A process for preparing solid magnesium hydride from cracked crushed metal magnesium

Abstract

The present invention provides a process for preparing solid magnesium hydride from cracked, crushed metal magnesium, which relates to the technical field of magnesium hydride preparation and solves the technical problem in the prior art of preparing magnesium hydride by directly reacting magnesium bars with hydrogen, but the energy consumption and preparation cost of the preparation process are relatively high. The device has the following operating steps: cutting a block metal ingot into crushed metal chips; subjecting the metal chips to an initial extrusion operation to produce cracks on the surface of the metal chips after extrusion; placing the metal chips into a reaction device and introducing hydrogen for reaction. Compared with conventional gaseous hydrogen storage, the bottled magnesium hydride prepared by the process of the present invention has ten times the hydrogen storage capacity at the same volume; and because the storage is at room temperature and pressure, the long-distance transportation and long-term storage (more than 5 years) of hydrogen are safely achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium hydride preparation, in particular to a process for preparing solid magnesium hydride from cracked crushed metallic magnesium. Background Art

[0002] Hydrogen is used in many industrial sectors, particularly as a fuel (e.g., in heat engines or fuel cells) or as a reagent (e.g., in hydrogenation reactions). Within this context, given the volume of gaseous hydrogen and its explosive properties, it is desirable to store hydrogen in a small volume in safe containers.

[0003] One method of storing hydrogen is through the use of metal hydrides, namely magnesium hydride (MgH2). Metal hydrides are not only easy to use and safe, as they do not require the specialized conditions of ultra-high pressure and extremely low temperature to store hydrogen, but also offer a high hydrogen storage capacity per unit volume.

[0004] Currently, magnesium hydride is usually prepared by directly reacting magnesium rods with hydrogen in the prior art. However, the energy consumption in this preparation process is relatively high, and the preparation cost is also relatively high. Summary of the Invention

[0005] The present invention aims to provide a process for preparing solid magnesium hydride from cracked, crushed magnesium metal. This process addresses the existing technical issues of producing magnesium hydride by directly reacting magnesium bars with hydrogen, which results in high energy consumption and production costs. The various technical effects achieved by the preferred technical solutions provided by the present invention are detailed below.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metallic magnesium, comprising the following steps:

[0008] Step S1: Cutting a bulk metal ingot into crushed metal chips;

[0009] Step S2: performing a primary extrusion operation on the metal chips to generate cracks on the surface of the metal chips after extrusion;

[0010] Step S3: placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction.

[0011] Optionally, the step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes:

[0012] Step S31: first, the extruded metal chips are loaded into a material frame;

[0013] Step S32: placing the material frame containing the metal chips into the reaction device, and introducing hydrogen to carry out the reaction.

[0014] Optionally, the step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes:

[0015] Step S3a: pressing the extruded metal chips to form granular metal particles;

[0016] Step S3b: placing the metal particles into the reaction device and introducing hydrogen to carry out the reaction.

[0017] Optionally, in step S3b, an inner cylinder is provided in the reaction device, the inner cylinder is made of a flexible expansion constraint net, the metal particles are placed in the inner cylinder, and an expansion gap exists between the inner cylinder and the outer wall of the reaction device.

[0018] Optionally, the inner cylinder is made of titanium metal.

[0019] Optionally, the step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes:

[0020] Step S3A: Filling the extruded metal chips into a woven mesh bag and compacting it, and then sealing the filling port of the woven mesh bag;

[0021] Step S3B: performing an oscillating operation on the woven mesh bag containing the metal chips;

[0022] Step S3C: rolling or pressing the woven mesh bag containing the metal chips to form a metal plate with a plate-like structure or processing it into a shape matching the reaction device;

[0023] Step S3D: Wrapping the metal plate around the heating structure in the reaction device, and introducing hydrogen to carry out the reaction.

[0024] Optionally, the material used for the woven mesh bag is a metal catalyst.

