Device and method for preparing hydrogen by hydrolyzing aluminum under alkaline condition

Abstract

The invention discloses a device for preparing hydrogen from aluminum composite powder and sodium hydroxide. The device comprises a hydrogen generator, and a grading reaction tank is arranged in the hydrogen generator; a liquid storage tank and a powder storage tank are arranged above the hydrogen generator; the liquid storage tank and the powder storage tank are respectively connected to the reaction tank through pipelines with one-way valves; the top of the hydrogen generator is connected with a hydrogen buffer tank through a pipeline with a one-way valve; the hydrogen buffer tank is provided with a charging pipe which is connected to an engine and is provided with an electric control one-way valve; and the bottom of the hydrogen generator is connected with the receiving tank through a pipeline with an electric controllable valve. The device is simple in overall structure and small in size, specifically, devices with different sizes can be prepared according to the volume of an engine, replacement and maintenance are easy, the cost of raw materials needed by the hydrogen production process is low, the theoretical hydrogen production amount of aluminum is high, the hydrogen production rate is high and controllable, the hydrogen production efficiency is high, and the dynamic requirement of engine combustion can be met.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, and more specifically to an apparatus and method for producing hydrogen under alkaline conditions. Background Technology

[0002] Hydrogen is an ideal clean energy source, boasting high energy conversion efficiency and zero emissions during use, making it environmentally friendly. Hydrogen's mass-energy equivalence is 143 MJ / kg, approximately three times that of gasoline (46.9 MJ / kg), meaning that hydrogen releases three times the energy of gasoline when consuming the same mass of fuel. Hydrogen also has a wide flammability range; under optimal combustion conditions, the energy required for hydrogen combustion is far lower than that of many common fuels. Despite these advantages, numerous technical challenges remain in hydrogen storage and production, limiting its widespread application as an engine fuel.

[0003] High-pressure gaseous hydrogen storage and cryogenic liquid hydrogen storage are currently commonly used hydrogen storage technologies, but both suffer from low storage and transportation efficiency and safety issues. Currently, hydrogen production typically employs natural gas reforming, water electrolysis, and biosynthesis, but these methods have certain limitations. Natural gas reforming is inefficient and costly, and cannot provide large-scale, real-time hydrogen supply. Water electrolysis has an efficiency of approximately 60%, and although it has been applied to hydrogen fuel cells, this method is limited by battery capacity and electrolysis rate, and it easily generates chemical waste and used batteries during production, burdening the environment. While biosynthesis is low-cost, its hydrogen production rate and scale are also difficult to sustain in a real-time and stable manner. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an apparatus and method for preparing hydrogen by hydrolysis of aluminum under alkaline conditions, thereby achieving efficient preparation of hydrogen without the need for stringent conditions such as high pressure or low temperature liquid storage and transportation. It has the advantages of low raw material cost, environmental protection, and the ability to meet the dynamic combustion requirements of the engine in real time.

[0005] To address the above technical problems, this invention discloses an apparatus for preparing hydrogen gas by hydrolyzing aluminum under alkaline conditions. The apparatus includes a hydrogen generator with a staged reaction tank inside. Above the hydrogen generator are a liquid storage tank and a powder storage tank, each connected to the reaction tank via pipes equipped with a one-way valve (electrically controlled one-way valve or differential pressure one-way valve). The top of the hydrogen generator is connected to a hydrogen buffer tank via a pipe equipped with a one-way valve (electrically controlled one-way valve or differential pressure one-way valve), and the hydrogen buffer tank has a feed pipe with an electrically controlled one-way valve connected to an engine. The bottom of the hydrogen generator is connected to a receiving tank via a pipe equipped with an electrically controllable valve. Each valve is connected to a control system. The one-way valves are used to control the one-way flow of liquid from the liquid storage tank to the reaction tank, the one-way flow of powder from the powder storage tank to the reaction tank, the one-way flow of gas from the hydrogen generator to the hydrogen buffer tank, and the one-way flow of gas from the hydrogen buffer tank to the engine. The hydrogen generator includes a main body and a top cover. The top cover is equipped with a first pressure sensor, a first hydrogen sensor, and a first temperature sensor. The top cover is sealed to the main body using a top cover sealing clip. The hydrogen generator is a cubic or cylindrical steel tank capable of withstanding 2–10 atmospheres of pressure. The hydrogen buffer tank includes a tank body and a lid on top of the tank body. The lid is equipped with a second pressure sensor, a second hydrogen sensor, and a second temperature sensor. The lid is sealed to the tank body using a lid sealing clip. Each pressure sensor, temperature sensor, and hydrogen sensor is connected to an instrument control system, which can detect and regulate the pressure and temperature inside the hydrogen generator and hydrogen buffer tank, as well as detect the purity of the hydrogen.

