Metal hydride hydrogen storage system and hydrogen absorption and desorption method

Abstract

The invention relates to the technical field of hydrogen storage, and discloses a metal hydride hydrogen storage system and a hydrogen absorption and desorption method. The metal hydride hydrogen storage system comprises n hydrogen storage units which are connected in series, and n is 3-20 and is a positive integer; the adjacent hydrogen storage units are connected through a detachable connecting unit, an open hole is formed in the detachable connecting unit, and the open hole is used for circulation of hydrogen; the hydrogen storage unit comprises a tank body, the tank body is filled with a hydrogen storage bed layer, and the hydrogen storage bed layer is used for hydrogen absorption / hydrogen desorption and heat conduction. According to the hydrogen storage system, the hydrogen storage volume can be flexibly controlled, hydrogen storage material filling is simpler, the heat transfer efficiency can be improved, and the hydrogen absorption and desorption rate can be better controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage, and in particular to a metal hydride hydrogen storage system and a method for absorbing and releasing hydrogen. Background Art

[0002] As a secondary energy source, hydrogen energy has the characteristics of wide sources, clean and carbon-free, flexible and efficient, and a wide range of application scenarios. It can be widely used in energy, transportation, industry, construction and other fields. It is an ideal interconnected medium to promote the clean and efficient use of traditional fossil energy and support the large-scale development of renewable energy. It will gradually become an important direction for the development of global energy technology.

[0003] Hydrogen can be stored and transported, but due to its low density and low volume energy density, it has become one of the key factors restricting the development of hydrogen energy. Improving the efficiency of hydrogen storage and transportation and reducing the cost of hydrogen storage and transportation are the development focuses of hydrogen storage and transportation technology. Common hydrogen storage methods include high-pressure gaseous hydrogen storage, liquid hydrogen, organic liquid hydrogen storage and solid hydrogen storage. For high-pressure gaseous hydrogen storage, its volume hydrogen storage density is low and the hydrogen storage pressure is high (35-70 MPa), which poses a high safety risk; liquid hydrogen needs to be stored below 20 K, and the liquefaction process has high energy consumption and evaporation losses during use, which is an urgent problem to be solved; organic liquids have problems such as low hydrogen release purity and poor cycle performance, which still need further research. Solid-state hydrogen storage provides a feasible hydrogen storage solution with high volume hydrogen storage density, low working pressure and good reversibility. It has broad application prospects in transportation, microgrids, hydrogen compression, heat storage and other fields.

[0004] Hydrogen storage alloy materials refer to a type of material that stores hydrogen in the form of metal hydrides. Hydrogen storage alloys have the advantages of good reversibility of hydrogen absorption and desorption, high hydrogen storage density per unit volume, high purity of hydrogen desorption, and high safety. Metal hydrides are formed by a reversible reaction between metal alloys and hydrogen at specific temperatures and pressures. The absorption of hydrogen is an exothermic reaction, while desorption is an endothermic process. The former only occurs when the supply pressure is greater than the equilibrium pressure, and the latter only occurs when the pressure is lower than the equilibrium pressure. During the hydrogen absorption process, the released heat needs to be removed from the reaction system in a timely manner to keep the temperature at a favorable position. This helps to increase the hydrogen absorption rate and the hydrogen storage capacity at the same time. When hydrogen needs to be released, the endothermic reaction of the desorption process means that heat needs to be provided from the outside to maintain a suitable hydrogen desorption rate. However, the existing hydrogen storage alloy reactors have poor heat transfer performance, low thermal conductivity of the hydrogen storage bed, and inconvenient filling of hydrogen storage materials, resulting in poor control of the hydrogen absorption and desorption rate of the hydrogen storage system and low reversible hydrogen storage density. Therefore, improving the system heat transfer efficiency and the thermal conductivity of the hydrogen storage bed is crucial to improving the performance of the metal hydride hydrogen storage system. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of inconvenient filling of hydrogen storage materials, poor heat transfer efficiency of hydrogen storage systems and difficult control of hydrogen absorption and desorption rates in the prior art, and to provide a metal hydride hydrogen storage system and a method for hydrogen absorption and desorption. The hydrogen storage system can flexibly control the hydrogen storage volume, the filling of hydrogen storage materials is simpler, and the heat transfer efficiency can be improved and the hydrogen absorption and desorption rates can be better controlled.

[0006] In order to achieve the above object, the first aspect of the present invention provides a hydrogen storage system, wherein the hydrogen storage system comprises n hydrogen storage units connected in series, wherein n is 3-20, and n is a positive integer; Adjacent hydrogen storage units are connected via a detachable connection unit, and the detachable connection unit is provided with an opening for the circulation of hydrogen; The hydrogen storage unit comprises a tank body, in which a hydrogen storage bed is filled. The hydrogen storage bed is used for absorbing / releasing hydrogen and conducting heat.

[0007] A second aspect of the present invention provides a method for absorbing and releasing hydrogen, wherein the method comprises: Hydrogen absorption reaction: hydrogen is introduced into the hydrogen storage system, and the hydrogen absorbs hydrogen with the hydrogen storage bed inside the hydrogen storage system, and the first heat transfer medium is used to absorb the heat generated by the hydrogen absorption reaction; Hydrogen desorption reaction: the hydrogen storage bed layer adsorbing hydrogen undergoes a hydrogen desorption reaction, and the second heat transfer medium is used to provide the heat required for the hydrogen desorption reaction; The hydrogen absorption reaction and hydrogen release reaction are carried out in the metal hydride hydrogen storage system described in the first aspect.

