Ammonia decomposition microchannel reaction plate, reactor and ammonia decomposition hydrogen production method

Abstract

The application provides an ammonia decomposition micro-channel reaction plate and reactor and an ammonia decomposition hydrogen production method, and relates to the field of ammonia decomposition hydrogen production.The ammonia decomposition micro-channel reaction plate comprises a reaction plate body and a micro-channel structure formed on the reaction plate body, and the micro-channel structure comprises a preheating chamber, a micro-reaction channel, a gas-liquid separation channel and a gas collection chamber which are sequentially connected from bottom to top.The preheating, decomposition, gas-liquid separation and product collection are integrated, the structure is simple, the heat distribution is reasonably utilized, the input power consumption of fluid is reduced, and the heat use efficiency is improved.The ammonia decomposition micro-channel reactor comprises a first cover plate, a first graphite sheet, an ammonia decomposition micro-channel reaction plate, a second graphite sheet and a second cover plate which are sequentially and layerwisely arranged, the reactor structure is compact, can be used in small-flow hydrogen production occasions, and is assembled in a layering mode, so that the disassembly, assembly and catalyst loading are simple;the degree of modularization is high, the reaction scale can be increased by stacking the reaction plates;the structure is simple, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of ammonia decomposition hydrogen production technology, specifically to an ammonia decomposition microchannel reaction plate and reactor, and a method for ammonia decomposition hydrogen production. Background Technology

[0002] Energy is the material foundation for the rapid development of society and the economy. With the increasing depletion of non-renewable energy sources such as fossil fuels, there is an urgent need to develop clean energy sources that can replace fossil fuels. Hydrogen energy is hailed as the most promising secondary energy source of the 21st century. The enthalpy of combustion of H2 is 142 MJ / kg, and the combustion product is water, which conforms to the concept of green chemistry with zero pollution and zero emissions.

[0003] Compared with hydrogen production from hydrogen storage feedstocks such as natural gas, liquefied petroleum gas, and methanol, hydrogen production from ammonia decomposition (2NH3=N2+3H2) has the following advantages: (1) NH3 can be stored and transported in liquid form at 20℃ and 0.8MPa; (2) NH3 has a large energy density (3000Wh / kg) and a high hydrogen capacity (17wt.%); (3) The decomposition products of NH3 are only hydrogen and nitrogen, with no CO. x and NO x (3) With the selection of a suitable absorbent, undecomposed NH3 can be effectively absorbed; (4) The production, storage and transportation technologies of NH3 are mature. Therefore, NH3 is an efficient, clean and safe carrier for hydrogen production, storage and transportation.

[0004] Current ammonia decomposition hydrogen production reactors mostly employ pyrolysis furnaces. For example, Chinese patent document CN205011382U discloses an ammonia decomposition hydrogen production device, including a shell, a heat exchanger, and a decomposition furnace. By exchanging heat between a high-temperature hydrogen-nitrogen mixture and gaseous ammonia in the heat exchanger, the temperature of the ammonia entering the decomposition furnace is increased, which is beneficial for the decomposition of gaseous ammonia. Another example is Chinese patent document CN210528460U, which discloses an ammonia decomposition hydrogen production apparatus, including a heat exchanger, a pyrolysis furnace, a cooler, and two dryers. These dryers can be regenerated using either hydrogen purging or nitrogen, offering greater flexibility. However, using a pyrolysis furnace has disadvantages such as large size and low heat transfer efficiency.

[0005] Microreactors have broad application prospects due to their small size, high heat transfer efficiency, short response time, and uniform temperature distribution. How to provide a microchannel reactor for ammonia decomposition with simple structure, high uniformity of flow rate and concentration distribution, and low fluid flow pressure has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects of large volume and low heat transfer efficiency of the ammonia decomposition hydrogen production reactor in the prior art, thereby providing an ammonia decomposition microchannel reaction plate and reactor and an ammonia decomposition hydrogen production method.

[0007] In a first aspect, the present invention provides an ammonia decomposition microchannel reaction plate, comprising a reaction plate body and a microchannel structure formed on the reaction plate body. The microchannel structure comprises a preheating chamber, a micro-reaction channel, a gas-liquid separation channel and a gas collection chamber connected sequentially from bottom to top. A liquid-blocking baffle is provided in the gas-liquid separation channel, and a channel for gas to pass through is left between the liquid-blocking baffle and the side wall of the gas-liquid separation channel.

[0008] Furthermore, the liquid-blocking baffle is in the shape of a triangular prism, and one of the tips of the triangular prism faces the micro-reaction channel.