[0025] Optionally, the reaction device includes a reaction shell, a heating structure, a heat exchange system, a temperature detection system, a pressure detection system, a gas pipeline system and a control system. At least one columnar heating structure is installed inside the reaction shell. The heat exchange system, the temperature detection system, the pressure detection system and the gas pipeline system are all installed on the reaction shell. The heating structure, the heat exchange system, the temperature detection system, the pressure detection system and the gas pipeline system are all connected to the control system. The control system can control the operation of the heating structure and the heat exchange system. The temperature detection system can detect the temperature of the heating structure and the heat exchange system in real time and transmit the detected temperature information to the control system. The pressure detection system can detect the pressure inside the reaction shell in real time and transmit the detected pressure information to the control system.

[0026] Optionally, the gas pipeline system includes a high-temperature resistant pipeline, a pressure relief device, an oxygen content sensor, a gas flow meter, a vacuum device, a valve body, a pipeline cooling device, a pipeline temperature sensor and a filtering device.

[0027] Optionally, in step S1, the block metal ingot is cut into the crushed metal chips using a stepping cutting tool, and the stepping of the stepping cutting tool is less than or equal to 0.2 mm.

[0028] The present invention provides a process for preparing solid magnesium hydride from cracked, crushed metallic magnesium. The process comprises cutting a block metal ingot (i.e., metallic magnesium) into crushed metal chips (magnesium chips), then subjecting the metal chips to a primary extrusion operation, wherein the extrusion force applied to the metal chips is greater than the ultimate stress of the metal chips, so that cracks are generated on the surface of the extruded metal chips. The cracks greatly increase the surface area of ​​the magnesium chips, effectively increasing the amount of reaction participation per unit time when reacting with hydrogen, and simultaneously destroying the oxide layer attached to the magnesium surface. The metal chips are then placed in a reaction device, and hydrogen is introduced for reaction. The oxide layer on the magnesium surface does not need to be broken at high temperature, and the reaction temperature is uniform throughout the entire process, below the ignition point of hydrogen, thereby achieving safety and energy conservation. In addition, due to the cracks on the magnesium surface, the reaction contact area between the magnesium and hydrogen is greatly increased, and the total reaction time can be significantly reduced. This solves the technical problem in the prior art of preparing magnesium hydride by directly reacting magnesium bars with hydrogen, which results in high energy consumption and high production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a flow chart of Example 1 of a process for preparing solid magnesium hydride from cracked crushed magnesium metal provided by an embodiment of the present invention;

[0031] Figure 2 This is a flow chart of Example 2 of a process for preparing solid magnesium hydride from cracked crushed magnesium metal provided by an embodiment of the present invention;

[0032] Figure 3 This is a flow chart of Example 3 of a process for preparing solid magnesium hydride from cracked crushed magnesium metal provided by an embodiment of the present invention;

[0033] Figure 4 This is a microscopic image of magnesium chips before initial extrusion in a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0034] Figure 5 This is a microscopic image of magnesium chips after initial extrusion in a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0035] Figure 6 This is a schematic structural diagram of a reaction device according to Example 1 of a process for preparing solid magnesium hydride from cracked crushed metallic magnesium provided by an embodiment of the present invention;

[0036] Figure 7 This is a schematic structural diagram of a reaction device according to Example 2 of a process for preparing solid magnesium hydride from cracked crushed metallic magnesium provided by an embodiment of the present invention;

[0037] Figure 8 This is a schematic structural diagram of an inner cylinder of Example 2 of a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0038] Figure 9 This is a cross-sectional view of the inner cylinder of Example 2 of a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0039] Figure 10 This is a schematic structural diagram of a reaction device according to Example 3 of a process for preparing solid magnesium hydride from cracked crushed metallic magnesium provided by an embodiment of the present invention;

[0040] Figure 11 yes Figure 10 Cross-section of the middle AA;

[0041] Figure 12 This is a schematic structural diagram of a woven mesh bag filled with magnesium chips before pressing, according to Example 3 of a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0042] Figure 13 This is a cross-sectional view of a woven mesh bag filled with magnesium chips before pressing, according to Example 3 of a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention;

[0043] Figure 14 This is a cross-sectional view of a woven mesh bag filled with magnesium chips after pressing, according to Example 3 of a process for preparing solid magnesium hydride from cracked crushed metal magnesium provided by an embodiment of the present invention.

