Hydrogen production system and method using solid-state hydrogen storage material with self-circulation function

Abstract

The application discloses a controllable hydrogen production system and method of solid-state hydrogen storage material with self-circulation function. The method comprises the following steps: loading solid-state hydrogen storage material into a reaction bin, and injecting reaction water into a constant-pressure water bin; by controlling the pressure difference between the reaction bin and the constant-pressure water bin, water is allowed to enter the reaction bin to react with the solid-state hydrogen storage material to generate hydrogen; during the reaction, the reaction liquid and by-products in the reaction bin are transported to the constant-pressure water bin through a circulation system, and the water in the constant-pressure water bin is re-input into the reaction bin, so that the dynamic balance of the by-product concentration and heat is realized; and the generated hydrogen is purified and output to a hydrogen-consuming end. The application can realize water migration and reaction rate adjustment without external intervention.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen production technology, specifically relating to a controllable hydrolysis hydrogen production system and method using a solid hydrogen storage material with self-circulation function. Background Technology

[0002] With the rapid development of the hydrogen energy industry, solid-state hydrogen storage materials have become an important technological direction for large-scale hydrogen storage and transportation due to their advantages such as high energy density, good safety, and convenient storage and transportation. Among them, the water electrolysis hydrogen production technology of solid-state hydrogen storage materials, such as lithium hydride and sodium hydride, can react with water at room temperature and pressure to rapidly release high-purity hydrogen. Compared with thermal hydrogen decomposition, it has the characteristics of milder reaction conditions, simpler system structure, and higher energy density, making it particularly suitable for mobile or distributed hydrogen supply scenarios such as fuel cells.

[0003] Researchers have conducted in-depth studies on existing solid-state hydrogen storage materials for hydrogen production through water electrolysis. However, highly reactive metal hydrides, such as lithium hydride, react violently with water, resulting in an excessively fast hydrogen release rate, which is difficult to match the stable requirements of hydrogen-using devices such as fuel cells. Furthermore, the concentrated heat release from the water electrolysis reaction may trigger side reactions such as spontaneous combustion of hydrogen due to localized temperature rises. Existing technologies often rely on external heat dissipation, which increases the complexity of the system.

[0004] Currently, some methods control the hydrogen release rate by limiting the size of the vent or by staged feeding, but these methods cannot achieve dynamic adjustment and are difficult to solve the problem of byproduct coating. Other methods use catalysts or acidic solutions to promote the reaction, but these introduce additional chemical reagents, reducing the purity and safety of the hydrogen. In addition, existing systems rely solely on diffusion to transfer the reaction liquid and byproducts, resulting in excessively high local concentrations in the reaction tank. This necessitates a significant increase in water volume to dilute the byproducts, limiting the miniaturization and energy efficiency improvement of the system.

[0005] Therefore, there is an urgent need to develop a self-circulating, adaptive solid-state hydrogen storage material hydrolysis hydrogen production system and method that can achieve controllable reaction rate, dynamic balance of by-products, and efficient heat management without external intervention, thereby meeting the demand for stable hydrogen supply in applications such as fuel cells. Summary of the Invention

[0006] To overcome the above problems, this invention develops a controllable water electrolysis hydrogen production system and method using solid hydrogen storage materials with self-circulation function.

[0007] Specifically, the object of the present invention is to provide the following aspects:

[0008] In a first aspect, a method for producing hydrogen by water electrolysis is provided, the method comprising:

[0009] Step 1: Load solid hydrogen storage material into the reaction tank and inject reaction water into the constant pressure water tank;

[0010] Step 2: By controlling the pressure difference between the reaction tank and the constant pressure water tank, water enters the reaction tank and reacts with the solid hydrogen storage material to generate hydrogen.

[0011] During the reaction, the reaction liquid and by-products in the reaction tank are transported to the constant pressure water tank through the circulation system, while the water in the constant pressure water tank is reintroduced into the reaction tank to achieve a dynamic balance between the concentration of by-products and heat.

[0012] Step 3: The hydrogen gas generated by the reaction is purified and output to the hydrogen-using end.

[0013] Secondly, a controllable water electrolysis hydrogen production system using a solid hydrogen storage material with self-circulation function is provided, the system comprising:

[0014] The reaction silo is used to store solid hydrogen storage materials and to carry out the hydrolysis hydrogen production reaction;

[0015] A constant-pressure water tank, connected to the reaction material tank, is used to store reaction water and maintain pressure balance during the hydrolysis reaction process;

[0016] The circulation system connects the reaction tank and the constant pressure water tank, and is used to achieve a dynamic balance between the concentration of by-products and heat.

[0017] A purification system, used to purify the hydrogen gas produced in the reaction;

[0018] The reaction material tank and the constant pressure water tank are driven by a pressure difference to achieve automatic water replenishment and circulation.