[0008] The inventor of the present invention has found that in the prior art, the hydrogen storage reactor is usually a single tank, and the filling of hydrogen storage materials is cumbersome; at the same time, the hydrogen storage reactor does not have openings to form gas flow channels, and there is no stacking of heat-conducting material pressed sheets, so the heat transfer efficiency is low and the hydrogen absorption and desorption rate is slow. The hydrogen storage system provided by the present invention is composed of n hydrogen storage units stacked in series, and the n hydrogen storage units are detachably connected. Each hydrogen storage unit is a modular structure and can be replaced individually, which is easy to control the volume of the hydrogen storage system and convenient for the filling of the hydrogen storage bed; the detachable connection unit of the hydrogen storage unit is provided with openings to form special gas flow channels (preferably serpentine flow channels) to ensure that hydrogen and the hydrogen storage bed are fully in contact during the hydrogen storage process, and to ensure that the hydrogen storage bed can absorb hydrogen to improve the hydrogen absorption efficiency. Preferably, the hydrogen storage bed is confined to the hydrogen storage unit, and the heat change during the hydrogen absorption and desorption process is more uniform. At the same time, the concentrated stress caused by the expansion of the hydrogen storage material in the large container can be avoided. The hydrogen storage bed is provided with hydrogen storage pressed sheets and heat-conducting pressed sheets to increase the heat transfer coefficient and heat exchange area of ​​the bed, thereby improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of a metal hydride hydrogen storage system of the present invention; Figure 2 is a schematic diagram of a detachable connection unit of the present invention; Figure 3 is a curve showing the change of hydrogen absorption rate with relative hydrogen absorption amount in Example 1 of the present invention; Figure 4 is a curve showing the variation of the average temperature of the hydrogen storage tablet with the hydrogen absorption time in Example 1 of the present invention; Figure 5 is a curve showing the change of hydrogen absorption rate with relative hydrogen absorption amount in Example 2 of the present invention; Figure 6 is a curve showing the variation of the average temperature of the hydrogen storage tablet with the hydrogen absorption time in Example 2 of the present invention; Figure 7 is a curve showing the change of hydrogen absorption rate with relative hydrogen absorption amount in Example 3 of the present invention; Figure 8 is a curve showing the variation of the average temperature of the hydrogen storage tablet with the hydrogen absorption time in Example 3 of the present invention; Fig. 9 is a curve showing the change of hydrogen absorption rate with relative hydrogen absorption amount in Example 4 of the present invention; Fig.10 is a curve showing the variation of the average temperature of the hydrogen storage tablet with the hydrogen absorption time in Example 4 of the present invention; Fig.11 is a curve showing the change of hydrogen absorption rate with relative hydrogen absorption amount in comparative example 1 of the present invention; Fig.12 This is a curve showing the change of the average temperature of the hydrogen storage tablet in comparative example 1 of the present invention as a function of the hydrogen absorption time.

[0010] Description of Reference Numerals 1-Hydrogen storage unit 2-Tank 3-Removable connection unit 4-Sealing ring 5- opening 6- trachea 7-Filter DETAILED DESCRIPTION The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0011] In the description of the present invention, the directions or positional relationships indicated by terms such as "vertical", "horizontal", "top", "bottom", etc. are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0012] The first aspect of the present invention provides a metal hydride hydrogen storage system, such as Figure 1 As shown, the hydrogen storage system comprises n hydrogen storage units 1 connected in series, wherein n is 3-20 and n is a positive integer; Adjacent hydrogen storage units 1 are connected via a detachable connection unit 3, and an opening 5 is provided on the detachable connection unit 3, and the opening 5 is used for the circulation of hydrogen; The hydrogen storage unit 1 comprises a tank body 2, wherein the tank body 2 is filled with a hydrogen storage bed layer, and the hydrogen storage bed layer is used for absorbing / releasing hydrogen and conducting heat.

[0013] In the present invention, n series-connected hydrogen storage units are selected to be detachably connected in the vertical direction as the hydrogen storage system, and the volume of the hydrogen storage system can be adjusted by changing the number of hydrogen storage units, and the filling of the hydrogen storage bed is convenient, thereby improving the hydrogen storage efficiency. Furthermore, the detachable connection unit is provided with openings, and the plurality of openings form a gas flow channel, so that the interior of the hydrogen storage system presents a special gas flow channel structure such as a serpentine flow channel, thereby realizing the safe and efficient transportation of hydrogen and the absorption and release of heat; further, hydrogen flows in the gas flow channel of the hydrogen storage system, and the flow direction of hydrogen can be flexibly controlled by adjusting the relative position of the openings on the detachable connection unit.

[0014] In the present invention, there is no particular limitation on the manner of detachable connection. For example, the detachable connection may be a threaded connection, and the present invention is only schematically described using a threaded connection.

[0015] In the present invention, there is no particular limitation on the material of the tank body and the detachable connection unit. Preferably, the material of the tank body 2 and the detachable connection unit 3 is independently selected from at least one of aluminum, aluminum alloy, copper, copper alloy, carbon steel and stainless steel. The advantage of adopting this preferred embodiment is that the parameters such as the tank body weight, cost, and thermal conductivity can be adjusted according to the application scenario.

[0016] In the present invention, preferably, n is 3-10, and n is a positive integer, for example, it can be 3, 4, 5, 6, 7, 8, 9, 10, and values ​​between any two groups. By controlling the number of n, the hydrogen storage volume of the hydrogen storage system can be flexibly adjusted, which is suitable for different application scenarios. When n is not within the above preferred range, the aspect ratio of the hydrogen storage system is too long, and the bottom hydrogen storage unit has a higher load-bearing capacity when placed vertically, which increases the danger.

[0017] In the present invention, there is no particular limitation on the height of the tank of the hydrogen storage system, and those skilled in the art can set it according to actual needs. Preferably, the height of the tank 2 is 50-600 mm, and more preferably 50-300 mm.

[0018] In the present invention, there is no particular limitation on the inner diameter of the tank of the hydrogen storage system, and those skilled in the art can set it according to actual needs. Preferably, the inner diameter of the tank 2 is 10-100 mm, and more preferably 20-50 mm.

[0019] The advantages of adopting the above preferred embodiment are that it is easy to fill the hydrogen storage bed and improve the heat exchange efficiency.

[0020] In the present invention, in order to realize flexible regulation of the hydrogen storage unit, the present invention realizes the connection of each hydrogen storage unit through a detachable connection unit, and the present invention does not particularly limit the specific structure of the detachable connection unit. Figure 2 As shown, preferably, the detachable connection unit 3 includes a disc detachably connected to the tank body 2, and the opening 5 is formed on the disc. Preferably, the detachable connection unit 3 also includes a partition integrally connected to the outer peripheral wall of the disc, and the edge of the partition is a regular polygon concentric with the disc. The present invention has no particular limitation on the shape of the regular polygon, as long as it is convenient for the disassembly of the detachable connection unit, for example, it can be a regular pentagon, a regular hexagon, etc.