[0009] Furthermore, the gas-liquid separation channel includes an inlet transition section, a straight pipe section, and an outlet section connected sequentially from bottom to top. The inlet transition section is connected to the micro-reaction channel and its width gradually increases from bottom to top. The width of the outlet section is smaller than that of the straight pipe section. The liquid-blocking baffle is located at the junction of the inlet transition section and the straight pipe section.

[0010] Furthermore, the preheating chamber and the gas collection chamber are rectangular grooves. The preheating chamber has a width of 30-35 mm and a length of 10-12 mm, and the gas collection chamber has a width of 30-35 mm and a length of 10-12 mm. The micro-reaction channel has a width of 2-4 mm and a length of 60-65 mm. In the gas-liquid separation channel, the inlet width of the inlet transition section is 2-4 mm, the outlet width is 4-8 mm, and the length is 10-15 mm. The straight pipe section has a width of 4-8 mm and a length of 25-30 mm. The outlet section has a width of 2-4 mm and a length of 5-10 mm. The liquid-blocking baffle has a width of 2-4 mm.

[0011] Furthermore, the number of micro-reaction channels and gas-liquid separation channels is 5-8.

[0012] Furthermore, the depth of the preheating chamber, micro-reaction channel, gas-liquid separation channel, and gas collection chamber is 2 mm.

[0013] Furthermore, the ammonia decomposition microchannel reaction plate further includes a heating rod and a thermocouple, which are embedded in the reaction plate body and located on the back side of the microchannel structure.

[0014] Furthermore, the reaction plate body is made of stainless steel.

[0015] Furthermore, the microreaction channel is a straight-tube microreaction channel.

[0016] Furthermore, the microreaction channel is loaded with Ru / La 0.4 Ce 0.6 O 1.8 catalyst.

[0017] Secondly, the present invention provides an ammonia decomposition microchannel reactor, including the aforementioned ammonia decomposition microchannel reaction plate.

[0018] Furthermore, the ammonia decomposition microchannel reactor includes a first cover plate, a first graphite sheet, the ammonia decomposition microchannel reaction plate, a second graphite sheet, and a second cover plate stacked sequentially. The first and second graphite sheets seal the front and back sides of the ammonia decomposition microchannel reaction plate. The first cover plate has a cover plate outlet, and the first graphite sheet has a graphite sheet outlet. Both the cover plate outlet and the graphite sheet outlet are connected to the gas collection chamber. The second cover plate has a cover plate inlet, and the second graphite sheet has a graphite sheet inlet. Both the cover plate inlet and the graphite sheet inlet are connected to the preheating chamber.

[0019] Furthermore, both the first cover plate and the second cover plate are made of stainless steel.

[0020] Furthermore, the first cover plate and the second cover plate are connected by bolts.

[0021] Furthermore, the thickness of the first cover plate and the second cover plate is 5mm.

[0022] Furthermore, the thickness of the first graphite sheet and the second graphite sheet is 2 mm.

[0023] Furthermore, the first cover plate has a first cover plate positioning hole, the first graphite sheet has a first graphite sheet positioning hole, the ammonia decomposition microchannel reaction plate has a reaction plate positioning hole, the second graphite sheet has a second graphite sheet positioning hole, and the second cover plate has a second cover plate positioning hole. The first cover plate positioning hole, the first graphite sheet positioning hole, the reaction plate positioning hole, the second graphite sheet positioning hole, and the second cover plate positioning hole are interconnected.

[0024] Furthermore, the first cover plate has a first cover plate bolt mounting hole, and the second cover plate has a second cover plate bolt mounting hole. The bolt passes through the first cover plate bolt mounting hole and the second cover plate bolt mounting hole and is fastened by a nut.

[0025] Furthermore, an air outlet pipe is connected to the first cover plate, and the air outlet pipe is connected to the outlet of the cover plate. A feed pipe is connected to the second cover plate, and the feed pipe is connected to the inlet of the cover plate.

[0026] Thirdly, the present invention provides a method for producing hydrogen by ammonia decomposition, which is carried out using the aforementioned ammonia decomposition microchannel reactor.

[0027] Furthermore, the reaction temperature is 300–400℃, and the space velocity is 1500–10000 h⁻¹. -1 .