[0019] The beneficial effects of this invention include:

[0020] (1) The hydrolysis hydrogen production method provided by the present invention, during the reaction process, the reaction liquid and by-products in the reaction tank are transported to the constant pressure water tank through the circulation system, and the water in the constant pressure water tank is re-input into the reaction tank to achieve dynamic balance between by-product concentration and heat. This process can achieve water migration and reaction rate regulation without external intervention.

[0021] (2) The hydrogen production method by hydrolysis provided by the present invention allows for the recycling of water in the constant pressure water tank, and the total water consumption is only 10 to 25 times the mass of the hydrogen storage material, resulting in high water resource utilization.

[0022] (3) The solid hydrogen storage material controllable water electrolysis hydrogen production system with self-circulation function provided by the present invention relies only on solenoid valves and check valves for control, has a low failure rate, and is suitable for long-term operation. Attached Figure Description

[0023] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0024] In the attached diagram:

[0025] Figure 1 A schematic diagram of a controllable hydrolysis hydrogen production system with self-circulating solid hydrogen storage material according to a preferred embodiment of the present invention is shown.

[0026] Figure 2 The hydrogen release curves of Examples 1 and 2 are shown;

[0027] Figure 3 The graph shows a comparison of the hydrogen release flow rate and the hydrogen temperature discharged from the reaction tank for Examples 1 and 3. Detailed Implementation

[0028] The following will refer to the appendix. Figures 1 to 3 Specific embodiments of the invention will be described in more detail below. While specific embodiments of the invention are shown in the accompanying drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0029] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0030] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the operating state of this invention, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0032] On one hand, according to a method for producing hydrogen by hydrolysis provided by the present invention, the method includes:

[0033] Step 1: Load solid hydrogen storage material into reaction tank 1 and inject reaction water into constant pressure water tank 12;

[0034] Step 2: By controlling the pressure difference between the reaction tank 1 and the constant pressure water tank 12, water enters the reaction tank 1 and reacts with the solid hydrogen storage material to generate hydrogen.

[0035] During the reaction, the reaction liquid and by-products in the reaction silo 1 are transported to the constant pressure water silo 12 through the circulation system, while the water in the constant pressure water silo 12 is reintroduced into the reaction silo 1 to achieve a dynamic balance between the concentration of by-products and heat.

[0036] Step 3: The hydrogen gas generated by the reaction is purified and output to the hydrogen-using end.

[0037] The above-mentioned method for producing hydrogen by hydrolysis is described in detail below.

[0038] Step 1: Load solid hydrogen storage material into reaction tank 1 and inject reaction water into constant pressure water tank 12.

[0039] In step 1, the reaction tank 1 is used to store solid hydrogen storage materials and to carry out the hydrolysis hydrogen production reaction; the constant pressure water tank 12 is used to store reaction water and maintain pressure balance during the hydrolysis reaction process.

[0040] In step 1, the reaction silo 1 is provided with a porous mesh plate 3, which divides the reaction silo 1 into upper and lower layers. The upper material area is used to place and store solid hydrogen storage materials and to carry out hydrolysis reactions, while the lower buffer area is used for gas-liquid buffering during the hydrolysis reaction.

[0041] Furthermore, the pore size of the porous mesh plate 3 is generally 3~5mm to allow the reaction liquid to flow smoothly through the porous mesh plate. Since the hydrolysis reaction generates alkaline byproducts and releases a large amount of gas and heat, especially at the reaction interface between the reactants and water, the temperature can reach over 300℃. To cope with pressure, high temperature, and alkaline corrosion, the material used should be 304 stainless steel or other high-temperature and corrosion-resistant materials, preferably 304 stainless steel.

[0042] In step 1, before the reaction, the lower buffer zone of the porous mesh plate 3 is adjusted to occupy 5% to 10% of the total volume of the reaction silo 1. The volume ratio of the lower buffer zone is adjusted by adjusting the vertical position of the porous mesh plate 3.

[0043] The lower buffer zone balances the rapid hydrogen production reaction with pressure fluctuations. Insufficient volume leads to inadequate buffering, forcing gas from reaction chamber 1 into the constant-pressure water chamber 12, disrupting the pressure balance between the two chambers, causing the pressure in the constant-pressure water chamber 12 to rise continuously, resulting in a runaway reaction. Excessive volume reduces the loading capacity of solid hydrogen storage material, lowering the overall energy density of the system. Secondly, the lower space needs to accommodate the rapidly generated hydrogen gas and splashing droplets / byproducts in the initial stage of the reaction. A volume of 5% to 10% effectively buffers the initial reaction impact, preventing solid byproducts from clogging the mesh, while avoiding excessively long diffusion paths for byproducts due to excessive space. In particular, a 5% to 10% volume allows for hydrogen production rate regulation: when the load decreases, the increased pressure causes water to quickly flow back into the constant-pressure water chamber 12, and the 5% to 10% buffer space ensures that the solid hydrogen storage material can detach from the water surface in time; when the load increases, the same proportion of space allows sufficient water to quickly flow back to contact the material.