[0021] In the present invention, preferably, a sealing ring 4 is sleeved on the outer peripheral wall of the disc, and the sealing ring 4 is used to seal the tank body 2. In the present invention, there is no particular limitation on the shape of the sealing ring, and preferably, the sealing ring is an O-ring.

[0022] In the present invention, there is no particular limitation on the material of the sealing ring. Preferably, the material of the sealing ring is selected from one of silicone, rubber, fluororubber and PTFE (polytetrafluoroethylene). The advantage of adopting this preferred embodiment is that it can meet the sealing requirements of the device according to the application scenario, and adjust the parameters such as the tank cost.

[0023] In the present invention, preferably, the ratio of the opening area of ​​the opening 5 to the area of ​​the disc is 0.02-0.15:1, and further preferably 0.04-0.1:1; the advantage of adopting this preferred embodiment is that the gas can flow along the openings of adjacent detachable connecting units to form a flow direction while taking into account the gas transmission efficiency.

[0024] In the present invention, preferably, the diameter of the opening 5 is 3-20 mm, more preferably 5-15 mm. The advantage of adopting this preferred embodiment is that the gas can flow along the openings of adjacent detachable connection units to form a flow direction, while taking into account the gas transmission efficiency.

[0025] In the present invention, the selection range of the position of the opening is relatively wide, and it can be set at the center of the disk or at a non-center position, preferably at a non-center position. More preferably, the ratio of the distance between the center of the disk and the center of the opening 5 to the diameter of the disk is 0.25-0.4:1, and more preferably 0.25-0.38:1. The advantage of adopting this preferred embodiment is that the contact time between the gas and the hydrogen storage bed is increased when the gas flows through the openings of adjacent detachable connection units.

[0026] In the present invention, gas flow channels are formed by setting openings 5 ​​on different hydrogen storage units. The present invention has a wide range of selection for the relative position of the openings on each hydrogen storage unit, and can form vertical flow channels, irregular flow channels, regular flow channels, such as serpentine flow channels, and more preferably serpentine flow channels. In the present invention, preferably, taking the openings 5 ​​on the detachable connecting unit 3 at the bottom end of the lowest hydrogen storage unit as a reference, from bottom to top, the openings 5 ​​are rotated in the same direction 90-180°, preferably 140-180°, along the axial direction of the tank body 2. The advantage of adopting this preferred embodiment is that a specific gas flow channel structure is formed, so that hydrogen is fully in contact with the hydrogen storage material, thereby improving the heat exchange efficiency.

[0027] In the present invention, it should be noted that, in the initial state, the centers of the openings on the detachable connection units of the n hydrogen storage units are on the same axis, and "rotating in the same direction" means that the opening on the detachable connection unit 3 at the bottom of the lowest hydrogen storage unit is the first opening, and the first opening remains stationary, and relative to the first opening, the second opening rotates 90-180° counterclockwise along the axis of the tank body; after the second opening is rotated, the second opening remains stationary, and relative to the second opening, the third opening continues to rotate 90-180° counterclockwise along the axis of the tank body, and so on, so that the openings from bottom to top in the hydrogen storage system form a gas flow channel structure, such as a serpentine flow channel. It should be noted that the aforementioned content is only schematically illustrated by counterclockwise rotation, and it can also be clockwise rotation, as long as the rotation directions of the multiple openings remain consistent.

[0028] In the present invention, there is no particular limitation on the filling height of the hydrogen storage bed, as long as the storage and release of hydrogen and heat conduction can be achieved. Preferably, the ratio of the height of the hydrogen storage bed to the height of the tank body 2 is 0.7-0.95:1, and more preferably 0.85-0.95:1. The advantage of adopting this preferred embodiment is to reduce the stress on the tank wall of the hydrogen storage unit caused by the expansion of the hydrogen storage material during the hydrogen absorption and desorption process.

[0029] In the present invention, there is no particular limitation on the composition of the hydrogen storage bed, as long as it can achieve the storage and release of hydrogen and heat conduction. Preferably, the hydrogen storage bed is filled with hydrogen storage alloy and heat conductive material, and there is no particular limitation on the filling method of the two. Preferably, the hydrogen storage bed includes hydrogen storage pressed sheets and heat conductive pressed sheets.

[0030] In the present invention, there is no particular limitation on the arrangement of the sheets in the hydrogen storage bed. For example, they can be stacked alternately in the form of ABABAB, or in the form of AABAAB, or in the form of ABBABB. Those skilled in the art can choose according to actual needs. Preferably, the hydrogen storage bed is formed by stacking hydrogen storage sheets and heat-conducting sheets. More preferably, the hydrogen storage bed is formed by stacking hydrogen storage sheets and heat-conducting sheets alternately in sequence. This preferred embodiment is more conducive to the smooth storage and release of hydrogen and heat conduction.

[0031] In the present invention, there is no particular limitation on the filling height of the hydrogen storage tablet, and those skilled in the art can select it according to actual needs. Preferably, the filling height of the hydrogen storage tablet is 5-50 mm, and more preferably 5-20 mm. The advantage of adopting this preferred embodiment is that it is easy to form the hydrogen storage tablet, and at the same time reduces the stress caused by material expansion during the hydrogen absorption and desorption process.

[0032] In the present invention, there is no particular limitation on the filling height of the heat-conducting pressing sheet, and those skilled in the art can select it according to actual needs. Preferably, the filling height of the heat-conducting pressing sheet is 1-10 mm, and more preferably 1-6 mm. The advantages of adopting this preferred embodiment are to improve the thermal conductivity of the hydrogen storage bed, reduce the stress caused by the expansion of the hydrogen storage pressing sheet on the hydrogen storage system, and extend the service life of the hydrogen storage system.

[0033] In the present invention, there is no particular limitation on the components of the hydrogen storage tablet and the amount of each component. Preferably, the hydrogen storage tablet comprises a hydrogen storage alloy and a thermal conductive material, and in the hydrogen storage tablet, the mass ratio of the hydrogen storage alloy to the thermal conductive material is 1:0.01-0.2.