[0044] In the figure, 1 is a reaction device; 11 is an inner cylinder; 12 is a heating structure; 13 is a reaction shell;

[0045] 2. Material frame;

[0046] 3. Magnesium board;

[0047] 4. Woven mesh bag;

[0048] 5. Magnesium chips;

[0049] 6. Magnesium;

[0050] 7. Oxide layer. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. 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 implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be noted that, unless otherwise specified, the term "plurality" means two or more. Terms such as "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "head," and "tail" are used to indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention depending on the specific circumstances.

[0054] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metallic magnesium, comprising the following steps:

[0055] Step S1: Cutting a bulk metal ingot into crushed metal chips;

[0056] Step S2: The metal chips are subjected to a primary extrusion operation to produce cracks on the surface of the extruded metal chips. The chip cutting operation and the primary extrusion operation of the metal chips can be carried out in a natural aerobic environment. There is no need to worry about the subsequent formation of a surface oxide layer. Since the metal chips will break before the pure metal part during the pressure extrusion process, and the cracks are more dense (the oxide layer is an important factor that hinders the hydrogenation reaction), the processing technology in an aerobic environment is simpler and faster. Figure 4 This is a microscopic image of magnesium chips before the initial extrusion, where the magnesium elements 6 are connected together; see Figure 5 This is a microscopic picture of magnesium chips after the initial extrusion. Some of the magnesium elements 6 are disconnected and cracked, and the oxide layer on the surface of the magnesium chips is also broken.

[0057] Step S3: placing metal chips into the reaction device 1 and introducing hydrogen to carry out the reaction. The present invention provides a process for preparing solid magnesium hydride from cracked, crushed magnesium metal. The process comprises cutting a bulk metal ingot (i.e., magnesium metal) into crushed metal chips (magnesium chips 5), then subjecting the metal chips to a primary extrusion operation, wherein the extrusion force applied to the metal chips is greater than the ultimate stress of the metal chips, so that cracks are generated on the surface of the extruded metal chips. The cracks greatly increase the surface area of ​​the magnesium chips 5, effectively increasing the amount of reaction participation per unit time when reacting with hydrogen, and simultaneously destroying the oxide layer attached to the magnesium surface. The metal chips are then placed in a reaction device 1, and hydrogen is introduced for reaction. The oxide layer on the magnesium surface does not need to be broken at high temperature, and the reaction temperature is uniform throughout the entire process, below the ignition point of hydrogen, thereby achieving safety and energy conservation. In addition, due to the cracks on the magnesium surface, the reaction contact area between the magnesium and hydrogen is greatly increased, and the total reaction time can also be significantly reduced. This solves the technical problem of high energy consumption and high production cost in the prior art of preparing magnesium hydride by directly reacting magnesium bars with hydrogen.

[0058] Example 1:

[0059] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metallic magnesium, comprising the following steps:

[0060] Step S1: Cutting the bulk magnesium ingot into crushed magnesium chips 5, specifically using a stepping cutting tool to cut the bulk magnesium ingot into crushed magnesium chips 5. To ensure the stability of mass production, the stepping cutting tool has a stepping distance of less than or equal to 0.2 mm, and the cross-section of the formed magnesium chips 5 can be circular, square, diamond-shaped, or other irregular shapes. Preferably, the magnesium chips 5 can be prepared by fast rotating cutting with a flat drill bit, which greatly reduces the cutting cost of the magnesium chips 5. The bit should be able to achieve a stepping coefficient of 0.1 mm. In theory, the lower the feed rate, the closer the state of the processed magnesium chips 5, and the more convenient the overall control, but this will increase the cost accordingly.