[0006] Furthermore, the staged reaction tank includes a primary reaction tank, a secondary reaction tank, and a tertiary reaction tank arranged sequentially from top to bottom. These three tanks are fixed inside the hydrogen generator by a fixing rod passing through the center of each tank. The dimensions of the primary, secondary, and tertiary reaction tanks increase sequentially. The secondary and tertiary reaction tanks have a mesh structure (both the bottom and walls of the tanks are mesh structures), which facilitates thorough mixing of the materials. The primary, secondary, and tertiary reaction tanks can be made of ordinary heat-resistant and alkali-resistant stainless steel, plastic, or glass.

[0007] Furthermore, the top of the liquid storage tank is provided with a first vent and a first feed port with a sealing cap; the top of the powder storage tank is provided with a second vent and a second feed port with a sealing cap. Both the first and second vents are filled with a desiccant (alkaline). The vents allow the storage tanks and liquid storage tanks to communicate with the air, maintaining a uniform internal pressure. The desiccant is used to adsorb water vapor and carbon dioxide from the air and to keep dust out.

[0008] Furthermore, a filter is installed on the pipe connecting the hydrogen generator and the hydrogen buffer tank.

[0009] Furthermore, the receiving tank has an air inlet on one side, with an air filter at the inlet, and an air outlet at the top of the receiving tank away from the air inlet. A gravity check valve is installed at the air outlet. An atomizing fan is installed inside the receiving tank, located directly below the outlet of the pipe connecting the hydrogen generator and the receiving tank. The gravity check valve is used to control the unidirectional delivery of the remaining air after carbon dioxide removal from the receiving tank to the external environment.

[0010] Furthermore, the hydrogen generator is equipped with a liquid level sensor; the bottom of the hydrogen buffer tank is equipped with a drain pipe, and a manual drain valve is installed on the drain pipe.

[0011] The present invention also discloses a method for preparing hydrogen using the aforementioned apparatus, comprising the following steps:

[0012] (1) When the engine is started, the fourth electronically controlled check valve opens automatically, and hydrogen is delivered from the hydrogen buffer tank to the engine; as the pressure in the hydrogen buffer tank decreases, the third electronically controlled check valve opens automatically, and hydrogen is delivered from the hydrogen generator to the hydrogen buffer tank; as the pressure in the hydrogen generator decreases, the first and second electronically controlled check valves open automatically, and sodium hydroxide solution and aluminum composite powder are simultaneously added to the primary reaction tank for mixing and reaction. Subsequently, the mixture overflows from the primary reaction tank to the secondary reaction tank, and then passes through the strainers of the secondary and tertiary reaction tanks to reach the hydrogen. At the bottom of the generator, this process continuously produces hydrogen gas. When the level sensor detects that the liquid level of the mixed solution of sodium aluminate and other salts, a reaction byproduct at the bottom of the hydrogen generator, reaches the maximum limit, the electrically controlled valve automatically opens. The mixed solution enters the receiving tank from the bottom of the hydrogen generator and is atomized into water mist by the atomizing fan. Sodium aluminate reacts with carbon dioxide in the air introduced from the air inlet to produce aluminum hydroxide. The remaining air is discharged from the gravity check valve at the air outlet. When the level sensor detects that the liquid level of the mixed solution drops to the minimum limit, the electrically controlled valve automatically closes. Before use, the aluminum composite powder is ball-milled under inert gas protection to obtain micron-sized powder. The mass ratio of grinding balls to powder during ball milling can be 5:1.

