Intelligent control and optimization system for hydrogen production from aluminum hydrolysis

Abstract

The present invention discloses an intelligent control and optimization system in the production of hydrogen by hydrolysis of aluminum, and relates to the field of automatic control technology. The system comprises: a reaction kinetics analysis unit, a fluid field optimization unit and an adaptive intelligent control unit; the reaction kinetics analysis unit is used to obtain the aluminum powder reaction rate according to the aluminum powder activity characterization parameter of the aluminum powder; the hydrogen prediction rate is obtained according to the aluminum powder reaction rate, and the bubble growth equation is constructed to obtain the bubble growth rate; the fluid field optimization unit is used to analyze the mass transfer and heat transfer coupling effect of the reaction process, analyze the influence of stirring on fluid motion, obtain the flow field velocity distribution, and predict the reaction progress; the adaptive intelligent control unit is used to dynamically adjust the stirring rate according to the reaction progress, reaction pressure, hydrogen prediction rate, flow field velocity distribution and aluminum powder activity characterization parameters. The present invention improves the utilization rate of aluminum powder and the hydrogen production rate.

Description

Technical Field

[0001] The invention relates to the field of automatic control technology, and in particular to an intelligent control and optimization system in the production of hydrogen by hydrolyzing aluminum. Background Art

[0002] As a clean and efficient energy carrier, hydrogen energy plays a vital role in the transformation of the global energy structure. There are many methods for preparing hydrogen, including natural gas reforming, water electrolysis, biomass hydrogen production, and metal hydrolysis hydrogen production. Among them, metal hydrolysis hydrogen production has broad application prospects in portable hydrogen energy supply, fuel cell applications, and emergency energy systems because of its advantages such as no need for additional power input, high energy density, and strong portability. Aluminum, as a metal with abundant reserves in the earth's crust, has a high theoretical hydrogen production capacity.

[0003] At present, researchers have proposed a variety of optimization methods to address the problem of limited reaction rate in aluminum hydrolysis to produce hydrogen, including strategies such as metal alloying, chemical activation treatment, and catalyst introduction. Metal alloying is an important strategy to improve the hydrolysis activity of aluminum powder. Low-melting-point metals such as gallium (Ga), indium (In), and tin (Sn) are usually used as alloying elements to destroy the continuity of the oxide film and reduce the activation energy of aluminum powder. For example, some studies have shown that Al-Ga-In-Sn low-melting-point alloys can be rapidly hydrolyzed to produce hydrogen at room temperature and pressure without forming a dense passivation film. However, the alloying process has a high cost, and the uneven distribution of alloying elements may lead to the instability of the hydrolysis reaction and affect the efficiency of hydrogen production. In addition, the alloy may undergo phase separation during storage, resulting in degradation of the hydrolysis performance, limiting its practicality. The chemical activation treatment method removes the oxide film on the aluminum surface by acid washing, alkali treatment, or fluoride modification, so that the aluminum powder surface is in a highly active state. For example, treating aluminum powder with a strong alkali (NaOH) solution can effectively increase its hydrolysis reaction rate, but this method requires the addition of an alkaline medium, which increases corrosiveness and may cause impurities in hydrogen, affecting the subsequent application of fuel cells. In addition, the rate of aluminum hydrolysis reaction under alkaline conditions is often difficult to control, and it is easy to react violently or terminate prematurely, which limits its promotion in engineering applications. Studies have found that some transition metals (such as nickel, cobalt, iron, etc.) and their oxides can promote the hydrolysis reaction of aluminum and increase the hydrogen production rate. For example, Ni(OH)2 and Co(OH)2 can be used as catalysts to react electrochemically with the surface of aluminum powder, promote the dissolution of aluminum and accelerate the release of hydrogen. However, the amount of catalyst added, the uniformity of dispersion and the long-term stability are important factors affecting the reaction effect. Some catalysts may gradually passivate during the hydrolysis process, resulting in a decrease in the reaction rate. In addition, the introduction of catalysts may increase system costs and reduce overall economic efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide an intelligent control and optimization system in the production of hydrogen by hydrolyzing aluminum, so as to improve the utilization rate of aluminum powder and the hydrogen production rate.