[0061] Step S2: The magnesium chips 5 are subjected to an initial extrusion operation, wherein the extrusion force applied to the magnesium chips 5 is greater than the ultimate stress of the magnesium chips 5, so that cracks are generated on the surface of the extruded magnesium chips 5. Specifically, due to the poor ductility of magnesium, the stress generated by the extrusion causes it to deform and crack. That is, the extrusion force is greater than its ultimate stress. The cracks will greatly increase the surface area of ​​the magnesium chips 5, thereby effectively increasing the amount of reaction per unit time when reacting with hydrogen, and at the same time, destroying the oxide layer attached to the magnesium surface. The magnesium chips 5 can be extruded using hydraulic equipment;

[0062] Step S31: first, the extruded magnesium chips 5 are loaded into the material frame 2, and the material used is titanium metal;

[0063] Step S32: placing the material frame 2 containing the magnesium chips 5 into the reaction device 1 and introducing hydrogen to carry out the reaction.

[0064] Example 2:

[0065] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metallic magnesium, comprising the following steps:

[0066] Step S1: Cutting the bulk magnesium ingot into crushed magnesium chips 5, specifically using a stepping cutting tool to cut the bulk magnesium ingot into crushed magnesium chips 5. To ensure the stability of mass production, the stepping cutting tool has a stepping distance of less than or equal to 0.2 mm, and the cross-section of the formed magnesium chips 5 can be circular, square, diamond-shaped, or other irregular shapes. Preferably, the magnesium chips 5 can be prepared by fast rotating cutting with a flat drill bit, which greatly reduces the cutting cost of the magnesium chips 5. The bit should be able to achieve a stepping coefficient of 0.1 mm. In theory, the lower the feed rate, the closer the state of the processed magnesium chips 5, and the more convenient the overall control, but this will increase the cost accordingly.

[0067] Step S2: The magnesium chips 5 are subjected to an initial extrusion operation, wherein the extrusion force applied to the magnesium chips 5 is greater than the ultimate stress of the magnesium chips 5, so that cracks are generated on the surface of the extruded magnesium chips 5. Specifically, due to the poor ductility of magnesium, the stress generated by the extrusion causes it to deform and crack. That is, the extrusion force is greater than its ultimate stress. The cracks will greatly increase the surface area of ​​the magnesium chips 5, thereby effectively increasing the amount of reaction per unit time when reacting with hydrogen, and at the same time, destroying the oxide layer attached to the magnesium surface. The magnesium chips 5 can be extruded using hydraulic equipment;

[0068] Step S3a: The extruded magnesium chips 5 are pressed to form granular magnesium particles. Specifically, the extruded magnesium chips 5 are placed in a mold for a second pressing operation. The pressure of this pressing is relatively small, so that the magnesium chips 5 are aggregated into block particles. This helps to increase the volume hydrogen storage ratio of the reactant solid block magnesium hydride and is more convenient for removal and transfer. When the second-pressed magnesium particles are subjected to pressure again in a cracked state, their lattices can undergo a second deformation, and the direction of the deformation is likely to be inconsistent with the first deformation direction. The gaps between the lattices are more conducive to the entry of hydrogen, thereby accelerating the reaction.

[0069] Step S3b: Magnesium particles are placed in the reaction device 1. The reaction device 1 is provided with an inner cylinder 11, which is made of a flexible expansion constraint mesh. The magnesium particles are placed in the inner cylinder 11. There is an expansion gap between the inner cylinder 11 and the outer wall of the reaction device 1 (reactor), and hydrogen is introduced to react.

