia in the ammonia storage tank (B) is heated to 450°C~550°C by the heat exchange device (E) and enters the thin-film microchannel reactor (A), where the ammonia is cracked into an H2+N2 mixture containing 1000ppm~5000ppm residual ammonia. The H2+N2 mixture is heated to 20°C~30°C by the heat exchange device (E) and enters the residual ammonia adsorption tower (C). The concentration of the mixture after adsorption and removal is less than 0.1ppm. The H2+N2 mixture after residual ammonia removal by the residual ammonia adsorption tower (C) is then heated to 380°C~400°C by the heat exchange device (E) and enters the alloy membrane hydrogen purification device (D), where high-purity hydrogen of over 99.99% is obtained on the permeation side, and N2 is vented on the separation side.

6. The mobile ammonia decomposition low-temperature hydrogen production system according to claim 5, characterized in that, The residual ammonia adsorbent in the residual ammonia adsorption tower (C) is a 10-85% H3PO4 aqueous solution.

7. The mobile ammonia decomposition low-temperature hydrogen production system according to claim 5, characterized in that, The metal alloy membrane used in the alloy membrane hydrogen purification device (D) for constructing the separation of H2+N2 mixed gas is one of Pd alloy membrane, Nb alloy membrane, and V alloy membrane.

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