[0005] In order to solve the above technical problems, the present invention provides an intelligent control and optimization system for the production of hydrogen by hydrolysis of aluminum, the system comprising: a reaction kinetics analysis unit, a fluid field optimization unit and an adaptive intelligent control unit;

[0006] The reaction kinetics analysis unit is used to construct an aluminum powder reaction rate equation taking into account the surface activity of the aluminum powder according to the aluminum powder activity characterization parameter of the aluminum powder, and obtain the aluminum powder reaction rate; according to the aluminum powder reaction rate, using Gibbs free energy and gas escape coefficient, establish a hydrogen production rate prediction equation to obtain the hydrogen prediction rate; according to the hydrogen prediction rate, construct a bubble growth equation to obtain the bubble growth rate;

[0007] The fluid field optimization unit is used to analyze the mass transfer and heat transfer coupling effect of the reaction process, establish a mass transfer and heat transfer model, calculate the temperature field under the combined action of reaction heat release and bubble dynamics, and analyze the influence of stirring on fluid movement. By using the fluid permeability and thermal expansion effect, a flow field distribution model is constructed according to the temperature field to obtain the flow field velocity distribution. The flow field velocity distribution is combined with bubble dynamics to predict the reaction progress.

[0008] The adaptive intelligent control unit is used to dynamically adjust the stirring rate according to the reaction progress, reaction pressure, hydrogen predicted rate, flow field velocity distribution and aluminum powder activity characterization parameters, specifically including: when the reaction progress exceeds a set threshold, reducing the stirring rate; when the reaction pressure increases, resulting in an increased risk of bubble breakage, reducing the stirring rate; when the surface activity of the aluminum powder decreases, increasing the stirring rate.

[0009] Furthermore, the parameters characterizing the activity of aluminum powder include: aluminum powder specific surface area, aluminum powder concentration, aluminum powder surface energy, aluminum powder critical nucleus radius and aluminum powder particle size.

[0010] Furthermore, the aluminum powder reaction rate equation is expressed using the following formula:

[0011] ;

[0012] in, Represents the surface activity function of aluminum powder, represents the surface activity of aluminum powder, the formula is: ; For the Arrhenius term; is the reaction activation energy; is the gas constant; is the temperature field, representing the time The temperature at , in Kelvin; is the specific surface area of ​​aluminum powder, that is, the surface area of ​​aluminum powder per unit mass. The larger the value, the more reaction interfaces there are and the higher the reaction rate of aluminum powder. is the aluminum powder concentration; is the concentration of water; The surface energy of aluminum powder represents the energy of the aluminum-water interface and affects the difficulty of aluminum dissolution. The higher the surface energy, the easier it is for aluminum powder to react. is the Boltzmann constant; For time The critical nucleus radius of aluminum powder at , reflects the thickness of the aluminum oxide film and determines the activity of aluminum: Increase, indicating that the oxide film of aluminum powder is thicker. will decrease, indicating that the reactivity of aluminum powder decreases; if Decrease means that the oxide film of aluminum powder is damaged or activated. , which means that the hydrolysis reaction of aluminum powder is more likely to occur; is the reaction rate constant, dimensionless, and is a set value, representing the maximum aluminum powder reaction rate without an energy barrier; For time.

[0013] Furthermore, the hydrogen production rate prediction equation is expressed using the following formula:

[0014] ;

[0015] in, is the gas escape coefficient; is the reaction rate of aluminum powder; is the stoichiometric coefficient, derived from the aluminum hydrolysis reaction: , where 2 mol of aluminum will produce 3 mol of hydrogen, so the hydrogen production rate is the aluminum consumption rate times; is the molar mass of hydrogen; is standard atmospheric pressure; is the Gibbs free energy change, if , indicating that the reaction proceeds spontaneously, is approximately 0, then , that is, the reaction completely releases hydrogen; if , indicating that the reaction is not spontaneous, If it is close to 1, the term approaches 0, which means that almost no hydrogen is released; For time Response pressure at the time; For time The predicted hydrogen rate at .

[0016] Furthermore, the bubble growth equation is expressed using the following formula:

[0017] ;

[0018] in, It is the total pressure composed of hydrostatic pressure and surface tension pressure; is the bubble radius; is the liquid density; is the surface tension of the reaction solution; is the gravitational acceleration constant; is the liquid level height.

[0019] Furthermore, the mass transfer and heat transfer model is expressed using the following formula:

[0020] ;

[0021] in, is the number of bubbles per unit volume; is the thermal diffusion coefficient, ; is the reaction enthalpy; is the volume of a single bubble; is the temperature field; is the dynamic viscosity of the reaction liquid; is the specific heat capacity of the reaction solution; is the thermal conductivity of the reaction liquid; is the volume of the reaction vessel.