[0070] Preferably, due to the expansion characteristics of magnesium granules when converted into magnesium hydride, the magnesium chips 5 after secondary pressing slowly release their elastic potential energy when reacting with hydrogen. Therefore, a certain structure is required within the reactor to absorb this potential energy. Specifically, an inner cylinder 11 with a flexible, anti-expansion structure is designed inside the reactor. When the magnesium granules are canned into the reactor, they are confined within the inner cylinder 11. An expansion gap is left between the inner cylinder 11 and the inner wall of the reactor. When the magnesium granules absorb hydrogen and expand, the force of the expansion of the magnesium granules is evenly distributed in all directions by the inner cylinder 11 until it abuts the inner wall of the reactor.

[0071] The flexible, anti-expansion structure of the inner cylinder 11 not only prevents magnesium particles from agglomerating at the bottom of the reactor 1, impacting the reaction, but also eliminates the risk of excessive pressure on the bottom of the reactor due to particle expansion. The gap between the inner cylinder 11 and the inner wall of the reactor ensures hydrogen transport. Contact between the inner cylinder 11 and the inner wall of the reactor facilitates heat transfer, shortens reaction time, and improves reaction efficiency. The inner cylinder 11 improves the efficiency and safety of subsequent recovery of solid hydrogen storage materials.

[0072] The material of the inner cylinder 11 can be titanium. On the one hand, titanium has strong toughness and can bear the elastic potential energy released by crushing the magnesium chips 5. On the other hand, the titanium in the reactor can accelerate the process of decomposing hydrogen molecules into hydrogen atoms at a temperature of 300-400°C.

[0073] The crushed magnesium particles concentrated in the center of the reactor are more concentrated in the early stage of the reaction. Coupled with their nature of absorbing hydrogen and releasing heat, their reaction energy consumption will be reduced to a certain extent. After expanding in the later stage, their excess heat can flow quickly to unreacted areas along with hydrogen through their loose structure, which can prevent the reverse reaction of magnesium hydride (under the same pressure, as the temperature increases, magnesium and hydrogen go from combination to decomposition).

[0074] Example 3:

[0075] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metallic magnesium, comprising the following steps:

[0076] Step S1: Cutting the bulk magnesium ingot into crushed magnesium chips 5, specifically using a stepping cutting tool to cut the bulk magnesium ingot into crushed magnesium chips 5. To ensure the stability of mass production, the stepping cutting tool has a stepping distance of less than or equal to 0.2 mm, and the cross-section of the formed magnesium chips 5 can be circular, square, diamond-shaped, or other irregular shapes. Preferably, the magnesium chips 5 can be prepared by fast rotating cutting with a flat drill bit, which greatly reduces the cutting cost of the magnesium chips 5. The bit should be able to achieve a stepping coefficient of 0.1 mm. In theory, the lower the feed rate, the closer the state of the processed magnesium chips 5, and the more convenient the overall control, but this will increase the cost accordingly.

[0077] Step S2: The magnesium chips 5 are subjected to an initial extrusion operation, wherein the extrusion force applied to the magnesium chips 5 is greater than the ultimate stress of the magnesium chips 5, so that cracks are generated on the surface of the extruded magnesium chips 5. Specifically, due to the poor ductility of magnesium, the stress generated by the extrusion causes it to deform and crack. That is, the extrusion force is greater than its ultimate stress. The cracks will greatly increase the surface area of ​​the magnesium chips 5, thereby effectively increasing the amount of reaction per unit time when reacting with hydrogen, and at the same time, destroying the oxide layer attached to the magnesium surface. The magnesium chips 5 can be extruded using hydraulic equipment;

[0078] Step S3A: Filling the extruded magnesium chips 5 into the woven mesh bag 4 and filling it tightly, and then sealing the filling port of the woven mesh bag 4;

[0079] Step S3B: Oscillating the woven mesh bag 4 containing the magnesium chips 5 to ensure that there is no magnesium powder or fine particles generated during the cutting and pressing process. The oscillation process can be performed in an inert environment to reduce the probability of safety hazards.