[0044] In step 1, reaction water is injected into the constant pressure water tank 12, and the amount of water added is 10 to 25 times the mass of the solid hydrogen storage material.

[0045] When lithium hydride is used as the solid hydrogen storage material, the volume of the reaction water is preferably 24-25 times (ml / g) of the mass of the solid hydrogen storage material, with 25 times being optimal. In unsaturated reaction solutions, lithium hydroxide, a hydrolysis byproduct of lithium hydride, dissolves in the water; when the reaction solution is saturated, sodium hydroxide and sodium tetrahydroxyaluminate, hydrolysis byproducts, deposit on the surface of sodium aluminum hydride, hindering the hydrogen release reaction and slowing it down. To ensure complete dissolution of byproducts, the theoretical minimum water consumption for lithium hydride hydrolysis is at least 24 times the mass of the solid hydrogen storage material. Considering heat and system structure limitations, a practical water consumption of 24-25 times is preferable.

[0046] When the solid hydrogen storage material is sodium aluminum hydride, the hydrolysis products of sodium aluminum hydride are sodium hydroxide, aluminum hydroxide, and sodium tetrahydroxyaluminate. Aluminum hydroxide is essentially insoluble and remains inside the porous rod, while sodium hydroxide and sodium tetrahydroxyaluminate dissolve in water. When the reaction solution is saturated, the hydrolysis byproducts sodium hydroxide and sodium tetrahydroxyaluminate deposit on the surface of sodium aluminum hydride, hindering the hydrogen release reaction and slowing it down. To ensure complete dissolution of the byproducts, the theoretical minimum water consumption for the hydrolysis of sodium aluminum hydride to produce hydrogen is more than 6 times the mass of the solid hydrogen storage material. Considering heat and system structure limitations, an actual water consumption of 10 to 20 times is preferable. In step 1, the solid hydrogen storage material is placed inside the porous rod 2, which helps to block the gas-water channels in the silo with reaction byproducts, ensuring the normal progress of the reaction. At least one porous rod 2 is used, selected according to the power and reaction time.

[0047] In this invention, the system is adapted to stable operation at constant power for fuel cells ranging from 300W to 5kW. Under 1 hour of operation, the required solid hydrogen storage material is 90g to 2550g. When lithium hydride is used as the solid hydrogen storage material, 90g of material is required for 1 hour of operation at 300W, and 1.5kg of material is required for 1 hour of operation at 5kW. When sodium aluminum hydride is used as the solid hydrogen storage material, 2.55kg of material is required for 1 hour of operation at 5kW.

[0048] In step 1, the solid hydrogen storage material can be in block, granular or even powder form; from the perspective of safety (powdered materials have high reactivity and are at risk of spontaneous combustion), ease of processing and yield (large materials are difficult to process and the resulting fine particles will cause waste), preferably, the diameter of the solid hydrogen storage material is 2~15 mm to achieve safe and controllable hydrogen release.

[0049] In step 1, the solid hydrogen storage material may be one or a mixture of several of lithium hydride, lithium aluminum hydride, sodium aluminum hydride, sodium hydride, and calcium hydride, preferably lithium hydride and / or sodium aluminum hydride.

[0050] Among them, lithium hydride has a theoretical hydrogen storage density of up to 12.6 wt%, which is one of the materials with the highest mass hydrogen storage density among known metal hydrides. Sodium aluminum hydride has a slightly lower hydrogen storage density, but its raw material cost is lower, which is conducive to large-scale application. Secondly, lithium hydride and sodium aluminum hydride can undergo a violent exothermic reaction with pure water at room temperature, and can be started up quickly without additional catalysts or acidic solutions.

[0051] Furthermore, the porous rod 2 has a pore size of 50-80 mesh, such as 60 mesh, to prevent the solid hydrogen storage material from leaking out and to prevent reaction byproducts from clogging the gas-water channels in the silo, thus ensuring the normal progress of the reaction.