[0022] Furthermore, the flow field distribution model is expressed using the following formula:

[0023] ;

[0024] in, is the reaction pressure gradient; is the thermal expansion coefficient of the reaction liquid; is the vertical unit vector, pointing in the direction of gravity; is the specific volume, which indicates the volume occupied by the unit mass of the reaction liquid. The larger it is, the smaller the density of the reaction liquid is. is the unit vector of the bubble movement direction, which is approximated as the upward floating direction in the case of low stirring or natural convection, and is the opposite direction of gravity. ; is the velocity distribution of the flow field.

[0025] Furthermore, the reaction progress is predicted by combining the flow field velocity distribution and bubble dynamics through the following formula:

[0026] ;

[0027] in, is the surface area of ​​a single bubble; is the particle size of aluminum powder; is the effective diffusion coefficient, and its value range is arrive ; is the cross-sectional area of ​​the reaction vessel; is the time-integrated variable; Represents vector modulus operation; For time The predicted reaction progress.

[0028] Furthermore, the stirring rate is dynamically adjusted by the following formula:

[0029] ;

[0030] in; is the set reference speed; is the maximum hydrogen production rate; is the surface activity of the set standard aluminum powder; The calculated time The stirring rate at this time is controlled according to this value.

[0031] The intelligent control and optimization system for producing hydrogen by hydrolyzing aluminum of the present invention has the following beneficial effects:

[0032] The present invention makes the prediction of the hydrolysis reaction rate of aluminum powder more accurate by constructing a reaction kinetic model. Traditional aluminum hydrolysis reaction rate models are usually based on empirical formulas, which fail to fully consider the dynamic changes of factors such as aluminum powder surface activity, oxide film thickness and temperature. Therefore, there are large fluctuations in reaction rate between different aluminum powder batches, which makes it difficult for the hydrogen production system to remain stable. The present invention introduces a surface activity correction function so that the model can evaluate the activity state of aluminum powder in real time, and combines the thermodynamic properties of the hydrolysis reaction to establish a more accurate reaction rate calculation method. In this way, no matter how the oxidation degree of the aluminum powder is, the system can automatically adjust the reaction rate prediction value according to its surface characteristics to ensure the stability of the hydrogen production process.

[0033] In addition, the kinetic model can also be combined with external environmental parameters, such as temperature, pressure and liquid flow state, so that the hydrogen production process can adapt to different operating conditions and improve the environmental adaptability of the system. The present invention fully considers the influence of bubble dynamics in the hydrogen release process to ensure the stability of hydrogen escape. In the hydrolysis of aluminum reaction, hydrogen is generated in the form of bubbles, and the growth, merging and escape process of bubbles have an important influence on the hydrogen production rate. If the bubbles are retained in the liquid phase, it may cause the local hydrogen concentration to increase, reduce the reaction rate, and may affect the subsequent collection and utilization of hydrogen. If the bubbles burst prematurely, it may cause the incompletely grown hydrogen to escape, reducing the hydrogen production efficiency. To this end, the present invention proposes an optimization method based on bubble growth dynamics, by calculating the volume change rate of the bubble, the pressure equilibrium state and the fluid shear force influence, accurately predicting the escape behavior of the bubble, and combining the intelligent control system to optimize the stirring strategy, so that the hydrogen release process is more stable and controllable. This optimization strategy not only improves the release rate of hydrogen, but also reduces the residence time of the bubble in the liquid phase, thereby improving the overall efficiency of hydrogen production.

[0034] The present invention solves the problems of uneven distribution of aluminum powder, formation of local stagnant areas and low mass transfer efficiency in traditional hydrogen production systems. Since the aluminum hydrolysis reaction involves solid, liquid and gas three-phase flow, the circulation mode of the fluid directly affects the suspension state of the aluminum powder and the diffusion efficiency of water molecules. The traditional mechanical stirring method usually adopts a fixed speed or a simple staged adjustment strategy, and fails to optimize it in combination with the fluid dynamics characteristics. Therefore, in the high hydrogen production stage, the flow field may be disturbed by the aggregation of bubbles, which reduces the actual efficiency of stirring. The present invention optimizes the circulation mode of the fluid by constructing a flow field distribution model, combining the pressure gradient, thermal buoyancy effect and bubble motion trajectory, so that the driving effect of stirring on the fluid is maximized, the mixing efficiency of aluminum powder is improved, and the full contact between aluminum powder and water is ensured. In addition, the fluid optimization method can also dynamically adjust the flow mode at different reaction stages, such as enhancing convection in the early stage of the reaction to improve the suspension of aluminum powder, and optimizing the stirring structure in the later stage of the reaction to make hydrogen escape smoother and avoid excessive interference of bubbles on the flow field, thereby improving the overall hydrogen production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the system structure of an intelligent control and optimization system for hydrogen production by aluminum hydrolysis provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1, reference Figure 1 : An intelligent control and optimization system in the production of hydrogen by hydrolysis of aluminum, the system comprising: a reaction kinetics analysis unit, a fluid field optimization unit and an adaptive intelligent control unit.