[0080] Step S3C: The woven mesh bag 4 containing the magnesium chips 5 is rolled or pressed to form a magnesium plate 3 with a plate-like structure or to be processed into a shape that matches the reaction device 1. The rolling or pressing operation should ensure that the integrity of the woven mesh bag 4 is not damaged and that the magnesium chips 5 do not leak out. The woven mesh bag 4 has better plasticity than magnesium and is not easily damaged. If it is prepared by rolling, the formed magnesium plate 3 has strong elasticity and plasticity. The pressed magnesium plate 3 has a small space and is convenient for transportation or filling, or it can be further extruded to match the shape of the subsequent reaction device 1. The magnesium chips 5 wrapped in the woven mesh bag 4 can also be molded into other shapes that are conducive to the reaction, such as a sandwich mode that matches a pancake device or a square device.

[0081] Step S3D: Wrap the magnesium plate 3 on the heating structure 12 in the reaction device 1 and introduce hydrogen to carry out the reaction.

[0082] As an optional embodiment, the material used for the woven mesh bag 4 is a metal catalyst, specifically titanium, nickel, vanadium and other metal materials. The woven mesh bag 4 serves as a catalyst for the hydrogen-magnesium reaction, which helps hydrogen decompose into hydrogen atoms and accelerate the reaction with magnesium.

[0083] As an optional embodiment, the reaction device 1 includes a reaction shell 13, a heating structure 12, a heat exchange system, a temperature detection system, a pressure detection system, a gas pipeline system and a control system. The outer surface of the reaction shell 13 can be coated with an insulation coating to further prevent heat loss. At least one cylindrical heating structure 12 is installed inside the reaction shell 13, and the magnesium plate 3 is wrapped around the entire heating structure 12 to achieve central heating, and heat is diffused and absorbed by the surrounding magnesium chips 5 to maximize the utilization of thermal energy; the heat exchange system, temperature detection system, pressure detection system and gas pipeline system are all installed on the reaction shell 13, and the heating structure 12, heat exchange system, temperature detection system, pressure detection system and gas pipeline system are all connected to the control system. The control system can control the operation of the heating structure 12 and the heat exchange system. The temperature detection system can detect the temperature on the heating structure 12 and the heat exchange system in real time and transmit the detected temperature information to the control system. The temperature detection system can determine the temperature change trend and respond to the control system in a timely manner. The control system turns on or off the heating structure 12 and the heat exchange system according to the temperature change trend. The pressure detection system can detect the pressure inside the reaction shell 13 in real time and transmit the detected pressure information to the control system. The pressure detection device ensures that the minimum required pressure for the hydrogenation of solid magnesium blocks is 6 bar. Increasing the pressure can correspondingly increase the reaction temperature. The higher the temperature, the faster the reaction and the shorter the total time. The overall energy consumption depends on the pressure, temperature, and the structure of the reaction device 1.

[0084] The reaction shell 13 is made of 316L stainless steel, and can also be made of other high temperature and high pressure resistant materials suitable for hydrogen. The pressure inside the reaction shell 13 should meet the working pressure of 3MPa and the temperature resistance should meet the long-term working temperature of 500℃;

[0085] The heating structure 12 needs to have a certain structural strength to support the magnesium plate 3 without deformation that affects its function. The heating structure 12 is provided with a temperature-controllable heating wire. The opening and closing time and power of the heating wire are controlled by the control system and the temperature detection system. The temperature control range is ±10°C.

[0086] The magnesium plate 3 can be wrapped around the heating structure 12 in a spiral shape, allowing hydrogen to easily penetrate the interior through the gaps. Furthermore, gaps exist between the magnesium chips 5, allowing hydrogen to penetrate. Furthermore, the spiral structure absorbs the expansion coefficient of magnesium transformed into magnesium hydride, as well as the expansion coefficient of the pressed magnesium plate 3 after repeated hydrogen absorption and desorption. Simultaneously, the expanded magnesium plate 3 can gradually diffuse throughout the entire space of the reaction shell 13, further improving thermal energy utilization (forming a honeycomb-like space). The woven mesh bag 4 effectively prevents the magnesium or magnesium hydride from falling out during the reaction; otherwise, uncontrolled release of material could lead to failure of the gas pipeline system.