[0052] In a preferred embodiment, such as Figure 1As shown, the top of the reaction tank 1 is equipped with a first pressure transmitter 14, which is used to collect the gas phase pressure inside the reaction tank 1; the top is also equipped with a second solenoid valve 5, which is used to output hydrogen to the purification unit; the top is also equipped with a third solenoid valve 6, which connects the gas phase space of the reaction tank 1 and the constant pressure water tank 12; the bottom is equipped with a first solenoid valve 4, which is used to discharge waste liquid; the bottom is also equipped with a pipe that is connected in sequence to a fourth solenoid valve 7 and a first check valve 16, which is connected to the bottom of the constant pressure water tank 12. This pipe is used to control the liquid connection between the reaction tank 1 and the constant pressure water tank 12, so as to realize water migration and reaction rate regulation; the bottom is also equipped with a second check valve 17 connected to the upper end of the water level of the constant pressure water tank 12.

[0053] Furthermore, the constant pressure water tank 12 is a sealed pressure-resistant container. Its top is connected to the top of the reaction tank 1 via a third solenoid valve 6 to achieve air pressure balance; its bottom is connected to the bottom of the reaction tank 1 via a fourth solenoid valve 7 to achieve water migration driven by pressure difference; a second pressure transmitter 15 is also provided at the top to monitor the pressure inside the constant pressure water tank 12 in real time; a water inlet is also provided at the top to connect to an external water source via a fifth solenoid valve 9.

[0054] In step 1, using Figure 1 When the system shown performs hydrogen production via hydrolysis, before the reaction, porous rods 2 containing solid hydrogen storage material are placed in the upper material zone of the reaction silo 1. The position of the porous mesh plate 3 is adjusted according to the hydrolysis characteristics of the selected solid hydrogen storage material, so that the lower buffer zone occupies 5% to 10% of the total volume of the reaction silo 1. Water is then injected into the constant-pressure water tank 12 via the fifth solenoid valve 9. When 10 to 25 times the mass of the solid hydrogen storage material is injected into the constant-pressure water tank 12, the fifth solenoid valve 9 and the sixth solenoid valve 10 are opened. After adding water, the fifth solenoid valve 9 and the sixth solenoid valve 10 are closed.

[0055] In step 1, upon startup, the fourth solenoid valve 7 and the second solenoid valve 5 are opened, allowing water to enter the reaction chamber 1 and trigger the reaction. Specifically: the fourth solenoid valve 7 and the second solenoid valve 5 are opened, at which point water in the constant pressure water chamber 12 flows into the lower buffer zone of the reaction chamber 1 through the fourth solenoid valve 7, and permeates to the upper material zone through the porous mesh plate 3, where it comes into contact with the solid hydrogen storage material in the porous material rod 2 and undergoes a hydrolysis reaction to produce hydrogen. The hydrogen enters the purification system through the second solenoid valve 5 (passing sequentially through the water washing tank 8 and the gas-water separator 13), and then is output to the hydrogen-using end, such as a fuel cell, through the electro-proportional valve 11 for pressure regulation.

[0056] In step 1, during the initial startup phase, the third solenoid valve 6 is open, maintaining a gas-phase pressure balance between the reaction chamber 1 and the constant-pressure water chamber 12. As the reaction proceeds, the pressure in the constant-pressure water chamber 12 rises. When the second pressure transmitter 15 detects that the pressure reaches 100 kPa, the sixth solenoid valve 10 is opened to release pressure. When the pressure in the constant-pressure water chamber 12 reaches 80-90 kPa again, the third solenoid valve 6 and the sixth solenoid valve 10 are closed. At this point, the reaction system enters normal operation, and the gas connection between the reaction chamber 1 and the constant-pressure water chamber 12 is cut off, but the fourth solenoid valve 7 remains open.

[0057] Step 2: By controlling the pressure difference between the reaction tank 1 and the constant pressure water tank 12, water enters the reaction tank 1 and reacts with the solid hydrogen storage material to generate hydrogen.

[0058] In step 2, the reaction chamber 1, the constant pressure water chamber 12, the first one-way valve 16, the second one-way valve 17, and the fourth solenoid valve 7 constitute a self-circulating system. This self-circulating system drives the directional flow of liquid through pressure fluctuations, achieving a dynamic balance between reactants, heat, and byproducts. This prevents excessively high byproduct concentrations in the reaction chamber 1, which could hinder the reaction; and also prevents excessively high temperatures in the reaction chamber 1, which could increase the water vapor content in the gas, thus increasing the heat dissipation and dehydration pressure of the purification system. Specifically:

[0059] When the hydrogen end load decreases, the pressure inside the reaction tank 1 increases, pushing the excess high-temperature liquid and by-products in the reaction tank 1 through the second one-way valve 17 to the constant pressure water tank 12, reducing the contact area between the porous rod 2 and water, and reducing the hydrogen production rate; at the same time, it mixes with the low-temperature liquid in the constant pressure water tank 12 to achieve a dynamic balance of heat and by-products.