[0039] The reaction kinetics analysis unit is used to construct an aluminum powder reaction rate equation taking into account the surface activity of the aluminum powder according to the aluminum powder activity characterization parameters of the aluminum powder to obtain the aluminum powder reaction rate; according to the aluminum powder reaction rate, using Gibbs free energy and gas escape coefficient, a hydrogen production rate prediction equation is established to obtain the hydrogen prediction rate; according to the hydrogen prediction rate, a bubble growth equation is constructed to obtain the bubble growth rate.

[0040] The fluid field optimization unit is used to analyze the mass transfer and heat transfer coupling effect of the reaction process, establish a mass transfer and heat transfer model, calculate the temperature field under the combined action of reaction heat release and bubble dynamics, and at the same time, analyze the influence of stirring on fluid movement, use the fluid permeability and thermal expansion effect, build a flow field distribution model according to the temperature field, obtain the flow field velocity distribution, and combine the flow field velocity distribution with bubble dynamics to predict the reaction progress.

[0041] The adaptive intelligent control unit is used to dynamically adjust the stirring rate according to the reaction progress, reaction pressure, hydrogen predicted rate, flow field velocity distribution and aluminum powder activity characterization parameters, specifically including: when the reaction progress exceeds a set threshold, reducing the stirring rate; when the reaction pressure increases, resulting in an increased risk of bubble breakage, reducing the stirring rate; when the surface activity of the aluminum powder decreases, increasing the stirring rate.

[0042] Specifically, since the reaction characteristics of aluminum powder are affected by factors such as surface activity, oxide film thickness, temperature, and particle size, this system first constructs the reaction rate equation of aluminum powder by characterizing the activity of aluminum powder, so that the reaction rate can be adaptively adjusted with changes in environmental conditions. The reaction rate depends not only on the reaction temperature, but also on the specific surface area of ​​aluminum powder, water concentration, and surface activity coefficient, where the surface activity function is used to describe the inhibitory effect of the degree of oxidation on the reaction rate of the aluminum powder surface. The presence of an oxide film usually reduces the reactivity of aluminum powder, but as the reaction proceeds, the growth of bubbles, the effect of stirring, and the shear force of the fluid may affect the rupture of the oxide film, thereby dynamically changing the effective reaction area of ​​the aluminum powder. Therefore, the system establishes an effective activity model of aluminum powder through thermodynamic analysis combined with the calculation of Gibbs free energy, so that the reaction rate equation can accurately predict the aluminum consumption rate under different temperatures and different oxide film thicknesses. After obtaining the reaction rate of aluminum powder, the unit further uses this information to derive the hydrogen production rate. Since the aluminum hydrolysis process is an exothermic reaction and is affected by the gas evolution dynamics, the release of hydrogen depends not only on the aluminum consumption rate, but also on the bubble dynamics of the system. To this end, the system uses Gibbs free energy and gas evolution coefficient to establish a prediction model for hydrogen yield, where Gibbs free energy determines the spontaneity of the reaction, and the gas evolution coefficient reflects the ease with which hydrogen is transferred from the liquid phase to the gas phase. The release rate of hydrogen is affected by factors such as system temperature, pressure, fluid flow state, and bubble size distribution. Especially under high reaction rate conditions, the aggregation effect of bubbles may cause local reaction stagnation or reduce the mass transfer rate. Therefore, the model of this unit not only considers the contribution of aluminum consumption rate to hydrogen generation, but also introduces a gas evolution correction factor to compensate for the non-ideal effects caused by bubble dynamics.