[0087] The heating device ensures that the minimum required temperature for the hydrogenation of solid magnesium is 340°C. Increasing the temperature can increase the activity of magnesium and hydrogen and reduce the reaction time. However, correspondingly, higher temperatures will also lead to higher energy consumption and increase safety risks as it is close to the ignition point of hydrogen. In order to eliminate the interference of the instability of the heating device and ensure the continuity of the reaction, the ideal temperature should be 350-370°C, which can ensure the normal reaction while reducing energy waste.

[0088] The heating device does not need to stabilize the temperature of the entire device. As long as its own temperature reaches the specified temperature, its heat can effectively make the solid magnesium reach the reaction temperature. All heat will be transferred through the coated magnesium, making fuller use of heat energy. This mode is easier to control, and there is no need to worry about higher energy consumption strategies due to uneven heating of the magnesium.

[0089] The gas pipeline system includes high-temperature resistant pipelines, pressure relief devices, oxygen content sensors, gas flow meters, vacuum devices, valve bodies, pipeline cooling devices, pipeline temperature sensors and filtering devices. Each device has a corresponding pipeline connection to ensure the normal operation of the equipment. The pipeline at the gas outlet should be equipped with a pipeline cooling device and a pipeline temperature sensor. Considering the high temperature of the reaction shell 13 (300℃+), the gas temperature should be lowered by temperature control measures to prevent burns or hydrogen self-ignition, or damage to the rear control valve.

[0090] Since magnesium releases heat when absorbing hydrogen, and reaches equilibrium at a certain temperature under a certain pressure, and the desorption temperature is higher than the absorption temperature, the hydrogen release capacity of the pipeline must be guaranteed first. The hydrogen absorption and desorption process in the reversal device can be controlled by rapid pressure relief measures, and the safety of the high-pressure container can be guaranteed based on this principle.

[0091] The control system mainly controls the reaction temperature, pressure, duration, etc. in the bottle, and fits and adjusts the reaction parameters based on the initial theoretical reaction curve. On the other hand, during the hydrogen release reaction, the reaction state can be controlled to stabilize the hydrogen release rate and the hydrogen flow rate.

[0092] Since the hydrogen stored and transported is solid magnesium hydride, trace amounts of magnesium may be carried along with the high-speed airflow during hydrogen release. Therefore, a filter device should be installed at the connection between the reaction shell 13 and the pipeline. This filter device will filter out the hydrogen during hydrogen release, retaining the magnesium and magnesium hydride at the outlet of the reaction shell 13. During reverse hydrogen injection, the magnesium and magnesium hydride powder accumulated at the outlet will be blown back into the reaction shell 13 to reduce pipeline blockage. This device is in a repeated hydrogen absorption and desorption mode, so it can continuously self-clean its filter.

[0093] The present invention provides a process for preparing solid magnesium hydride from cracked crushed metal magnesium, which reduces the problems of high power consumption and requirements of traditional magnesium hydride production, and does not require the addition of any alloy to the magnesium to promote the reaction, can effectively utilize energy, reduce heat loss, and ensure stable control.

[0094] By cutting magnesium chips 5 and aggregating them into magnesium plates 3, the advantages of solid magnesium hydride for hydrogen storage and transportation are effectively realized, and the energy of the heating device can be fully absorbed to reduce operating losses;

[0095] In addition, the preparation of magnesium chips 5 is different from the special requirements of solid magnesium hydride for magnesium. This process is simple and easy to implement. The magnesium chips 5 waste generated by the traditional magnesium machining industry can also be collected and used, which greatly reduces the cost.