[0013] (2) After the engine is turned off, the fourth electronically controlled check valve automatically closes; then, when the pressure in the hydrogen buffer tank reaches the limit pressure, the third electronically controlled check valve automatically closes; finally, when the pressure in the hydrogen generator is lower than the limit pressure but greater than 1 atmosphere, the first and second electronically controlled check valves close simultaneously.

[0014] The receiving tank is opened periodically to collect aluminum hydroxide and other products, or the receiving tank can be replaced directly for centralized collection by the manufacturer.

[0015] The hydrogen generator and hydrogen buffer tank are pre-filled with hydrogen at a specified pressure before hydrogen production (filled before the device leaves the factory), and sufficient sodium hydroxide solution and aluminum composite powder are added to the liquid storage tank and powder storage tank, respectively.

[0016] Furthermore, the concentration of the sodium hydroxide solution is 0.5–5.0 M, and the aluminum composite powder includes aluminum powder and sodium chloride, with a mass ratio of aluminum powder to sodium chloride of 1–6:1. The aluminum powder can be pure aluminum, scrap aluminum, etc.

[0017] Furthermore, the aluminum composite powder also includes one or two of a metal or sodium carbonate. The metal is selected from one or more of magnesium, nickel, iron, calcium, iridium, or tin. The metal acts as a catalyst to increase the reaction rate of hydrogen production. Sodium carbonate is used to prevent the aluminum powder from getting damp, to prevent the aluminum powder from being oxidized into aluminum oxide, and to reduce the corrosive effect on the container.

[0018] Furthermore, when the aluminum composite powder contains metal, the mass ratio of aluminum powder to metal is 1:0.01 to 0.1; when the aluminum composite powder contains sodium carbonate, the mass ratio of aluminum powder to sodium carbonate is 1:0.5 to 1.

[0019] The beneficial effects of this invention are:

[0020] This device has a simple overall structure and small size. It can be manufactured in different sizes to suit different engine sizes, making it easy to replace and maintain. Through a staged reaction tank combined with a specific alkaline aqueous solution and aluminum composite powder, the aluminum composite powder undergoes a full and rapid reaction. Combined with the buffering effect of a hydrogen buffer tank, it can continuously supply fuel to any gas turbine engine. Hydrogen is directly produced in the hydrogen generator through the hydrolysis reaction of aluminum composite powder in an alkaline sodium hydroxide aqueous solution. The produced hydrogen is transported to the hydrogen buffer tank and can be supplied to the engine in real time, eliminating the safety hazards associated with hydrogen storage and transportation in existing technologies.

[0021] This invention uses aluminum composite powder as the reaction raw material, avoiding the problem of excessively fast reaction rate when using single aluminum powder to produce hydrogen. When sodium carbonate is added to the aluminum composite powder, sodium chloride and sodium carbonate can prevent the aluminum powder from getting damp, and sodium carbonate can also prevent the aluminum powder from being oxidized into aluminum oxide, eliminating the need for inert gas protection during the transportation of aluminum powder.

[0022] The hydrogen production process requires low-cost raw materials (sodium chloride and sodium carbonate are used as promoters, which can reduce raw material costs), aluminum has a high theoretical hydrogen production capacity (1 gram of aluminum produces approximately 1.24 liters of hydrogen), the hydrogen production rate is fast and controllable (the hydrogen production rate can be controlled by adjusting the concentration and flow rate of the alkali solution), and the hydrogen production efficiency is high (the synergistic effect of sodium chloride and sodium carbonate can further ensure high reactivity), which can meet the dynamic requirements of engine combustion.