[0060] When the hydrogen load increases, the pressure inside the reaction chamber 1 decreases. The low-temperature water from the constant-pressure water chamber 12 enters the lower buffer zone of the reaction chamber 1 through the first one-way valve 16 and the fourth solenoid valve 7 to replenish the reaction interface of the porous rod 2. The solid hydrogen storage material in the porous rod 2 is wetted by the porous mesh plate 3, which increases the hydrogen production rate. At the same time, it mixes with the residual high-temperature liquid and by-products in the reaction chamber 1, reducing the water temperature and by-product concentration in the reaction chamber, and achieving a dynamic balance of heat and by-products.

[0061] In the aforementioned self-circulation process, water from the constant pressure water tank 12, under negative pressure, enters the lower buffer zone of the reaction tank 1 through the first one-way valve 16 and the fourth solenoid valve 7, and then wets the solid hydrogen storage material in the porous rod 2 through the porous mesh plate 3 to maintain the water volume required for the hydrolysis reaction. The by-products generated by the reaction are returned to the constant pressure water tank 12 through the second one-way valve 17 under the positive pressure of the reaction tank 1, thereby achieving by-product dilution and heat diffusion.

[0062] In step 2, the hydrolysis reaction can also be stopped and restarted by the second solenoid valve 5: during the reaction, the second solenoid valve 5 is closed, the pressure in the reaction silo 1 increases, the water inside is forced into the constant pressure water silo 12, the porous rod 2 is separated from the water, and the reaction stops; after the second solenoid valve 5 is opened, the reaction water re-enters the reaction silo 1, and the reaction continues.

[0063] Step 3: The hydrogen gas generated by the reaction is purified and output to the hydrogen-using end.

[0064] In step 3, the hydrogen generated by the reaction is purified by a purification system and then output to the hydrogen-using end.

[0065] Furthermore, the purification system includes:

[0066] Water washing tank 8 is used for bubbling and washing the hydrogen produced by the hydrolysis hydrogen production reaction.

[0067] Gas-water separator 13 is used to dry the hydrogen gas after bubbling washing.

[0068] In step 3, the washing tank 8 contains water, and the reaction silo 1 is connected to the water at the bottom of the washing tank 8 through a pipe connected to the second solenoid valve 5.

[0069] Furthermore, the top of the water washing tank 8 is provided with a pipeline connected to the gas-water separator 13, so that the hydrogen produced by the hydrolysis hydrogen production reaction is directly introduced into the gas-water separator 13 for drying after being washed with water.

[0070] In step 3, the gas-water separator 13 is filled with a desiccant. The desiccant can completely fill the gas-water separator 13 or partially fill it. However, during this process, it must be ensured that the pipelines of the water washing tank 8 and the gas-water separator 13 are directly inserted into the desiccant to ensure the purity of the hydrogen used.

[0071] In step 3, the hydrogen produced by the hydrolysis hydrogen production reaction (containing a small amount of water vapor and possibly carrying solid particles) is introduced into the water at the bottom of the water washing tank 8 through the pipe connected to the second solenoid valve 5 of the reaction tank 1. At this time, the hydrogen rises from the water in the form of bubbles. When the bubbles rise through the water layer, the heavier solid particles carried in the bubbles will be captured, settled or dissolved in the water. Some water vapor may also be cooled or dissolved in the water during the rising of the bubbles. In addition, since hydrogen itself is insoluble in water, after the bubbles burst, the purified hydrogen (which may still contain water vapor) will escape from the top of the water washing tank 8 to the gas-water separator 13. The liquid water droplets are further removed by the desiccant material to obtain drier hydrogen, which is then supplied to the hydrogen-using end such as a fuel cell.

[0072] In step 3, the top of the gas-water separator 13 is equipped with a hydrogen delivery pipeline. One of the hydrogen delivery pipelines is equipped with a sixth solenoid valve 10, and the other is equipped with an electric proportional valve 11. The sixth solenoid valve 10 is used to release pressure, and the electric proportional valve 11 is used to stabilize and adjust the hydrogen pressure to the pressure required by the fuel cell before outputting it.

[0073] In step 3, with sufficient reactants, the pressure in reaction chamber 1 should fluctuate around 80 kPa. If it is below 50 kPa, it indicates that the reactants have reacted completely. At the same time, after passing through the electro-proportional valve 11, the pressure will drop to around 40 kPa, which is lower than the operating pressure of the fuel cell, and the reaction needs to be stopped. Therefore, when the first pressure transmitter 14 detects that the pressure in reaction chamber 1 is below 45-50 kPa, such as 50 kPa, the reaction ends, the third solenoid valve 6 is opened to balance the pressure in the two chambers, and then the sixth solenoid valve 10 is opened to release pressure.

[0074] In step 3, when the reaction is complete, the first solenoid valve 4 at the bottom of the reaction silo 1 is opened to discharge the reaction waste liquid.