[0028] The technical solution of this invention has the following advantages:

[0029] 1. The ammonia decomposition microchannel reaction plate provided by this invention integrates preheating, decomposition, gas-liquid separation, and product collection into one unit. Ammonia gas, the reactant, is preheated in the preheating chamber and then enters the micro-reaction channel. Under the action of a catalyst, it undergoes a decomposition reaction to generate hydrogen and nitrogen. The hydrogen and nitrogen, along with the mixed ammonia gas, enter the gas-liquid separation channel. Unreacted ammonia gas encounters a liquid-blocking baffle, condenses into droplets, and flows back into the micro-reaction channel for further decomposition, thus achieving the separation of ammonia and product gases. Hydrogen and nitrogen gas flow out through a pre-reserved gas channel between the liquid-blocking baffle and the sidewall of the gas-liquid separation channel, and finally enter the gas collection chamber. By combining multiple steps into one unit, the structure is simple, rationally utilizes heat distribution, reduces fluid input power consumption, and improves heat utilization efficiency.

[0030] 2. The ammonia decomposition microchannel reaction plate provided by the present invention has a liquid-blocking baffle in the shape of a triangular prism, with one tip of the triangular prism facing the micro-reaction channel. This structure enhances the separation capability of ammonia and gas, allows unreacted ammonia to flow back, increases reaction efficiency, and reduces subsequent separation energy consumption.

[0031] 3. The ammonia decomposition microchannel reaction plate provided by the present invention includes an inlet transition section, a straight pipe section, and an outlet section connected sequentially from bottom to top in the gas-liquid separation channel. By setting the inlet transition section so that the width of the straight pipe section is greater than that of the micro-reaction channel, and controlling the width of the outlet section to be less than that of the straight pipe section, the structure is more conducive to the outflow of product gas, thereby further promoting ammonia decomposition, accelerating the reaction process, and improving the product gas yield.

[0032] 4. The ammonia decomposition microchannel reactor provided by the present invention includes a first cover plate, a first graphite sheet, an ammonia decomposition microchannel reaction plate, a second graphite sheet, and a second cover plate stacked sequentially. The reactor has a compact structure and can be used in low-flow hydrogen production applications. It is assembled in a stacked manner, making disassembly, assembly, and catalyst loading simple. It has a high degree of modularity, and the reaction scale can be increased by stacking reaction plates. It has a simple structure, low cost, and precise temperature control, resulting in a small temperature gradient inside the reactor. This provides an excellent reaction environment for the catalyst and effectively improves the heat and mass transfer performance and reaction efficiency of the reactor. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art 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.

[0034] Figure 1 This is a schematic diagram of the structure of the ammonia decomposition microchannel reaction plate provided in Embodiment 1 of the present invention;

[0035] Figure 2 This is a schematic diagram of the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the first cover plate in the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of the second cover plate in the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention;

[0038] Figure 5 This is a schematic diagram of the structure of the first graphite sheet in the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention;

[0039] Figure 6 This is a schematic diagram of the structure of the second graphite sheet in the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention;

[0040] Figure 7 The ammonia conversion rate of the ammonia decomposition microchannel reactor provided in Example 1 of the present invention under different catalysts;

[0041] Figure 8 The ammonia conversion rate of the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention at the reaction time;

[0042] Figure 9 The ammonia conversion rate of the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention at different space velocities;

[0043] Figure 10 The ammonia conversion rate of the ammonia decomposition microchannel reactor provided in Embodiment 1 of the present invention and two other reactors.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1-First cover plate; 11-First cover plate bolt mounting hole; 12-Gas outlet pipe; 13-First cover plate positioning hole; 2-First graphite sheet; 21-Graphite sheet outlet; 22-First graphite sheet positioning hole; 3-Ammonia decomposition microchannel reaction plate; 31-Preheating chamber; 32-Micro-reaction channel; 33-Gas-liquid separation channel; 34-Gas collection chamber; 35-Liquid-blocking baffle; 36-Heating rod through hole; 37-Thermocouple through hole; 38-Ammonia inlet; 39-Reaction plate positioning hole; 4-Second graphite sheet; 41-Graphite sheet inlet; 42-Second graphite sheet positioning hole; 5-Second cover plate; 51-Second cover plate bolt mounting hole; 52-Feed pipe; 53-Second cover plate positioning hole. Detailed Implementation

[0046] 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.

[0047] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] like Figure 1As shown, the present invention provides an ammonia decomposition microchannel reaction plate, including a reaction plate body and a microchannel structure formed on the reaction plate body. The microchannel structure includes a preheating chamber 31, a micro-reaction channel 32, a gas-liquid separation channel 33 and a gas collection chamber 34 connected sequentially from bottom to top. A liquid-blocking baffle 35 is provided in the gas-liquid separation channel 33, and a channel for gas to pass through is left between the liquid-blocking baffle 35 and the side wall of the gas-liquid separation channel 33.