[0023] Besides producing hydrogen gas, the reaction process also generates sodium aluminate (the main byproduct) and other salt solutions such as sodium carbonate and sodium bicarbonate (minor byproducts). This invention uses carbon dioxide carbonization to precipitate aluminum hydroxide from sodium aluminate solution, which not only reduces the carbon dioxide content in the air but also yields high-purity aluminum hydroxide. Aluminum hydroxide can be used as a raw material for flame retardants and water purification agents, and also lays the foundation for the synthesis of high-quality boehmite. Sodium aluminate is also widely used in drinking water and wastewater treatment systems (phosphorus removal) and provides an economical resource for highly active alumina. The other salt solutions of this invention can be recycled and reused, further effectively reducing the cost of hydrogen production.

[0024] Currently, the production cost of hydrogen is approximately 28 yuan / kg, and with storage and transportation costs, it reaches about 48.6 yuan / kg, making the final cost far higher than that of gasoline and diesel. The comprehensive cost of green hydrogen proposed in this invention can be reduced to 15 yuan / kg.

[0025] Furthermore, the engine uses hydrogen as fuel for combustion, and its only emission is water, with no other chemical pollutants, making it environmentally friendly. Existing technologies for hydrogen production via water electrolysis rely on batteries to power the reaction, while the hydrogen production reaction of this invention does not require batteries, has a very fast reaction speed, and can generate hydrogen in real time to power the engine.

[0026] In addition to providing energy for common power generation engines, this invention can also serve as a distributed power source / emergency power source to provide electricity for communication base stations, remote areas, or specific facilities, avoiding the complexities of hydrogen storage and transportation. It can also be used to power specific transportation vehicles, such as various motor vehicles, on fixed routes in mines, ports, and other locations. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0028] Figure 2 This is a process flow diagram of the apparatus of the present invention.

[0029] In the diagram: 1. Hydrogen generator; 2. Hydrogen buffer tank; 3. Liquid storage tank; 4. Powder storage tank; 5-1. First electrically controlled check valve; 5-2. Second electrically controlled check valve; 5-3. Third electrically controlled check valve; 5-4. Fourth electrically controlled check valve; 6. Filter; 7. Top cover; 8. Tank cover; 9-1. Primary reaction tank; 9-2. Secondary reaction tank; 9-3. Tertiary reaction tank; 10. Fixing rod; 11-1. First pressure sensor; 11-2. Second pressure sensor; 12-1. First hydrogen sensor; 2-2, Second hydrogen sensor; 13-1, First feed port; 13-2, Second feed port; 14-1, First vent hole; 14-2, Second vent hole; 15, Receiving tank; 16, Gravity check valve; 17, Electrically controllable valve; 18, Air inlet; 19, Atomizing fan; 20, Top cover sealing buckle; 21-1, First temperature sensor; 21-2, Second temperature sensor; 22, Tank cover sealing buckle; 23, Gas supply pipe; 24, Drain pipe; 25, Manual drain valve; 26, Liquid level sensor. Detailed Implementation

[0030] The present invention will be further explained below with reference to the embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] Example 1