[0075] Secondly, according to the present invention, a controllable water electrolysis hydrogen production system with a self-circulating solid hydrogen storage material is provided, the system comprising:

[0076] Reaction silo 1 is used to store solid hydrogen storage materials and to carry out hydrolysis hydrogen production reactions;

[0077] The constant pressure water tank 12 is used to store reaction water and maintain pressure balance during the hydrolysis reaction process;

[0078] A circulation system used to achieve a dynamic balance between byproduct concentration and heat;

[0079] A purification system is used to purify the hydrogen gas produced in the reaction.

[0080] The present invention is further described below through specific examples; however, these examples are merely exemplary and do not constitute any limitation on the scope of protection of the present invention.

[0081] Example 1

[0082] Feeding: Place two porous rods 2 (60 mesh) containing 15 mm 150 g lithium hydride into the upper material zone of the reaction silo 1; adjust the position of the porous mesh plate 3 (304 stainless steel, 3 mm mesh) so that the lower buffer zone occupies 10% of the total volume of the reaction silo 1; open the fifth solenoid valve 9 and the sixth solenoid valve 10; add 7.5 L of water through the fifth solenoid valve 9; and close the fifth solenoid valve 9 and the sixth solenoid valve 10.

[0083] Start-up: Open the fourth solenoid valve 7 and the second solenoid valve 5. Water enters the reaction tank 1 from the constant pressure water tank 12 and reacts with the material in the porous material bar 2 to release hydrogen. The pressure in the constant pressure water tank 12 rises. When the pressure of the second pressure transmitter 15 reaches 100 kPa, open the sixth solenoid valve 10 to release pressure. When the pressure of the second pressure transmitter 15 reaches 80 kPa again, close the sixth solenoid valve 10 and the third solenoid valve 6. At this time, the entire system is in normal operation. The pressure fluctuation range of the second pressure transmitter 15 is 80 ± 10 kPa. The generated hydrogen passes through the second solenoid valve 5 in sequence through the water washing tank 8 and the gas-water separator 13. After being kept at a constant pressure of 50 kPa by the electro-proportional valve 11, it is output. A flow regulating valve is used to simulate the hydrogen consumption of a 1 kW fuel cell stack, and the real-time hydrogen release flow rate is recorded by a mass flow meter. The real-time temperature of the hydrogen downstream of the second solenoid valve 5 is recorded by a temperature sensor.

[0084] End: The reaction ends when the pressure of the first pressure transmitter 14 is less than 50 kPa. Open the third solenoid valve 6 to balance the pressure in the two chambers, then open the sixth solenoid valve 10 to release pressure, and then open the first solenoid valve 4 at the bottom of the reaction silo 1 to discharge the waste liquid. Remove the hollow porous material rod 2 from the reaction silo 1.

[0085] Example 2

[0086] Feeding: Place two porous material rods 2 (60 mesh) containing 2mm 250g sodium aluminum hydride into the upper material zone of reaction silo 1; adjust the position of the porous mesh plate 3 (304 stainless steel, 3mm mesh) so that the lower buffer zone occupies 10% of the total volume of reaction silo 1; open the fifth solenoid valve 9 and the sixth solenoid valve 10; add 5L of water through the fifth solenoid valve 9; and close the fifth solenoid valve 9 and the sixth solenoid valve 10.

[0087] Start-up: Open the fourth solenoid valve 7 and the second solenoid valve 5. Water enters the reaction tank 1 from the constant pressure water tank 12 and reacts with the material in the porous material bar 2 to release hydrogen. The pressure in the constant pressure water tank 12 rises. When the pressure of the second pressure transmitter 15 reaches 100 kPa, open the sixth solenoid valve 10 to release pressure. When the pressure of the second pressure transmitter 15 reaches 80 kPa again, close the sixth solenoid valve 10 and the third solenoid valve 6. At this time, the entire system is in normal operation. The pressure fluctuation range of the second pressure transmitter 15 is 80 ± 10 kPa. The generated hydrogen passes through the second solenoid valve 5 in sequence through the water washing tank 8 and the gas-water separator 13. After being kept at a constant pressure of 50 kPa by the electro-proportional valve 11, it is output. A flow regulating valve is used to simulate the hydrogen consumption of a 1 kW fuel cell stack, and the real-time hydrogen release flow rate is recorded by a mass flow meter.

[0088] End: The reaction ends when the pressure of the first pressure transmitter 14 is less than 50 kPa. Open the third solenoid valve 6 to balance the pressure in the two chambers, then open the sixth solenoid valve 10 to release pressure, and then open the first solenoid valve 4 at the bottom of the reaction silo 1 to discharge the waste liquid. Remove the hollow porous material rod 2 from the reaction silo 1.