[0034] In the present invention, there is no particular limitation on the forming method of the hydrogen storage pressed sheet. Preferably, the hydrogen storage pressed sheet is made of hydrogen storage alloy and heat conductive material by pressing.

[0035] In the present invention, there is no particular limitation on the type of hydrogen storage alloy, and it can be any hydrogen storage alloy conventionally defined in the art. Preferably, the hydrogen storage alloy is selected from at least one of titanium hydrogen storage alloys, zirconium hydrogen storage alloys, vanadium hydrogen storage alloys and rare earth hydrogen storage alloys, for example, it can be LaNi5 alloy.

[0036] In the present invention, there is no particular limitation on the type of thermally conductive material, and it can be any thermally conductive material conventionally defined in the art. Preferably, the thermally conductive material is selected from at least one of expanded graphite, thermally conductive fiber, graphite sheet, carbon nanotube, aluminum powder, copper powder, titanium powder, foamed aluminum, foamed nickel, and foamed copper.

[0037] In the present invention, there is no particular limitation on the material of the thermally conductive pressing sheet. Preferably, the material of the thermally conductive pressing sheet is selected from at least one of expanded graphite, thermally conductive fiber, graphite sheet, carbon nanotube, aluminum powder, copper powder, titanium powder, foamed aluminum, foamed nickel and foamed copper. In the present invention, there is no particular limitation on the molding method of the thermally conductive pressing sheet, and those skilled in the art can select it according to actual needs.

[0038] In the present invention, preferably, the system further comprises an air pipe 6 connected to the hydrogen storage unit 1, and the air pipe 6 is used to introduce hydrogen into the hydrogen storage unit 1 or release the hydrogen in the hydrogen storage unit 1. In the present invention, there is no particular limitation on the arrangement of the air pipe, as long as the introduction and release of hydrogen can be achieved. The air pipe can be connected to n hydrogen storage units respectively, or to any one of the n hydrogen storage units. Preferably, the air pipe 6 is connected to the uppermost hydrogen storage unit 1. Those skilled in the art can adjust it according to actual needs, so as to flexibly adjust the hydrogen storage amount to suit different hydrogen storage scenarios.

[0039] In the present invention, preferably, a filter 7 is provided inside the air pipe 6. In the present invention, there is no particular limitation on the arrangement of the filter, as long as the hydrogen can be filtered, for example, it can be arranged at the air inlet of the air pipe, or at the air outlet of the air pipe, and those skilled in the art can adjust it based on actual needs.

[0040] In the present invention, there is no particular limitation on the material and molding method of the filter, and the conventional methods defined in the art are applicable to the present invention. Preferably, the filter 7 is a copper-based and / or stainless steel-based porous sintered body, preferably a copper-based and / or stainless steel-based porous sintered body sintered by a powder metallurgy method.

[0041] In the present invention, there is no particular limitation on the filtering accuracy of the filter, as long as the hydrogen can be filtered, and those skilled in the art can adjust it according to actual needs. Preferably, the accuracy of the filter 7 is 0.5-2 μm.

[0042] A second aspect of the present invention provides a method for absorbing and releasing hydrogen, wherein the method comprises: Hydrogen absorption reaction: hydrogen is introduced into the hydrogen storage system, the hydrogen undergoes a hydrogen absorption reaction with the hydrogen storage bed inside the hydrogen storage system, and the first heat conducting medium is used to absorb the heat generated by the hydrogen absorption reaction; Hydrogen desorption reaction: the hydrogen storage bed layer adsorbing hydrogen undergoes a hydrogen desorption reaction, and the second heat conducting medium is used to provide heat required for the hydrogen desorption reaction; The hydrogen absorption reaction and hydrogen release reaction are carried out in the metal hydride hydrogen storage system described in the first aspect.

[0043] According to a specific embodiment of the present invention, the method of absorbing and releasing hydrogen is carried out in the hydrogen storage system described in the first aspect. In the present invention, there is no particular limitation on the method of absorbing and releasing hydrogen. For example, it can be carried out in the following manner: specifically, hydrogen is passed from the inlet of the gas pipe 6 from top to bottom into the n series-connected hydrogen storage units 1, the n series-connected hydrogen storage units 1 are threadedly connected through the detachable connection unit 3, the openings 5 ​​on the multiple detachable connection units 3 form a gas flow channel (preferably a serpentine flow channel), the hydrogen flows in the tank body 2 through the gas flow channel, and contacts with the hydrogen storage bed in the tank body 2 to perform a hydrogen absorption reaction, the hydrogen storage bed includes a hydrogen storage press sheet and a heat conductive press sheet. The heat generated by the hydrogen absorption reaction is transferred to the outer wall of the tank body through the heat-conducting pressing plate. The first heat-conducting medium absorbs the heat generated by the hydrogen absorption reaction and releases it into the atmosphere. During the hydrogen absorption reaction, hydrogen is continuously introduced and continuously absorbed in the n hydrogen storage units. When the required hydrogen storage amount is reached, hydrogen is released. After the hydrogen absorption reaction is completed, the hydrogen storage unit adsorbed with hydrogen is subjected to a hydrogen release reaction. The hydrogen circulation method is the same as the hydrogen absorption reaction, and the second heat-conducting medium is used to provide the heat required for the hydrogen release reaction. The detachably connected hydrogen storage unit 1 is convenient for the flexible absorption and release of hydrogen, so as to realize the flexible adjustment of the hydrogen storage amount and the safe and efficient transportation of hydrogen.

[0044] The present invention does not specifically limit the types of the first heat transfer medium and the second heat transfer medium, and those skilled in the art can select them according to actual needs. Preferably, the first heat transfer medium and the second heat transfer medium are each independently air and / or water vapor.

[0045] In the present invention, there is no particular limitation on the conditions of the hydrogen absorption reaction. Preferably, the conditions of the hydrogen absorption reaction include: a temperature of 10-50°C, a pressure of 0.5-50 MPa, and a temperature of the first heat transfer medium of 10-50°C.