[0096] On the other hand, the temperature of the traditional magnesium hydride reaction is greatly reduced, and the overall temperature is controlled below the ignition point of hydrogen, which improves the safety of hydrogen use and the safety of magnesium hydride production;

[0097] The present reaction apparatus 1 employs a bidirectional design, a dual-purpose design that can stably produce solid magnesium hydride and stably release hydrogen from the magnesium hydride. Specifically, hydrogen is collected in areas with high levels of waste hydrogen and safely transported at low pressure to areas with high hydrogen demand for further release. The heating device and the solid magnesium hydride can also be removed and transported separately, reducing hydrogen transportation costs to a certain extent and improving the convenience of hydrogen use.

[0098] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A process for preparing solid magnesium hydride from cracked crushed magnesium metal, characterized in that: The following steps are included: Step S1: Cutting a bulk metal ingot into crushed metal chips; Step S2: performing a primary extrusion operation on the metal chips, wherein the extrusion force applied to the metal chips is greater than the ultimate stress of the metal chips, so that cracks are generated on the surface of the metal chips after extrusion; Step S3: placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction.

2. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 1, characterized in that: The step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes: Step S31: first, the extruded metal chips are loaded into a material frame; Step S32: placing the material frame containing the metal chips into the reaction device, and introducing hydrogen to carry out the reaction.

3. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 1, characterized in that: The step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes: Step S3a: pressing the extruded metal chips to form granular metal particles; Step S3b: placing the metal particles into the reaction device and introducing hydrogen to carry out the reaction.

4. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 3, characterized in that: In step S3b, an inner cylinder is provided in the reaction device. The inner cylinder is made of a flexible expansion restraint net. The metal pellets are placed in the inner cylinder. An expansion gap exists between the inner cylinder and the outer wall of the reaction device.

5. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 4, characterized in that: The material of the inner cylinder is titanium metal.

6. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 1, characterized in that: The step S3 of placing the metal chips into a reaction device and introducing hydrogen to carry out the reaction specifically includes: Step S3A: Filling the extruded metal chips into a woven mesh bag and compacting it, and then sealing the filling port of the woven mesh bag; Step S3B: performing an oscillating operation on the woven mesh bag containing the metal chips; Step S3C: rolling or pressing the woven mesh bag containing the metal chips to form a metal plate with a plate-like structure or processing it into a shape matching the reaction device; Step S3D: Wrapping the metal plate around the heating structure in the reaction device, and introducing hydrogen to carry out the reaction.

7. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 6, characterized in that: The material used for the woven mesh bag is a metal catalyst.

8. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 6, characterized in that: The reaction device includes a reaction shell, a heating structure, a heat exchange system, a temperature detection system, a pressure detection system, a gas pipeline system and a control system. At least one columnar heating structure is installed inside the reaction shell. The heat exchange system, the temperature detection system, the pressure detection system and the gas pipeline system are all installed on the reaction shell. The heating structure, the heat exchange system, the temperature detection system, the pressure detection system and the gas pipeline system are all connected to the control system. The control system can control the operation of the heating structure and the heat exchange system. The temperature detection system can detect the temperature of the heating structure and the heat exchange system in real time and transmit the detected temperature information to the control system. The pressure detection system can detect the pressure in the reaction shell in real time and transmit the detected pressure information to the control system.

9. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 8, characterized in that: The gas pipeline system includes a high-temperature resistant pipeline, a pressure relief device, an oxygen content sensor, a gas flow meter, a vacuum device, a valve body, a pipeline cooling device, a pipeline temperature sensor and a filtering device.

10. The process for preparing solid magnesium hydride from cracked crushed magnesium metal according to claim 1, characterized in that: In the step S1, the block metal ingot is cut into the crushed metal chips by using a stepping cutting tool, and the stepping of the stepping cutting tool is less than or equal to 0.2 mm.

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