[0051] The ammonia decomposition microchannel reaction plate provided by this invention integrates preheating, decomposition, gas-liquid separation, and product collection. Ammonia gas, the reactant, is preheated in the preheating chamber 31 and then enters the micro-reaction channel 32. Under the action of a catalyst, it undergoes a decomposition reaction to generate hydrogen and nitrogen. The hydrogen and nitrogen, along with ammonia droplets, enter the gas-liquid separation channel 33. Unreacted ammonia gas condenses into droplets upon encountering a liquid-blocking baffle 35 and flows back into the micro-reaction channel 32 for further decomposition, thus achieving the separation of ammonia and product gases. Hydrogen and nitrogen flow out through a pre-reserved gas channel between the liquid-blocking baffle 35 and the sidewall of the gas-liquid separation channel 33, and finally flow out into the gas collection chamber 34. By combining multiple steps into one unit, the structure is simple, rationally utilizes heat distribution, reduces fluid input power consumption, and improves heat utilization efficiency.

[0052] The preheating chamber 31 is used to preheat the ammonia gas, a reactant, introduced into it. Specifically, preheating can be achieved through a heating device (such as a heating rod and a thermocouple) located on the back of the preheating chamber 31 within the reactor body. This invention does not limit the shape of the preheating chamber 31; as an optional embodiment, the preheating chamber 31 is a rectangular groove. Preferably, the width of the preheating chamber 31 is 30-35 mm, and its length is 10-12 mm.

[0053] Microreaction channel 32 is the site where ammonia decomposition occurs, specifically the reaction: 2NH3=N2+3H2. The inlet of microreaction channel 32 is connected to preheating chamber 31. Preheated ammonia gas enters microreaction channel 32 and undergoes the above reaction to produce hydrogen and nitrogen gas.

[0054] This invention does not limit the number, shape, or catalyst loaded in the microreaction channels 32, and these can be adjusted according to actual needs. As an optional embodiment of this invention, the number of microreaction channels 32 is 5-8, the width of the microreaction channels 32 is 2-4 mm, and the length is 60-65 mm; the microreaction channels 32 are straight tubular microreaction channels; and Ru / La is loaded within the microreaction channels 32. 0.4 Ce 0.6 O 1.8 Catalyst. The use of multiple micro-reaction channels ensures strong gas production even when individual channels become blocked. The temperature for the decomposition reaction is provided by heating devices (such as heating rods and thermocouples) located on the underside of the micro-reaction channels within the reactor body.

[0055] The inlet of the gas-liquid separation channel 33 is connected to the outlet of the micro-reaction channel 32, and the outlet is connected to the gas collection chamber 34. This separation separates the hydrogen and nitrogen generated within the micro-reaction channel 32 from any unreacted ammonia trapped within, allowing the ammonia to fall back into the micro-reaction channel 32 to continue the reaction. During normal operation, no heating device is installed on the back of the gas-liquid separation channel 33, thus creating a temperature difference with the micro-reaction channel 32 area, enhancing the condensation effect of the ammonia and promoting gas-liquid separation.

[0056] The present invention does not limit the number and shape of the gas-liquid separation channels 33 and the shape of the liquid-blocking baffles, and can adjust them according to actual needs.

[0057] As an optional embodiment of the present invention, the liquid-blocking baffle 35 is in the shape of a triangular prism, with one tip of the prism facing the micro-reaction channel 32. This structure enhances the separation capability of ammonia and other gases, allowing unreacted ammonia to flow back, increasing reaction efficiency, and reducing subsequent separation energy consumption.

[0058] As an optional embodiment of the present invention, the gas-liquid separation channel 33 includes an inlet transition section, a straight pipe section, and an outlet section connected sequentially from bottom to top. The inlet transition section is connected to the micro-reaction channel 32 and its width gradually increases from bottom to top. The width of the outlet section is smaller than that of the straight pipe section, and the liquid-blocking baffle 35 is located at the junction of the inlet transition section and the straight pipe section. This structure is more conducive to the outflow of product gas, thereby further promoting ammonia decomposition, accelerating the reaction process, and improving the product gas yield. Preferably, in the gas-liquid separation channel 33, the inlet width of the inlet transition section is 2-4 mm, the outlet width is 4-8 mm, and the length is 10-15 mm; the width of the straight pipe section is 4-8 mm, and the length is 25-30 mm; the width of the outlet section is 2-4 mm, and the length is 5-10 mm; and the width of the liquid-blocking baffle is 2-4 mm.