[0043] With the generation of hydrogen, the growth of bubbles becomes an important factor affecting the reaction stability of the system. Therefore, this unit further constructs a bubble growth dynamics model to describe the evolution of bubble size over time and its impact on the overall flow field. In the aluminum hydrolysis reaction system, the generation and growth of bubbles is a dynamic process, which is affected by the coupling of factors such as reaction rate, surface tension, liquid density, and hydrostatic pressure. If the bubble grows too fast, its aggregation effect may hinder the contact between water and aluminum powder and reduce the reaction efficiency; if the bubble grows unevenly, it may cause flow blockage in the local reactor and affect the mixing effect of the fluid. Therefore, the system constructs a bubble growth equation, analyzes the volume change rate of the bubble, and combines the pressure field and flow velocity distribution in the liquid phase to predict the dynamic behavior of the bubble. In particular, the system also considers the combined effect of hydrostatic pressure and surface tension, analyzes the growth mode of bubbles under different fluid conditions, and provides data support for adaptive stirring control. By combining the aluminum dissolution kinetics, hydrogen release rate and bubble growth model, the unit can provide a complete dynamic description of the aluminum hydrolysis reaction and provide key predictive data for real-time control of the system, so that subsequent flow field optimization and stirring adjustment can be adaptively adjusted based on scientific calculations.

[0044] In the process of hydrolyzing aluminum to produce hydrogen, heat transfer is crucial to the reaction rate. The dissolution reaction of aluminum powder is an exothermic process. Local high-temperature areas will accelerate the oxidation reaction of aluminum, but at the same time may lead to the accelerated formation of an oxide film on the surface of the aluminum powder, reducing the reaction rate. Since the reaction heat is mainly diffused in the liquid phase by convection and conduction, and the heat diffusion rate of the liquid is much smaller than the convection driving effect of the bubbles, the fluid motion plays a leading role in the homogenization of the temperature field. If the temperature gradient is too large, the local high temperature area may cause a large number of bubbles to accumulate, making it difficult for hydrogen to escape smoothly. At the same time, high temperature may induce aluminum powder agglomeration, reduce the specific surface area, and ultimately lead to reaction inhomogeneity. Therefore, the fluid field optimization unit first constructs a temperature field distribution model based on the heat transfer equation to calculate the temperature changes at different positions in the liquid phase, and combines the fluid dynamics model to analyze the influence of the convection effect on the temperature uniformity. On this basis, the unit further considers the role of flow field optimization on the bubble detachment behavior, and optimizes the formation, growth and release process of bubbles by adjusting the fluid motion mode, so that hydrogen can escape from the liquid phase more smoothly. Inside the reactor, the organization of fluid flow directly determines the mixing efficiency of aluminum powder and water and affects the hydrogen production rate. Since the particle size of aluminum powder is much smaller than that of liquid phase fluid, the movement of aluminum powder in the fluid is affected by multiple forces such as gravity, buoyancy, fluid shear force and Brownian motion. How to optimize the fluid flow field so that the aluminum powder is always in a good suspension state is the key to improving the reaction rate. On this basis, the fluid field optimization unit establishes a flow field distribution model and calculates the spatial distribution of the fluid velocity field to ensure that the stirring energy can be effectively transferred to the entire reaction system without shear damage caused by excessive local flow rate or aluminum powder sedimentation caused by too low flow rate. At the same time, the system combines the fluid permeability and thermal expansion effect to form a dynamic balance between the temperature field and the flow field, avoiding excessive bubbling caused by local heat accumulation. Especially when the aluminum powder particles are fine, excessive flow may cause aluminum powder to aggregate in the fluid, thereby forming a reaction dead zone and affecting the overall reaction efficiency. Therefore, the system can adaptively adjust the stirring mode based on the temperature distribution and flow field characteristics, so that the aluminum powder can be evenly distributed in the reaction liquid and ensure the stability of the reaction rate. In addition, bubble dynamics plays a crucial role in the process of producing hydrogen by hydrolysis of aluminum. The rate of hydrogen production is affected by the rate of aluminum powder consumption, while the growth, merging and escape behavior of bubbles determine the efficiency of hydrogen release from the liquid phase to the gas phase. If the bubbles aggregate excessively, bubble clusters may form, hindering the contact between aluminum powder and water, and even causing stirring failure, reducing the reaction efficiency.

[0045] On the other hand, the rapid detachment of bubbles can not only increase the release rate of hydrogen, but also reduce gas retention in the liquid phase and improve mass transfer efficiency. Therefore, the fluid field optimization unit constructs a model based on bubble growth dynamics to describe the entire process of bubble growth, expansion, merging and final escape from nucleation. The system calculates the growth rate of bubbles and predicts the average residence time of bubbles in combination with the velocity distribution of the flow field, thereby optimizing the stirring strategy to prevent bubble retention. In addition, the unit also uses the calculation results of hydrostatic pressure and surface tension to optimize the growth pattern of bubbles under different liquid depths, and combines the influence of fluid shear force to ensure that the formation and release of bubbles are in the optimal state, which can ensure the rapid escape of hydrogen without affecting the stability of aluminum powder due to excessive bubble disturbance.