[0032] like Figure 1As shown, this invention provides an apparatus for preparing hydrogen gas by hydrolyzing aluminum under alkaline conditions. The apparatus includes a hydrogen generator 1, which is a cubic or cylindrical steel tank capable of withstanding 2 to 10 atmospheres of pressure. It comprises a main body and a top cover 7. The top cover 7 is equipped with a first pressure sensor 11-1, a first hydrogen sensor 12-1, and a first temperature sensor 21-1, all connected to an instrument control system. The top cover 7 is sealed to the main body using a top cover sealing buckle 20. Inside the hydrogen generator 1, from top to bottom, are a primary reaction tank 9-1, a secondary reaction tank 9-2, and a tertiary reaction tank 9-3, all fixed by a fixing rod 10. The upper end of the fixing rod 10 is fixed to the top cover 7, and the lower end vertically penetrates the center of each reaction tank, securing the three reaction tanks inside the hydrogen generator 1. The dimensions of the primary reaction tank 9-1, secondary reaction tank 9-2, and tertiary reaction tank 9-3 increase sequentially. The secondary reaction tank 9-2 and tertiary reaction tank 9-3 have a mesh structure. The hydrogen generator 1 is also equipped with a liquid level sensor 26. Above the hydrogen generator 1 are a liquid storage tank 3 and a powder storage tank 4. The liquid storage tank 3 is connected to the primary reaction tank 9-1 via a pipe equipped with a first electrically controlled check valve 5-1, and the powder storage tank 4 is connected to the primary reaction tank 9-1 via a pipe equipped with a second electrically controlled check valve 5-2. The top of the liquid storage tank 3 has a first feed port 13-1 and a first vent 14-1, and the top of the powder storage tank 4 has a second feed port 13-2 and a second vent 14-2. Both feed ports are equipped with sealing caps, and both vents contain desiccant. The hydrogen generator 1 is connected to a hydrogen buffer tank 2 via a pipe, on which a third electrically controlled check valve 5-3 and a filter 6 are installed (the positions of these two are interchangeable, but it is preferable that the filter 6 is closer to the hydrogen buffer tank 2). The hydrogen buffer tank 2 includes a tank body and a tank cover 8 located on top of the tank body. The tank cover 8 is equipped with a second pressure sensor 11-2, a second hydrogen sensor 12-2, and a second temperature sensor 21-2, all connected to the instrument control system. The tank cover 8 is sealed and fixed to the tank body by a tank cover sealing buckle 22. The hydrogen buffer tank 2 also has a gas supply pipe 23 connected to the engine, on which a fourth electrically controlled one-way valve 5-4 is installed. A drain pipe 24 is located at the bottom of the hydrogen buffer tank 2, on which a manual drain valve 25 is installed. The bottom of the hydrogen generator 1 is connected to the receiving tank 15 via a pipe, on which an electrically controllable valve 17 is installed. The receiving tank 15 has an air inlet 18 on one side, and an air filter is provided at the air inlet 18. The top of the receiving tank 15 away from the air inlet 18 has an air outlet, and a gravity check valve 16 is installed at the air outlet. An atomizing fan 19 is installed inside the receiving tank 15, and the atomizing fan 19 is located directly below the outlet of the pipe connecting the hydrogen generator 1 and the receiving tank 15.

[0033] The hydrogen generator 1 and the hydrogen buffer tank 2 are pre-filled with hydrogen at a specified pressure value before leaving the factory.

[0034] The method for preparing hydrogen using the above-described apparatus includes the following steps (taking a pressure of 2 atmospheres as an example):

[0035] (1) Provided that there is sufficient sodium hydroxide solution in the liquid storage tank 3 and sufficient aluminum composite powder in the powder storage tank 4, the engine is started, and the fourth electronically controlled one-way valve 5-4 is automatically opened, and hydrogen is delivered from the hydrogen buffer tank 2 to the engine. The engine uses hydrogen as fuel to supply energy to the system (H). 2(g) + 1 / 2O 2(g) → H2O (g) When the second pressure sensor 11-2 detects a pressure drop in the hydrogen buffer tank 2, the third electrically controlled check valve 5-3 automatically opens, and hydrogen gas from the hydrogen generator 1 is sequentially transported to the hydrogen tank 2 through the third electrically controlled check valve 5-3 and filter 6 (or sequentially through filter 6 and the third electrically controlled check valve 5-3). When the first pressure sensor 11-1 detects a pressure drop in the hydrogen generator 1, the first electrically controlled check valve 5-1 and the second electrically controlled check valve 5-2 automatically open, and sodium hydroxide solution and aluminum composite powder are added to the primary reaction tank 9-1. The two are mixed and react as follows:

[0036] 2Al + 2NaOH + H2O → 2NaAlO2 + 3H2↑

[0037] When the mixture overflows from the primary reaction tank 9-1, it flows into the secondary reaction tank 9-2 to continue the reaction. Then, it flows through the strainer of the secondary reaction tank 9-2 into the tertiary reaction tank 9-3 to continue the reaction. Finally, it flows through the strainer of the tertiary reaction tank 9-3 to the bottom of the hydrogen generator 1, where the bottom contains the reaction byproducts sodium aluminate and other salt solutions. This process continuously generates hydrogen, which is then transported to the engine via the hydrogen buffer tank 2.