[0059] The gas collection chamber 34 is connected to the outlet of the gas-liquid separation channel 33 and is used to collect the gaseous products generated by the ammonia decomposition reaction. This invention does not limit the shape of the gas collection chamber 34; as an optional embodiment, the gas collection chamber 34 is a rectangular groove. Preferably, the width of the gas collection chamber 34 is 30-35 mm and the length is 10-12 mm.

[0060] As an optional embodiment of the present invention, the depths of the preheating chamber 31, the micro-reaction channel 32, the gas-liquid separation channel 33, and the gas collection chamber 34 are all 2 mm.

[0061] As an optional embodiment of the present invention, the ammonia decomposition microchannel reaction plate further includes a heating rod and a thermocouple, which are embedded in the reaction plate body and located on the back side of the microchannel structure. For example, heating rod through-holes 36 and thermocouple through-holes 37 for embedding the heating rod and thermocouple can be formed on the reaction plate body. It is understood that during normal operation of the reactor, the heating rod and thermocouple mainly provide heat to the preheating chamber 31 and the micro-reaction channel 32. When the gas-liquid separation channel 33 is blocked, the channel can also be cleared by heating with the heating rod and thermocouple located on its back side. Compared with traditional heat exchange and the use of tail gas combustion to provide heat, electric heating allows the reaction system to start up quickly, and the reaction temperature can be monitored by using a K-type thermocouple in conjunction with a PID controller.

[0062] As an optional embodiment of the present invention, the reaction plate body is made of stainless steel, such as 316L stainless steel.

[0063] like Figures 2-6 As shown, the present invention also provides an ammonia decomposition microchannel reactor, including the aforementioned ammonia decomposition microchannel reaction plate.

[0064] As an optional embodiment of the present invention, the ammonia decomposition microchannel reactor includes a first cover plate 1, a first graphite sheet 2, an ammonia decomposition microchannel reaction plate 3, a second graphite sheet 4, and a second cover plate 5 stacked sequentially. The first graphite sheet 2 and the second graphite sheet 4 seal the front and back sides of the ammonia decomposition microchannel reaction plate 3. The first cover plate 1 has a cover plate outlet, and the first graphite sheet 2 has a graphite sheet outlet 21. Both the cover plate outlet and the graphite sheet outlet 21 are connected to the gas collection chamber 34. The second cover plate 5 has a cover plate inlet, and the second graphite sheet 4 has a graphite sheet inlet 41. Both the cover plate inlet and the graphite sheet inlet 41 are connected to the preheating chamber 31. Specifically, both the cover plate inlet and the graphite sheet inlet 41 are connected to the ammonia inlet 38 opened in the preheating chamber 31.

[0065] The reactor has a compact structure, making it suitable for small-flow hydrogen production applications. It is assembled in a stacked manner, which facilitates easy disassembly, assembly, and catalyst loading. It is highly modular, allowing for increased reaction scale through stacked reaction plates. Its simple structure and low cost, along with precise temperature control, result in a small temperature gradient within the reactor, providing an excellent reaction environment for the catalyst and effectively improving the reactor's heat and mass transfer performance and reaction efficiency.

[0066] The first cover plate 1 and the second cover plate 5 are used to encapsulate the reaction plate. The present invention does not limit their shape, size and material.

[0067] As an optional embodiment of the present invention, both the first cover plate 1 and the second cover plate 5 are stainless steel plates. The first cover plate 1 and the second cover plate 5 are connected by bolts. Specifically, the first cover plate 1 has a first cover plate bolt mounting hole 11, and the second cover plate 5 has a first cover plate bolt mounting hole 51. Bolts pass through the first cover plate bolt mounting holes 11 and 51 and are fastened by nuts.

[0068] As an optional embodiment of the present invention, the thickness of the first cover plate 1 and the second cover plate 5 is 5 mm.

[0069] As an optional embodiment of the present invention, a gas outlet pipe 12 is connected to the first cover plate 1, and the gas outlet pipe 12 is connected to the outlet of the cover plate. A feed pipe 52 is connected to the second cover plate 5, and the feed pipe 52 is connected to the inlet of the cover plate. The feed pipe 52 is used to introduce the ammonia gas, the raw material for reaction, into the preheating chamber 31, and the gas outlet pipe 12 is used to discharge the gaseous products in the gas collection chamber 34.

[0070] The first graphite sheet 2 and the second graphite sheet 4 serve to insulate the reaction plate. This invention does not limit its shape or size, as long as it can seal both sides of the ammonia decomposition microchannel reaction plate 3.