[0046] In the present invention, there is no particular limitation on the conditions for the dehydrogenation reaction. Preferably, the conditions for the dehydrogenation reaction include: a temperature of 30-100°C, a pressure of 0.1-50 MPa, and a temperature of the second heat transfer medium of 30-100°C.

[0047] The present invention will be described in detail below through examples.

[0048] Example 1 like Figure 1 As shown, the metal hydride hydrogen storage system is composed of four hydrogen storage units 1 connected in series in the vertical direction. Each hydrogen storage unit 1 is threadedly connected by a detachable connection unit 3. The hydrogen storage unit 1 includes a tank body 2 and a sealing ring 4. The tank body 2 is filled with a hydrogen storage bed to achieve hydrogen absorption, hydrogen release and heat conduction. The tank body 2 and the detachable connection unit 3 are both made of 304 stainless steel. The height of the tank body 2 is 60mm and the inner diameter is 30mm; the air pipe 6 is arranged at the top of the hydrogen storage system and is connected to the uppermost hydrogen storage unit 1. The diameter of the air pipe 6 is 6mm. A filter 7 is arranged inside the air pipe 6. The filter 7 is made of sintered 316L stainless steel with an accuracy of 2μm. The hydrogen enters or is discharged from the hydrogen storage system through the air pipe 6 after being filtered by the filter 7.

[0049] like Figure 1 and Figure 2 As shown, the detachable connection unit 3 includes a disc threadedly connected to the tank body 2 and a partition integrally connected to the outer peripheral wall of the disc, the edge of the partition is a regular hexagon concentric with the disc, and a sealing ring 4 is sleeved on the outer peripheral wall of the disc to facilitate sealing the tank body 2. An opening 5 is opened on the disc, the diameter of the opening 5 is 6mm, the ratio of the opening area of ​​the opening 5 to the area of ​​the disc is 0.04:1, and the ratio of the distance between the center of the disc and the center of the opening 5 to the diameter of the disc is 0.25:1; taking the opening 5 on the detachable connection unit 3 at the bottom end of the lowest hydrogen storage unit 1 as a reference, from bottom to top, the openings 5 ​​are arranged in the same direction by rotating 180° in sequence along the axial direction of the tank body 2, and multiple openings 5 ​​form a gas flow channel, and hydrogen flows in the gas flow channel and contacts with the hydrogen storage bed to absorb and release hydrogen.

[0050] like Figure 1 As shown, the hydrogen storage sheets and the heat-conducting sheets are alternately stacked in sequence to form a hydrogen storage bed layer filled in the tank body 2, and the ratio of the height of the hydrogen storage bed layer to the height of the tank body 2 is 0.93:1. The hydrogen storage sheets are made of LaNi5 alloy and expanded graphite sheets, the mass ratio of LaNi5 alloy to expanded graphite is 1:0.05, the height of the hydrogen storage sheets is 10 mm, and the height of the heat-conducting sheets is 1.5 mm.

[0051] In the hydrogen absorption reaction, the hydrogen inlet pressure rises to 0.8MPa in 1s and is maintained at 0.8MPa before being introduced into the hydrogen storage system, where it undergoes a hydrogen absorption reaction with the hydrogen storage alloy in the hydrogen storage system at an initial temperature of 293K. The air outside the hydrogen storage system is at 293K, which absorbs the heat generated by the hydrogen absorption reaction. Hydrogen desorption reaction: the hydrogen storage alloy adsorbed with hydrogen undergoes a hydrogen desorption reaction at an initial temperature of 343K and a constant outlet pressure of 0.1MPa; the air outside the hydrogen storage system is 343K to provide the heat required for the hydrogen desorption reaction.

[0052] Comsol software is used to perform numerical simulation calculations on the hydrogen storage system. The mass, energy and momentum balance equations are constructed. The specific equations are as follows: Mass conservation equation for hydrogen storage alloys: The mass conservation equation for gases is: in, m is the mass change value, ε 1 and ε 2 are the porosity of the hydrogen storage tablet and the heat conduction tablet, a is the actual mass of hydrogen storage alloy in hydrogen storage tablets and The mass ratio, b is the volume ratio of hydrogen storage tablets to hydrogen storage bed, ρ s is the density of hydrogen storage alloy, t is the reaction time, u g is the velocity field of hydrogen, ρ g is the gas density.

[0053] The velocity field for hydrogen is calculated using Darcy's law: in, K is the permeability, μ g is the viscosity coefficient of hydrogen, P g is the hydrogen pressure.

[0054] For the hydrogen absorption reaction, the reaction rate equation is as follows: For the hydrogen evolution reaction, the reaction rate equation is as follows: in, C a and C d are the pre-exponential factors of hydrogen absorption and desorption reactions, E a and E d are the activation energies of hydrogen absorption and desorption reactions, respectively. R g is the gas constant, T is the reaction temperature, P eq To balance the pressure for chemical reactions, ρ ss is the density of the hydrogen storage alloy after hydrogen absorption is complete, ρ 0 is the initial density of the hydrogen storage alloy.

[0055] The equilibrium pressure of a chemical reaction is given by the Van't Hoff equation: The energy balance equation for the hydrogen absorption and desorption reaction in the inner tank 1 is as follows: in, M g is the molar mass of hydrogen.

[0056] Among them, the effective heat capacity of the hydrogen storage tablet is: The effective thermal conductivity of the hydrogen storage tablet is: The effective heat capacity of the thermally conductive sheet is: The effective thermal conductivity of the thermally conductive sheet is: in, C p,g , C p,s1 and C p,st are the heat capacities of hydrogen, hydrogen storage sheet and heat conducting sheet respectively, g , s and λ st are the thermal conductivities of hydrogen, hydrogen storage tablets and thermal conductive tablets, respectively. ρ s1 and ρ st They are the densities of the hydrogen storage tablet and the heat conducting tablet respectively.

[0057] For the heat transfer medium, the mass balance equation is: in, ρ f is the density of the heat transfer medium, u f is the velocity field of the heat transfer medium.

[0058] For heat conducting media, the momentum balance equation is as follows: The heat transfer equation inside the heat conducting medium is as follows: in: in, C p,f is the heat capacity of the heat conducting medium, λ f is the effective thermal conductivity of the heat-conducting medium, P f is the pressure of the heat transfer medium.