[0038] During the reaction, when the first pressure sensor 11-1 detects that the pressure inside the hydrogen generator 1 exceeds 2 atmospheres, the first electrically controlled check valve 5-1 and the second electrically controlled check valve 5-2 simultaneously close, stopping the feeding. When the first pressure sensor 11-1 detects that the pressure inside the hydrogen generator 1 is higher than 1 atmosphere but lower than 2 atmospheres, the first electrically controlled check valve 5-1 and the second electrically controlled check valve 5-2 automatically open again, feeding hydrogen. When the first temperature sensor 21-1 detects that the temperature inside the hydrogen generator 1 is higher than 70°C, the flow rate of the sodium hydroxide solution is increased by adjusting the first electrically controlled check valve 5-1, or the addition of aluminum composite powder is reduced by closing the second electrically controlled check valve 5-2, or both simultaneously, to increase the liquid ratio inside the hydrogen generator 1 for cooling. When the first hydrogen sensor 12-1 or the second hydrogen sensor 12-2 detects that the purity of hydrogen in the hydrogen generator 1 or the hydrogen buffer tank 2 has not reached the target value, the system issues an alarm and waits for corresponding measures to be taken to ensure that the hydrogen purity meets the requirements (such as periodically opening the manual drain valve 25 to drain the water in the hydrogen buffer tank 2). When the level sensor 26 detects that the liquid level of the mixed solution of sodium aluminate and other salts, a reaction byproduct, at the bottom of the hydrogen generator 1 has reached the maximum limit, the electrically controllable valve 17 automatically opens. The mixed solution enters the receiving tank 15 from the bottom of the hydrogen generator 1 and is atomized into mist by the atomizing fan 19. At the same time, air is filtered by the air filter at the air inlet 18 and introduced into the receiving tank 15. The carbon dioxide in the air reacts with the sodium aluminate in the mist as follows:

[0039] NaAlO2 + CO2+ 2H2O → Al(OH)3↓+ NaHCO3

[0040] The reaction produces aluminum hydroxide precipitate, and the remaining air is discharged through the gravity check valve 16 at the outlet. When the level sensor 26 detects that the liquid level of the mixed solution has dropped to the minimum limit, the electrically controlled valve 17 automatically closes, stopping the discharge. During the reaction, the generated water vapor enters the hydrogen buffer tank 2 along with the hydrogen gas, condenses into water inside the tank, and accumulates at the bottom. After the hydrogen production reaction is completed, the manual drain valve 25 can be opened to discharge the water out of the hydrogen buffer tank 2 through the drain pipe 24. A small amount of water should be left in the tank during discharge to prevent hydrogen leakage.

[0041] The hydrogen generator 1 and the hydrogen buffer tank 2 are pre-filled with hydrogen at a pressure of 2 atmospheres. Desiccant is pre-added to the first vent 14-1 and the second vent 14-2.

[0042] (2) After the engine is shut down, the fourth electronically controlled check valve 5-4 automatically closes, stopping the supply of hydrogen to the engine. When the second pressure sensor 11-2 detects that the pressure inside the hydrogen buffer tank 2 reaches 2 atmospheres, the third electronically controlled check valve 5-3 automatically closes. When the first pressure sensor 11-1 detects that the pressure inside the hydrogen generator 1 is lower than 2 atmospheres but higher than 1 atmosphere, the first electronically controlled check valve 5-1 and the second electronically controlled check valve 5-2 are closed simultaneously, stopping the feeding. When the pressure value displayed by the first pressure sensor 11-1 remains unchanged, it proves that the hydrogen production reaction has ended, and the hydrogen stored in the hydrogen generator 1 and the hydrogen buffer tank 2 can be used for the next engine start.