[0071] As an optional embodiment of the present invention, the thickness of the first graphite sheet 2 and the second graphite sheet 4 is 2 mm.

[0072] This invention does not limit the connection method between the components. As an optional embodiment, the first cover plate 1 has a first cover plate positioning hole 13, the first graphite sheet 2 has a first graphite sheet positioning hole 22, the ammonia decomposition microchannel reaction plate 3 has a reaction plate positioning hole 39, the second graphite sheet 4 has a second graphite sheet positioning hole 42, and the second cover plate 5 has a second cover plate positioning hole 53. The first cover plate positioning hole 13, the first graphite sheet positioning hole 22, the reaction plate positioning hole 39, the second graphite sheet positioning hole 42, and the second cover plate positioning hole 53 are interconnected. The positioning holes on each component facilitate installation and positioning.

[0073] Detailed Implementation Plan

[0074] The technical solution of the present invention will be further described below with reference to a specific embodiment.

[0075] Example 1

[0076] like Figures 1-6 As shown, this embodiment provides an ammonia decomposition microchannel reactor, which consists of a first cover plate 1, a first graphite sheet 2, an ammonia decomposition microchannel reaction plate 3, a second graphite sheet 4, and a second cover plate 5 stacked sequentially from front to back.

[0077] The ammonia decomposition microchannel reaction plate 3 consists of a reaction plate body and a microchannel structure formed on the reaction plate body. The microchannel structure comprises a preheating chamber 31, a microreaction channel 32, a gas-liquid separation channel 33, and a gas collection chamber 34 connected sequentially from bottom to top. The preheating chamber 31 and the gas collection chamber 34 are rectangular grooves. An ammonia inlet 38 is provided in the preheating chamber 31. The microreaction channel 32 is a straight-tube type microreaction channel, and Ru / La is loaded within the microreaction channel 32. 0.4 Ce 0.6 O 1.8 Catalyst; A liquid-blocking baffle 35 is provided in the gas-liquid separation channel 33, and a channel for gas to pass through is left between the liquid-blocking baffle 35 and the side wall of the gas-liquid separation channel 33. The liquid-blocking baffle 35 is triangular prism-shaped, and one tip of the triangular prism faces the micro-reaction channel 32. The gas-liquid separation channel 33 is composed of an inlet transition section, a straight pipe section and an outlet section connected sequentially from bottom to top. The inlet transition section is connected to the micro-reaction channel 32 and its width gradually increases from bottom to top. The width of the outlet section is smaller than that of the straight pipe section. The liquid-blocking baffle 35 is located at the junction of the inlet transition section and the straight pipe section. Heating rod through holes 36 and thermocouple through holes 37 for embedding heating rods and thermocouples are respectively opened on the back of the preheating chamber 31, the micro-reaction channel 32, the gas-liquid separation channel 33 and the gas collection chamber 34 on the reaction plate body.

[0078] The ammonia decomposition microchannel reaction plate 3 measures 40mm × 140mm and is 10mm thick; it is made of 316L stainless steel. The preheating chamber 31 has a width of 32mm and a length of 10mm. The gas collection chamber 34 has a width of 32mm and a length of 10mm. There are 5 micro-reaction channels 32 and 5 gas-liquid separation channels 33. The micro-reaction channel 32 has a width of 2mm and a length of 60mm. In the gas-liquid separation channel 33, the inlet transition section has an inlet width of 2mm, an outlet width of 4mm, and a length of 15mm. The straight pipe section has a width of 4mm and a length of 25mm. The outlet section has a width of 2mm and a length of 5mm. The liquid-blocking baffle 35 has a width of 2mm. The preheating chamber 31, the micro-reaction channel 32, the gas-liquid separation channel 33, and the gas collection chamber 34 all have a depth of 2mm. There are 4 heating rod through holes 36 with a diameter of 6mm. There are 4 thermocouple through holes 37 with a diameter of 1.2mm.

[0079] The first graphite sheet 2 and the second graphite sheet 4 seal the front and back of the ammonia decomposition microchannel reaction plate 3. The first cover plate 1 has a cover plate outlet, and the first graphite sheet 2 has a graphite sheet outlet 21. Both the cover plate outlet and the graphite sheet outlet 21 are connected to the gas collection chamber 34. The second cover plate 2 has a cover plate inlet 21, and the second graphite sheet 4 has a graphite sheet inlet 41. Both the cover plate inlet 21 and the graphite sheet inlet 41 are connected to the ammonia inlet 38 in the preheating chamber 31. The first cover plate 1 is connected to the gas outlet pipe 12, which is connected to the cover plate outlet. The second cover plate 5 is connected to the feed pipe 52, which is connected to the cover plate inlet.