[0059] For the tank wall and the removable connection unit, the heat transfer equation is as follows: in, is the heat capacity of the solid (tank wall or removable connection unit), is the effective thermal conductivity of the solid (tank wall or removable connection unit).

[0060] The heat transfer equation between the hydrogen storage bed (including hydrogen storage sheets and heat-conducting sheets), solid (tank wall or detachable connection unit), and heat-conducting medium is: in, q is the heat flux, h is the heat transfer coefficient between the two, T 1 and T 2 refers to the respective temperatures of two adjacent phases with different temperatures (for example, when calculating heat transfer between a solid and a heat-conducting medium, T 1 and T 2 refers to the temperature of the contact surface between the solid and the heat conducting medium).

[0061] Using the above equation, the change values ​​of various parameters in the hydrogen storage system are calculated. Figure 3 As shown in the curve of hydrogen absorption rate versus relative hydrogen absorption amount, when the hydrogen absorption rate drops to 0.0083wt% / s, the relative hydrogen absorption amount is 73%, which is 2.6 times that of comparative example 1, indicating that the hydrogen storage system can absorb more hydrogen at a faster rate; Figure 4 The average temperature of the hydrogen storage tablets shown in the figure changes with the hydrogen absorption time. After the hydrogen absorption starts, the average temperature of the hydrogen storage tablets rises rapidly, and after 5485s the temperature drops to 310K, which is 27% less than that of comparative example 1, indicating that the system has better heat exchange capacity, can increase the heat exchange rate of the hydrogen absorption and desorption process, and is beneficial to increasing the hydrogen absorption and desorption reaction rate.

[0062] Example 2 The hydrogen storage system of Example 1 and the method of Example 1 are used, except that the metal hydride hydrogen storage system is composed of 7 hydrogen storage units 1 connected in series in the vertical direction. The tank body 2 and the detachable connection unit 3 are both made of 304 stainless steel. The height of the tank body 2 is 130 mm and the inner diameter is 20 mm; the air pipe 6 is arranged at the top of the hydrogen storage system and is connected to the uppermost hydrogen storage unit 1. The diameter of the air pipe 6 is 6 mm. A filter 7 is arranged inside the air pipe 6. The filter 7 is made of sintered 316L stainless steel with an accuracy of 2 μm. The hydrogen enters or is discharged from the hydrogen storage system through the air pipe 6 after being filtered by the filter 7.

[0063] like Figure 1 and Figure 2As shown, the detachable connection unit 3 includes a disc threadedly connected to the tank body 2 and a partition integrally connected to the outer peripheral wall of the disc, the edge of the partition is a regular hexagon concentric with the disc, and a sealing ring 4 is sleeved on the outer peripheral wall of the disc to facilitate sealing the tank body 2. An opening 5 is opened on the disc, the diameter of the opening 5 is 5mm, the ratio of the opening area of ​​the opening 5 to the area of ​​the disc is 0.06:1, and the ratio of the distance between the center of the disc and the center of the opening 5 to the diameter of the disc is 0.3:1; taking the opening 5 on the detachable connection unit 3 at the bottom of the lowest hydrogen storage unit as a reference, from bottom to top, the openings 5 ​​are arranged in the same direction by rotating 145° in sequence along the axial direction of the tank body 2, and multiple openings 5 ​​form a gas flow channel, and hydrogen flows in the gas flow channel and contacts with the hydrogen storage bed to absorb and release hydrogen.

[0064] like Figure 1 As shown, the hydrogen storage sheets and the heat-conducting sheets are alternately stacked in sequence to form a hydrogen storage bed layer filled in the tank body 2, and the ratio of the height of the hydrogen storage bed layer to the height of the tank body 2 is 0.89:1. The hydrogen storage sheets are made of LaNi5 alloy and expanded graphite sheets, the mass ratio of LaNi5 alloy to expanded graphite is 1:0.05, the height of the hydrogen storage sheets is 20 mm, and the height of the heat-conducting sheets is 4 mm.

[0065] In the hydrogen absorption reaction, the hydrogen inlet pressure rises to 0.8MPa in 1s and is maintained at 0.8MPa before being introduced into the hydrogen storage system, where it undergoes a hydrogen absorption reaction with the hydrogen storage alloy in the hydrogen storage system at an initial temperature of 293K. The air outside the hydrogen storage system is at 293K, which absorbs the heat generated by the hydrogen absorption reaction. Hydrogen desorption reaction: the hydrogen storage alloy adsorbed with hydrogen undergoes a hydrogen desorption reaction at an initial temperature of 343K and a constant outlet pressure of 0.1MPa; the air outside the hydrogen storage system is 343K to provide the heat required for the hydrogen desorption reaction.

[0066] Comsol software is used to perform numerical simulation calculations on the hydrogen storage system. Figure 5 As shown in the curve of hydrogen absorption rate versus relative hydrogen absorption amount, when the hydrogen absorption rate drops to 0.0083wt% / s, the relative hydrogen absorption amount is 92%, which is 3.3 times that of comparative example 1, indicating that the hydrogen storage system can absorb more hydrogen at a faster rate; Figure 6 The average temperature of the hydrogen storage tablets shown in the figure changes with the hydrogen absorption time. The temperature rises rapidly after the hydrogen absorption starts, and drops to 310K after 3650s, which is 51% shorter than that of comparative example 1, indicating that the system has better heat exchange capacity, can increase the heat exchange rate of the hydrogen absorption and desorption process, and is beneficial to increasing the hydrogen absorption and desorption reaction rate.

[0067] Example 3 The hydrogen storage system and method of Example 1 are used, except that the metal hydride hydrogen storage system is composed of four hydrogen storage units 1 connected in series in a vertical direction. The tank body 2 and the detachable connection unit 3 are both made of 304 stainless steel. The height of the tank body 2 is 190 mm and the inner diameter is 40 mm.