[0043] The receiving tank 15 is opened periodically to collect aluminum hydroxide precipitate and other salt solutions such as sodium carbonate and sodium bicarbonate, or the receiving tank can be replaced for centralized collection by the manufacturer. Aluminum hydroxide can be further processed into boehmite (Al(OH)3 → AlOOH + H2O), or sent back to the aluminum processing plant for recycled aluminum. Other salt solutions such as sodium carbonate and sodium bicarbonate can be post-processed to become raw materials for preparing aluminum composite powder, achieving recycling.

[0044] The process for preparing hydrogen in steps (1) to (2) is as follows: Figure 2 As shown.

[0045] In this embodiment 1, the sodium hydroxide solution concentration is 1M. The aluminum composite powder used is either aluminum powder-sodium chloride composite powder (the mass ratio of aluminum powder to sodium chloride is 1:1) or aluminum powder-sodium chloride-sodium carbonate composite powder (the mass ratio of aluminum powder to sodium chloride and sodium carbonate is 1:0.5:0.5). When the sodium hydroxide solution or aluminum composite powder is insufficient, open the top of the first feeding port 13-1 and the second feeding port 13-2 to add the powder, and then tighten the feeding caps after adding the powder.

[0046] Example 2

[0047] The difference between this embodiment and Embodiment 1 is that the powder added to the powder storage tank 4 is either an aluminum powder-sodium chloride-tin composite powder (the mass ratio of aluminum powder to sodium chloride and tin is 1:1:0.05) or an aluminum powder-sodium chloride-tin-sodium carbonate composite powder (the mass ratio of aluminum powder to sodium chloride, tin, and sodium carbonate is 1:0.5:0.05:0.5). Compared to Embodiment 1, this embodiment introduces tin into the aluminum composite powder, which acts as a catalyst to increase the reaction rate of hydrogen production. After the hydrogen production reaction is completed, the tin is recovered except for the collection of aluminum hydroxide precipitate and other salt solutions.

[0048] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. An apparatus for preparing hydrogen gas by hydrolyzing aluminum under alkaline conditions, characterized in that, The device includes a hydrogen generator (1), which has a staged reaction tank inside; a liquid storage tank (3) and a powder storage tank (4) are provided above the hydrogen generator (1), and the liquid storage tank (3) and the powder storage tank (4) are respectively connected to the reaction tank through pipes with one-way valves; the top of the hydrogen generator (1) is connected to a hydrogen buffer tank (2) through a pipe with one-way valves, and the hydrogen buffer tank (2) is provided with a gas supply pipe (23) with an electrically controlled one-way valve connected to the engine; the bottom of the hydrogen generator (1) is connected to a receiving tank (15) through a pipe with an electrically controlled valve (17).

2. The apparatus according to claim 1, characterized in that, The staged reaction pool includes a primary reaction pool (9-1), a secondary reaction pool (9-2), and a tertiary reaction pool (9-3) arranged sequentially from top to bottom. The three are fixed inside the hydrogen generator (1) by a fixing rod (10) that passes through the center of each reaction pool. The size of the primary reaction pool (9-1), the secondary reaction pool (9-2), and the tertiary reaction pool (9-3) increases sequentially. The secondary reaction pool (9-2) and the tertiary reaction pool (9-3) are mesh structures.

3. The apparatus according to claim 1, characterized in that, The top of the liquid storage tank (3) is provided with a first vent hole (14-1) and a first feeding port (13-1) with a sealing cap; the top of the powder storage tank (4) is provided with a second vent hole (14-2) and a second feeding port (13-2) with a sealing cap, and both the first vent hole (14-1) and the second vent hole (14-2) are filled with desiccant.

4. The apparatus according to claim 1, characterized in that, A filter (6) is also installed on the pipe connecting the hydrogen generator (1) and the hydrogen buffer tank (2).