[0080] The dimensions of the first cover plate 1 and the second cover plate 5 are 50mm × 150mm and the thickness is 5mm; the material is stainless steel plate; the air outlet pipe 12 and the feed pipe 52 are also stainless steel pipes; the first cover plate 1 has a first cover plate bolt mounting hole 11 and the second cover plate 5 has a first cover plate bolt mounting hole 51. The bolt passes through the first cover plate bolt mounting hole 11 and the first cover plate bolt mounting hole 51 and is fastened by a nut.

[0081] The dimensions of the first graphite sheet 2 and the second graphite sheet 4 are 35mm × 130mm, and the thickness is 2mm.

[0082] The first cover plate 1 has a first cover plate positioning hole 13, the first graphite sheet 2 has a first graphite sheet positioning hole 22, the ammonia decomposition microchannel reaction plate 3 has a reaction plate positioning hole 39, the second graphite sheet 4 has a second graphite sheet positioning hole 42, and the second cover plate 5 has a second cover plate positioning hole 53. The first cover plate positioning hole 13, the first graphite sheet positioning hole 22, the reaction plate positioning hole 39, the second graphite sheet positioning hole 42, and the second cover plate positioning hole 53 are interconnected.

[0083] This embodiment also provides a method for producing hydrogen from ammonia by using the aforementioned ammonia decomposition microchannel reactor. Specifically, ammonia gas is added to the preheating chamber 31 through the feed pipe 52, and the product gas is discharged from the gas collection chamber 34 through the outlet pipe 12.

[0084] Experimental Example 1

[0085] Airspeed is 12000 h -1 Under the operating conditions, the ammonia decomposition microchannel reactor provided in Example 1 was used at different reaction temperatures and different Ru / La ratios. x Ce x-1 O y The experiment was conducted under the specified mixing conditions.

[0086] The ammonia decomposition products H2 and N2 were collected using a water displacement method. The flow rate of the generated gas was measured over time, which is the ammonia decomposition flow rate, and the ammonia conversion rate was calculated accordingly. Since ammonia is highly soluble in water, phenolphthalein solution was added to the wastewater to prevent undecomposed ammonia from dissolving in the water, ensuring no ammonia dissolved in the water. This also demonstrates that the microchannel reactor has a good ability to separate ammonia and its products.

[0087] from Figure 7 It can be seen that as the reaction temperature increases, the ammonia conversion rate increases because the ammonia decomposition reaction is endothermic. Furthermore, when the reaction temperature exceeds 450℃, the Ru / La... 0.4 Ce 0.6 O 1.8 The catalyst achieved the highest NH3 conversion. The order of NH3 conversion is as follows: Ru / La 0.4 Ce 0.6 O 1.8 >Ru / La 0.5 Ce 0.5 O 1.75 >Ru / La 0.3 Ce 0.7 O 1.85 >Ru / La 0.1 Ce 0.9 O 1.95 ≈Ru / CeO2. When the reaction temperature is 450℃ and the space velocity is 12000 h⁻¹. -1 Under these conditions, the present invention uses Ru / La 0.4 Ce 0.6 O 1.8 It can provide a high ammonia conversion rate of 98.81%.

[0088] Experimental Example 2

[0089] Using Ru / La 0.4 Ce 0.6 O 1.8 Catalyst, at 450℃ and space velocity 12000h -1 Under the conditions described in Example 1, experiments were conducted using the ammonia decomposition microchannel reactor. From... Figure 8 As can be seen, the ammonia conversion rate remains above 97% with increasing reaction time. That is, at a reaction temperature of 450℃ and a space velocity of 12000 h⁻¹, this conversion rate is maintained. -1 Under the conditions described in Example 1, the ammonia decomposition microchannel reactor used Ru / La 0.4 Ce 0.6 O 1.8 It can run stably for more than 45 hours.

[0090] Experimental Example 3

[0091] Using Ru / La0.4 Ce 0.6 O 1.8 The catalyst was tested using the ammonia decomposition microchannel reactor provided in Example 1 under different reaction temperatures and space velocities. Figure 9 As can be seen, with decreasing space velocity, at the same temperature, the ammonia conversion rate increases due to the longer residence time. Furthermore, when the reaction temperature increases, excessively low space velocities can cause catalyst deactivation due to coking. Therefore, when the reaction temperature is 400℃ and the space velocity is 1000 h⁻¹, the reaction is less efficient. -1 Under the conditions described in Example 1, the ammonia decomposition microchannel reactor used Ru / La 0.4 Ce 0.6 O 1.8 It can provide a sustained and stable ammonia conversion rate of 76%.