[0068] like Figure 1 and Figure 2 As shown, the detachable connection unit 3 includes a disc threadedly connected to the tank body 2 and a partition integrally connected to the outer peripheral wall of the disc, the edge of the partition is a regular hexagon concentric with the disc, and a sealing ring 4 is sleeved on the outer peripheral wall of the disc to facilitate sealing the tank body 2. An opening 5 is opened on the disc, the diameter of the opening 5 is 12 mm, the ratio of the opening area of ​​the opening 5 to the area of ​​the disc is 0.09:1, and the ratio of the distance between the center of the disc and the center of the opening 5 to the diameter of the disc is 0.32:1; taking the opening 5 on the detachable connection unit 3 at the bottom of the lowest hydrogen storage unit as a reference, from bottom to top, the openings 5 ​​are arranged in the same direction by rotating 160° in sequence along the axial direction of the tank body 2, and multiple openings 5 ​​form a gas flow channel, and hydrogen flows in the gas flow channel and contacts with the hydrogen storage bed to absorb and release hydrogen.

[0069] like Figure 1 As shown, the hydrogen storage sheets and the heat-conducting sheets are alternately stacked in sequence to form a hydrogen storage bed layer filled in the tank body 2, and the ratio of the height of the hydrogen storage bed layer to the height of the tank body 2 is 0.91:1. The hydrogen storage sheets are made of LaNi5 alloy and expanded graphite sheets, the mass ratio of LaNi5 alloy to expanded graphite is 1:0.05, the height of the hydrogen storage sheets is 9 mm, and the height of the heat-conducting sheets is 6 mm.

[0070] In the hydrogen absorption reaction, the hydrogen inlet pressure rises to 0.8MPa in 1s and is maintained at 0.8MPa before being introduced into the hydrogen storage system, where it undergoes a hydrogen absorption reaction with the hydrogen storage alloy in the hydrogen storage system at an initial temperature of 293K. The air outside the hydrogen storage system is at 293K, which absorbs the heat generated by the hydrogen absorption reaction. Hydrogen desorption reaction: the hydrogen storage alloy adsorbed with hydrogen undergoes a hydrogen desorption reaction at an initial temperature of 343K and a constant outlet pressure of 0.1MPa; the air outside the hydrogen storage system is 343K to provide the heat required for the hydrogen desorption reaction.

[0071] Comsol software is used to perform numerical simulation calculations on the hydrogen storage system. Figure 7 As shown in the curve of hydrogen absorption rate versus relative hydrogen absorption amount, when the hydrogen absorption rate drops to 0.0083wt% / s, the relative hydrogen absorption amount is 87%, which is 3.1 times that of comparative example 1, indicating that the hydrogen storage system can absorb more hydrogen at a faster rate; Figure 8The average temperature of the hydrogen storage tablets shown in the figure changes with the hydrogen absorption time. The temperature rises rapidly after the hydrogen absorption starts, and drops to 310K after 5010s, which is 33% shorter than that of comparative example 1, indicating that the system has better heat exchange capacity, can increase the heat exchange rate of the hydrogen absorption and desorption process, and is beneficial to increasing the hydrogen absorption and desorption reaction rate.

[0072] Example 4 The hydrogen storage system and method of Example 1 are used, except that the centers of the multiple openings 5 ​​are located on the same axis from bottom to top, taking the opening 5 on the detachable connecting unit 3 at the bottom end of the lowest hydrogen storage unit as a reference.

[0073] In the hydrogen absorption reaction, the hydrogen inlet pressure rises to 0.8MPa in 1s and is maintained at 0.8MPa before being introduced into the hydrogen storage system, where it undergoes a hydrogen absorption reaction with the hydrogen storage alloy in the hydrogen storage system at an initial temperature of 293K. The air outside the hydrogen storage system is at 293K, which absorbs the heat generated by the hydrogen absorption reaction. Hydrogen desorption reaction: the hydrogen storage alloy adsorbed with hydrogen undergoes a hydrogen desorption reaction at an initial temperature of 343K and a constant outlet pressure of 0.1MPa; the air outside the hydrogen storage system is 343K to provide the heat required for the hydrogen desorption reaction.

[0074] Comsol software is used to perform numerical simulation calculations on the hydrogen storage system. Fig. 9 As shown in the curve of hydrogen absorption rate versus relative hydrogen absorption amount, when the hydrogen absorption rate drops to 0.0083wt% / s, the relative hydrogen absorption amount is 67%, which is 2.4 times that of comparative example 1, indicating that the hydrogen storage system can absorb more hydrogen at a faster rate; Fig.10 The average temperature of the hydrogen storage tablets shown in the figure changes with the hydrogen absorption time. The temperature rises rapidly after the hydrogen absorption starts, and drops to 310K after 5670s, which is 25% shorter than that of comparative example 1, indicating that the system has better heat exchange capacity, can increase the heat exchange rate of the hydrogen absorption and desorption process, and is beneficial to increasing the hydrogen absorption and desorption reaction rate.

[0075] Comparative Example 1 The method of Example 1 is followed, except that the metal hydride hydrogen storage system is a cylindrical tank with an opening and an air pipe on the top. The tank body is made of 304 stainless steel. The height of the tank body is 60 mm and the inner diameter is 30 mm; the air pipe is arranged at the top of the hydrogen storage system and is connected to the tank body. The diameter of the air pipe is 6 mm. A filter is arranged inside the air pipe. The filter is made of sintered 316L stainless steel with an accuracy of 2 μm. The hydrogen enters or is discharged from the hydrogen storage system through the air pipe after being filtered by the filter. An opening 5 is provided on the top of the tank body, and the diameter of the opening 5 is 6 mm. A hydrogen storage bed composed of hydrogen storage tablets is filled in the tank body. The hydrogen storage tablets are made of LaNi5 alloy and expanded graphite tablets, and the mass ratio of LaNi5 alloy to expanded graphite is 1:0.05.