5. The apparatus according to claim 1, characterized in that, The receiving tank (15) has an air inlet (18) on one side, an air filter is provided at the air inlet (18), and an air outlet is provided at the top of the receiving tank (15) away from the air inlet (18). A gravity check valve (16) is installed at the air outlet. An atomizing fan (19) is installed inside the receiving tank (15), and the atomizing fan (19) is located directly below the outlet of the pipe connecting the hydrogen generator (1) and the receiving tank (15).

6. The apparatus according to claim 1, characterized in that, The hydrogen generator (1) is also equipped with a liquid level sensor (26); the bottom of the hydrogen buffer tank (2) is equipped with a drain pipe (24), and a manual drain valve (25) is installed on the drain pipe (24).

7. A method for preparing hydrogen using the apparatus as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) When the engine is started, the fourth electronically controlled check valve (5-4) automatically opens, and hydrogen is delivered from the hydrogen buffer tank (2) to the engine; as the pressure in the hydrogen buffer tank (2) decreases, the third electronically controlled check valve (5-3) automatically opens, and hydrogen is delivered from the hydrogen generator (1) to the hydrogen buffer tank (2); as the pressure in the hydrogen generator (1) decreases, the first electronically controlled check valve (5-1) and the second electronically controlled check valve (5-2) automatically open, and sodium hydroxide solution and aluminum composite powder are simultaneously added to the primary reaction tank (9-1) for mixing and reaction. Subsequently, the mixture overflows from the primary reaction tank (9-1) to the secondary reaction tank (9-2), and then passes through the secondary reaction tank (9-2) and the third reaction tank in sequence. The leak in the stage reaction tank (9-3) reaches the bottom of the hydrogen generator (1), and hydrogen is continuously generated in this process. When the liquid level sensor (26) detects that the liquid level of the mixed solution at the bottom of the hydrogen generator (1) reaches the maximum limit, the electrically controlled valve (17) automatically opens. The mixed solution enters the receiving tank (15) from the bottom of the hydrogen generator (1) and is atomized into mist by the atomizing fan (19). Sodium aluminate reacts with carbon dioxide in the air introduced from the air inlet (18) to generate aluminum hydroxide. The remaining air is discharged from the gravity check valve (16) at the air outlet. When the liquid level sensor (26) detects that the liquid level of the mixed solution drops to the minimum limit, the electrically controlled valve (17) automatically closes. (2) After the engine is shut down, the fourth electronically controlled check valve (5-4) automatically closes; then, when the pressure inside the hydrogen buffer tank (2) reaches the limit pressure, the third electronically controlled check valve (5-3) automatically closes; finally, when the pressure inside the hydrogen generator (1) is lower than the limit pressure but greater than 1 atmosphere, the first electronically controlled check valve (5-1) and the second electronically controlled check valve (5-2) close simultaneously. The aluminum hydroxide and other products in the receiving tank (15) are collected periodically. The hydrogen generator (1) and hydrogen buffer tank (2) are pre-filled with hydrogen at a specified pressure before hydrogen production, and sufficient sodium hydroxide solution and aluminum composite powder are added to the liquid storage tank (3) and powder storage tank (4), respectively.

8. The method according to claim 7, characterized in that, The concentration of the sodium hydroxide solution is 0.5–5.0 M, and the aluminum composite powder comprises aluminum powder and sodium chloride, with a mass ratio of aluminum powder to sodium chloride of 1–6:

1.

9. The method according to claim 8, characterized in that, The aluminum composite powder also includes one or two of a metal or sodium carbonate, wherein the metal is selected from one or more of magnesium, nickel, iron, calcium, iridium or tin.

10. The method according to claim 9, characterized in that, When the aluminum composite powder contains metal, the mass ratio of aluminum powder to metal is 1:0.01 to 0.1; when the aluminum composite powder contains sodium carbonate, the mass ratio of aluminum powder to sodium carbonate is 1:0.5 to 1.

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