[0092] Experiment Example 4

[0093] Using Ru / La 0.4 Ce 0.6 O 1.8 Catalyst, at 400℃ and space velocity of 1000h -1 Experiments were conducted using the ammonia decomposition microchannel reactor provided in Example 1 and other microchannel reactors under the specified conditions. These other microchannel reactors included a standard straight-through microchannel reactor (without diameter variation, other conditions the same as in Example 1) and an ammonia decomposition microchannel reactor based on Example 1 with the liquid-blocking baffle removed. Figure 10 As can be seen, the variable reactor diameter facilitates the decomposition of ammonia into nitrogen and hydrogen. The ammonia decomposition microchannel reactor used in Example 1 of this invention can improve ammonia conversion efficiency by 20% compared to a conventional straight-through microchannel reactor.

[0094] 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. An ammonia decomposition microchannel reaction plate characterized by, The microchannel reaction plate comprises a reaction plate body and a microchannel structure formed on the reaction plate body, the microchannel structure comprises, from bottom to top, a preheating chamber, a micro-reaction channel, a gas-liquid separation channel and a gas collection chamber, a liquid-blocking baffle is arranged in the gas-liquid separation channel, a passage for gas passing through is left between the liquid-blocking baffle and the sidewall of the gas-liquid separation channel, the micro-reaction channel is a straight pipe type micro-reaction channel, the liquid-blocking baffle is in the shape of a triangular prism, and a pointed end of the triangular prism faces the micro-reaction channel, the gas-liquid separation channel comprises, from bottom to top, an inlet transition section, a straight pipe section and an outlet section, the inlet transition section is connected with the micro-reaction channel, and the width of the inlet transition section gradually increases from bottom to top, the width of the outlet section is smaller than that of the straight pipe section, and the liquid-blocking baffle is located at the joint of the inlet transition section and the straight pipe section.

2. The ammonia decomposition microchannel reaction plate according to claim 1, wherein the preheating chamber and the gas collection chamber are in the shape of rectangular grooves, the width of the preheating chamber is 30-35 mm, and the length thereof is 10-12 mm, the width of the gas collection chamber is 30-35 mm, and the length thereof is 10-12 mm; the width of the micro-reaction channel is 2-4 mm, and the length thereof is 60-65 mm; in the gas-liquid separation channel, the width of the inlet of the inlet transition section is 2-4 mm, the width of the outlet thereof is 4-8 mm, and the length thereof is 10-15 mm, the width of the straight pipe section is 4-8 mm, and the length thereof is 25-30 mm, the width of the outlet section is 2-4 mm, and the length thereof is 5-10 mm, and the width of the liquid-blocking baffle is 2-4 mm; the number of the micro-reaction channels and the gas-liquid separation channels is 5-8; the depth of the preheating chamber, the micro-reaction channel, the gas-liquid separation channel and the gas collection chamber is 2 mm; the material of the reaction plate body is stainless steel; the micro-reaction channel is a straight pipe type micro-reaction channel; The micro-reaction channel is loaded with Ru / La 0.4 Ce 0.6 O 1.8 catalyst.

3. The ammonia decomposition microchannel reaction plate of claim 1, wherein, further comprising a heating rod and a thermocouple, which are embedded in the reaction plate body and located at the back of the microchannel structure.

4. An ammonia decomposition microchannel reactor characterized by, The ammonia decomposition microchannel reaction plate according to any one of claims 1-3.

5. The ammonia decomposition microchannel reactor of claim 4, wherein, The ammonia decomposition microchannel reaction plate according to any one of claims 1-3. The ammonia decomposition microchannel reaction plate according to any one of claims 1-3.

6. The ammonia decomposition microchannel reaction plate according to claim 5, wherein the first cover plate and the second cover plate are both stainless steel plates; the first cover plate and the second cover plate are connected by bolts; the thickness of the first cover plate and the second cover plate is 5 mm; the thickness of the first graphite sheet and the second graphite sheet is 2 mm.

7. A method for hydrogen production by ammonia decomposition, characterized by, The use of the ammonia decomposition microchannel reactor according to any one of claims 4 to 6 is carried out.

8. The ammonia decomposition hydrogen production method according to claim 7, characterized by, The reaction temperature is 300-400°C, and the space velocity is 1500-10000 h -1 .

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