[0076] In the hydrogen absorption reaction, the hydrogen inlet pressure rises to 0.8MPa in 1s and is maintained at 0.8MPa before being introduced into the hydrogen storage system, where it undergoes a hydrogen absorption reaction with the hydrogen storage alloy in the hydrogen storage system at an initial temperature of 293K. The air outside the hydrogen storage system is at 293K, which absorbs the heat generated by the hydrogen absorption reaction. Dehydrogenation reaction: the hydrogen storage alloy adsorbed with hydrogen undergoes dehydrogenation reaction at an initial temperature of 343K and a constant outlet pressure of 0.1MPa; the air outside the hydrogen storage system is 343K to provide the heat required for the dehydrogenation reaction. Fig.11 The curve of hydrogen absorption rate versus relative hydrogen absorption amount is shown in Figure 1. When the hydrogen absorption rate drops to 0.0083wt% / s, the relative hydrogen absorption amount is 28%. Fig.12 The average temperature of the hydrogen storage tablets shown changes with the hydrogen absorption time. The temperature rises rapidly after the hydrogen absorption begins, and drops to 310K after 7512s.

[0077] It can be seen from the above embodiments and comparative examples that the metal hydride hydrogen storage tank and hydrogen storage bed provided by the present invention have a better heat exchange effect, which is beneficial to the heat exchange between the hydrogen storage bed and the outside during the hydrogen absorption and desorption process, thereby improving the hydrogen absorption and desorption reaction rate.

[0078] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A metal hydride hydrogen storage system, characterized in that: The hydrogen storage system comprises n hydrogen storage units (1) connected in series, wherein n is 3-20 and is a positive integer; Adjacent hydrogen storage units (1) are connected via a detachable connection unit (3), wherein the detachable connection unit (3) is provided with an opening (5), and the opening (5) is used for the circulation of hydrogen; The hydrogen storage unit (1) comprises a tank body (2), wherein the tank body (2) is filled with a hydrogen storage bed layer, and the hydrogen storage bed layer is used for absorbing / releasing hydrogen and conducting heat.

2. The system according to claim 1, wherein: The n is 3-10, and n is a positive integer.

3. The system according to claim 1 or 2, wherein the height of the tank (2) is 50-600 mm, preferably 50-300 mm; Preferably, the inner diameter of the tank body (2) is 10-100 mm, more preferably 20-50 mm.

4. The system according to any one of claims 1 to 3, wherein: The detachable connection unit (3) comprises a disc detachably connected to the tank body (2), and the opening (5) is formed on the disc; Preferably, the ratio of the opening area of ​​the opening (5) to the area of ​​the disk is 0.02-0.15:1, preferably 0.04-0.1:1; Preferably, the diameter of the opening (5) is 3-20 mm, more preferably 5-15 mm; Preferably, the ratio of the distance between the center of the disk and the center of the opening (5) to the diameter of the disk is 0.25-0.4:1, and more preferably 0.25-0.38:

1.

5. The system according to any one of claims 1 to 4, wherein: Taking the opening (5) on the detachable connection unit (3) at the bottom end of the lowest hydrogen storage unit as a reference, the openings (5) are arranged to rotate in the same direction by 90-180 degrees, preferably 140-180 degrees, in sequence from bottom to top along the axial direction of the tank body (2).

6. The hydrogen storage system according to any one of claims 1 to 5, wherein: The ratio of the height of the hydrogen storage bed to the height of the tank body (2) is 0.7-0.95:1, preferably 0.8-0.95:1; Preferably, the hydrogen storage bed layer comprises a hydrogen storage press sheet and a heat conductive press sheet. Further preferably, the hydrogen storage bed layer is formed by stacking the hydrogen storage press sheet and the heat conductive press sheet. Preferably, the filling height of the hydrogen storage tablet is 5-50 mm, more preferably 5-20 mm; Preferably, the filling height of the heat-conducting pressing sheet is 1-10 mm, more preferably 1-6 mm; Preferably, the hydrogen storage pressed sheet comprises a hydrogen storage alloy and a heat conductive material, and in the hydrogen storage pressed sheet, the mass ratio of the hydrogen storage alloy to the heat conductive material is 1:0.01-0.

2.

7. The system according to claim 6, wherein: The hydrogen storage alloy is selected from at least one of titanium hydrogen storage alloys, zirconium hydrogen storage alloys, vanadium hydrogen storage alloys and rare earth hydrogen storage alloys; Preferably, the thermally conductive material is selected from at least one of expanded graphite, thermally conductive fibers, graphite sheets, carbon nanotubes, aluminum powder, copper powder, titanium powder, foamed aluminum, foamed nickel, and foamed copper; Preferably, the material of the thermally conductive pressing sheet is selected from at least one of expanded graphite, thermally conductive fiber, graphite sheet, carbon nanotube, aluminum powder, copper powder, titanium powder, foamed aluminum, foamed nickel and foamed copper.

8. The system according to any one of claims 1 to 7, wherein: The system further comprises an air pipe (6) in communication with the hydrogen storage unit (1), wherein the air pipe (6) is used to introduce hydrogen into the hydrogen storage unit (1) or release hydrogen in the hydrogen storage unit (1); Preferably, a filter (7) is provided inside the air pipe (6); Preferably, the filter (7) is a copper-based and / or stainless steel-based porous sintered body, preferably a copper-based and / or stainless steel-based porous sintered body sintered by a powder metallurgy method; Preferably, the filter (7) has a precision of 0.5-2 μm.

9. A method for absorbing and releasing hydrogen, wherein: The method comprises: Hydrogen absorption reaction: hydrogen is introduced into the hydrogen storage system, and the hydrogen absorbs hydrogen with the hydrogen storage bed inside the hydrogen storage system, and the first heat transfer medium is used to absorb the heat generated by the hydrogen absorption reaction; Hydrogen desorption reaction: the hydrogen storage bed layer adsorbing hydrogen undergoes a hydrogen desorption reaction, and the second heat transfer medium is used to provide the heat required for the hydrogen desorption reaction; The hydrogen absorption reaction and hydrogen release reaction are carried out in the metal hydride hydrogen storage system according to any one of claims 1 to 8.

10. The method according to claim 9, wherein: The first heat-conducting medium and the second heat-conducting medium are each independently air and / or water vapor; Preferably, the conditions for the hydrogen absorption reaction include: a temperature of 10-50°C, a pressure of 0.5-50MPa, and a temperature of the first heat-conducting medium of 10-50°C; Preferably, the conditions for the hydrogen release reaction include: a temperature of 30-100°C, a pressure of 0.1-50 MPa, and a temperature of the second heat transfer medium of 30-100°C.

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