[0089] Figure 2 The hydrogen release curves of Examples 1 and 2 are shown. It can be seen that the hydrogen release curve of the sodium aluminum hydride solid hydrogen storage material in this system fluctuates more significantly than that of lithium hydride. This is because sodium aluminum hydride has higher hydrolysis reactivity and a faster hydrogen release rate. Overall, both solid hydrogen storage materials can provide a stable flow rate, which is consistently maintained at 13 L / min, sufficient for approximately 1 hour of constant power operation of a 1 kW fuel cell. Since the production cost of sodium aluminum hydride is only one-tenth that of lithium hydride under the same hydrogen production conditions, sodium aluminum hydride is more suitable as the solid hydrogen storage material for this system from a cost perspective.

[0090] Example 3

[0091] Remove the first check valve 16 and the second check valve 17 from the system, and close the pipeline where the second check valve 17 is located. At this time, there is no self-circulation system.

[0092] Feeding: Place two porous rods 2 (60 mesh) containing 15 mm 150 g lithium hydride into the upper material zone of the reaction silo 1; adjust the position of the porous mesh plate 3 (304 stainless steel, 3 mm mesh) so that the lower buffer zone occupies 10% of the total volume of the reaction silo 1; open the fifth solenoid valve 9 and the sixth solenoid valve 10; add 5 L of water through the fifth solenoid valve 9; and close the fifth solenoid valve 9 and the sixth solenoid valve 10.

[0093] Start-up: Open the fourth solenoid valve 7 and the second solenoid valve 5. Water enters the reaction tank 1 from the constant pressure water tank 12 and reacts with the material in the porous material bar 2 to release hydrogen. The pressure in the constant pressure water tank 12 rises. When the pressure of the second pressure transmitter 15 reaches 100 kPa, open the sixth solenoid valve 10 to release pressure. When the pressure of the second pressure transmitter 15 reaches 80 kPa again, close the sixth solenoid valve 10 and the third solenoid valve 6. At this time, the entire system is in normal operation. The pressure fluctuation range of the second pressure transmitter 15 is 80 ± 10 kPa. The generated hydrogen passes through the second solenoid valve 5 in sequence through the water washing tank 8 and the gas-water separator 13. After being kept at a constant pressure of 50 kPa by the electro-proportional valve 11, it is output. A flow regulating valve is used to simulate the hydrogen consumption of a 1 kW fuel cell stack, and the real-time hydrogen release flow rate is recorded by a mass flow meter.

[0094] End: The reaction ends when the pressure of the first pressure transmitter 14 is less than 50 kPa. Open the third solenoid valve 6 to balance the pressure in the two chambers, then open the sixth solenoid valve 10 to release pressure, and then open the first solenoid valve 4 at the bottom of the reaction silo 1 to discharge the waste liquid. Remove the hollow porous material rod 2 from the reaction silo 1.

[0095] Figure 3 The diagram shows a comparison of the hydrogen release flow rate and the hydrogen temperature discharged from reaction silo 1 for Examples 1 and 3. Using lithium hydride solid-state hydrogen storage material, under the same 25 times water concentration, the system in Example 1, due to its circulation system, exhibited a more stable flow rate and no tailing in the later stages of hydrogen release. The system maintained a stable hydrogen release flow rate of approximately 13 L / min for 60 minutes, decreasing to 0 after 3 minutes, indicating the end of the reaction. In Example 3, however, the removal of the self-circulation system resulted in a flow rate decrease in the later stages of hydrogen release, a significant tailing phenomenon, and a marked reduction in the total hydrogen release. The system maintained a stable hydrogen release flow rate of approximately 13 L / min for only 27 minutes, decreasing to 0 after 10 minutes, indicating the end of the reaction. This is because the concentration of lithium hydroxide byproducts in the solution continuously increases as hydrogen release proceeds.

[0096] It is evident from the above that, with a self-circulating system, during the hydrolysis reaction, the byproducts and heat generated in reaction chamber 1 form a high-concentration hydrothermal liquid with the liquid within. Driven by pressure fluctuations, this hydrothermal liquid flows through the second one-way valve 17 into the constant-pressure water chamber 12, where it mixes with and dilutes the liquid, thus cooling it down. The liquid in the constant-pressure water chamber 12 then enters reaction chamber 1 through the first one-way valve 16 to replenish water, forming a self-circulation and achieving overall heat and byproduct balance within the system. Without a circulation system, the byproducts in the reaction chamber can only partially return to the constant-pressure water chamber 12 through the fourth solenoid valve 7 when the pressure in reaction chamber 1 is high. This prevents the byproducts from diffusing into the entire solution system in a timely manner, resulting in supersaturation of byproduct concentration in reaction chamber 1. The byproducts precipitate and coat the surface of lithium hydride, hindering the smooth progress of the hydrogen release reaction. Furthermore, the heat in the reaction chamber is balanced through the self-circulation system, and the temperature of the gas discharged from the second solenoid valve 5 is lower than the hydrogen temperature in the system without a circulation system, reducing the cooling and dehydration pressure on the downstream purification system. Therefore, the system uses less water and has a smaller volume.

[0097] The present invention has been described in detail above with reference to preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments are merely illustrative explanations of the invention and do not constitute any limitation on the scope of protection of the invention. Various improvements, equivalent substitutions, or modifications can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of protection of the invention, and all such modifications fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for hydrogen production by hydrolysis, characterized by, The method includes: Step 1: Load solid hydrogen storage material into the reaction tank (1) and inject reaction water into the constant pressure water tank (12); The reaction silo (1) is provided with a porous mesh plate (3), which divides the reaction silo (1) into upper and lower layers. The upper material area is used to place and store solid hydrogen storage materials and to carry out hydrolysis reactions. The lower buffer zone is used for gas-liquid buffering during hydrolysis reactions. The lower buffer zone accounts for 5% to 10% of the total volume of the reaction silo (1). The pore size of the porous mesh plate (3) is 3 to 5 mm. The solid hydrogen storage material is placed in a porous material rod (2). The pore size of the porous material rod (2) is 50 to 80 mesh, and the diameter of the solid hydrogen storage material is 2 to 15 mm. When the solid hydrogen storage material is lithium hydride, the amount of water injected into the constant pressure water tank (12) is 24 to 25 times the mass of the solid hydrogen storage material; When the solid hydrogen storage material is sodium aluminum hydride, the amount of water injected into the constant pressure water tank (12) is 10 to 20 times the mass of the solid hydrogen storage material; Step 2: By controlling the pressure difference between the reaction tank (1) and the constant pressure water tank (12), water enters the reaction tank (1) and reacts with the solid hydrogen storage material to generate hydrogen. The bottom of the reaction tank (1) is provided with a pipe that is sequentially connected to a fourth solenoid valve (7) and a first check valve (16). This pipe is connected to the bottom of the constant pressure water tank (12). This pipe is used to control the liquid circuit connection between the reaction tank (1) and the constant pressure water tank (12) to realize water migration and reaction rate regulation. The bottom of the reaction tank (1) is also provided with a second check valve (17), which is connected to the upper end of the water level of the constant pressure water tank (12). The top of the reaction tank (1) is also provided with a third solenoid valve (6), which connects the gas phase space of the reaction tank (1) and the constant pressure water tank (12). The reaction tank (1), constant pressure water tank (12), first check valve (16), second check valve (17) and fourth solenoid valve (7) constitute a self-circulating system: When the pressure inside the reaction tank (1) increases, the liquid and by-products inside the reaction tank (1) pass through the second one-way valve (17) to the constant pressure water tank (12). When the pressure inside the reaction silo (1) decreases, water from the constant pressure water silo (12) enters the reaction silo (1) through the first check valve (16) and the fourth solenoid valve (7). During the above reaction process, the reaction liquid and by-products in the reaction tank (1) are transported to the constant pressure water tank (12) through the circulation system, and the water in the constant pressure water tank (12) is re-input into the reaction tank (1) to achieve a dynamic balance between the concentration of by-products and heat. Step 3: The hydrogen gas generated by the reaction is purified and output to the hydrogen-using end.

2. The method of claim 1, wherein, The reaction silo (1) is used to store solid hydrogen storage materials and to carry out hydrolysis hydrogen production reactions.

3. The method according to claim 1, characterized in that, The constant pressure water tank (12) is used to store reaction water and maintain pressure balance during the hydrolysis reaction process.

4. The method of claim 1, wherein, During the reaction, the circulation system drives the liquid to flow in a directional manner through the pressure difference between the reaction material tank (1) and the constant pressure water tank (12), thereby achieving a dynamic balance of reactants, heat and by-products in the system.

5. The method of claim 1, wherein, The reaction ends when the pressure in the reaction silo (1) is below 45~50 kPa.

6. A hydrolysis hydrogen production system for carrying out the method according to any one of claims 1 to 5, characterized in that The system includes: The reaction silo (1) is used to store solid hydrogen storage materials and to carry out hydrolysis hydrogen production reactions; The constant pressure water tank (12) is connected to the reaction material tank (1) and is used to store reaction water and maintain pressure balance during the hydrolysis reaction process; The circulation system connects the reaction material tank (1) and the constant pressure water tank (12), which is used to achieve a dynamic balance between the concentration of by-products and heat. A purification system, used to purify the hydrogen gas produced in the reaction; The reaction material tank (1) and the constant pressure water tank (12) are driven by a pressure difference to achieve automatic water replenishment and circulation.

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