[0046] In the process of aluminum hydrolysis, the stirring rate directly affects the reaction kinetics, mass transfer efficiency and the behavior of bubbles. If the stirring rate is too high, the bubbles may break, which will hinder the hydrogen escape path. At the same time, the turbulence intensity of the liquid will increase, which will increase the probability of collision between aluminum powder particles, thereby promoting particle agglomeration and reducing the reaction surface area. On the other hand, if the stirring rate is too low, aluminum powder may settle, making it unable to fully contact with water, thereby reducing the reaction rate. Therefore, the adaptive intelligent control unit of the system first collects key state parameters in real time, including reaction progress, reaction pressure, hydrogen release rate, flow field velocity distribution and aluminum powder activity. Through the data fusion algorithm, these multi-source information are analyzed to construct a multivariable control decision model to determine whether the current system is in the optimal operating state. In order to ensure the stability of the reaction process, the unit sets a dynamic adjustment strategy for different working conditions. When the reaction progress exceeds the set threshold, the system will reduce the stirring rate to reduce interference with bubbles and reduce mechanical energy consumption. In the early stage of the reaction, the aluminum powder has less contact with water, and the stirring rate usually needs to be maintained at a high level to ensure the uniform distribution of the aluminum powder. However, as the reaction proceeds, the aluminum powder is gradually consumed, and the solid content in the system decreases. Excessive stirring not only does not help improve the efficiency of hydrogen production, but may also cause excessive turbulence intensity, making it impossible for bubbles to merge and escape smoothly. Therefore, when the system detects that the reaction progress is close to completion, the adaptive intelligent control unit will gradually reduce the stirring rate according to the downward trend of the hydrogen release rate, so that the reaction process enters an efficient final stage, ensuring that the aluminum powder is fully utilized while reducing unnecessary stirring power consumption.

[0047] The change of reaction pressure is also an important basis for the regulation of stirring rate. In the process of hydrolysis of aluminum to produce hydrogen, the continuous generation of hydrogen will cause the local pressure in the system to rise. Especially under the condition of high hydrogen production rate, the accumulation of bubbles may cause the phenomenon of local pressure increase. The adaptive intelligent control unit determines whether there is a risk of excessive bubble accumulation by monitoring the change of system pressure. If the system detects that the pressure rises too fast, it means that the bubbles have not been able to leave the liquid phase in time. At this time, appropriately reducing the stirring rate can reduce the breakage of bubbles, so that larger bubbles can float up smoothly and escape from the reaction system, thereby maintaining a stable hydrogen production environment. In addition, the increase in pressure may also be related to local blockage of the flow field. For example, when the circulation of the liquid is blocked, bubbles may be retained in local areas, resulting in the inability to release the gas phase in time. At this time, the system can combine the information of the flow field velocity distribution to comprehensively judge whether the stirring mode needs to be adjusted, such as changing the rotation direction of the stirring blade or intermittently adjusting the stirring intensity to optimize the bubble escape path and maintain the patency of the system. The change of the surface activity of aluminum powder is one of the important factors affecting the reaction efficiency. As the reaction proceeds, the surface state of the aluminum powder will continue to evolve. In the initial stage, the surface activity of the aluminum powder is relatively high, but as the oxide film forms, the reaction rate may gradually decrease. The thickness of the oxide film determines whether water molecules can diffuse smoothly to the active sites of aluminum, and the rupture of the oxide film depends on the external fluid shear force and changes in the chemical environment. The adaptive intelligent control unit calculates the surface activity parameters of the aluminum powder in real time. When the surface activity of the aluminum powder is detected to decrease, the system will increase the stirring rate to increase the fluid shear force, promote the rupture of the oxide film, expose the new aluminum surface, and restore the reaction activity. In addition, the thickness of the oxide film may vary in different regions, so the system can combine the flow field distribution information to identify the spatial distribution state of the aluminum powder in the reactor, and specifically enhance the stirring intensity of the local area, so that all aluminum powder particles can participate in the reaction evenly, avoiding the reaction stagnation caused by the thickening of the local oxide film. Compared with the traditional fixed stirring mode, the adaptive intelligent control unit of the invention introduces a multivariable control strategy to enable the stirring rate to be dynamically adjusted with the change of the system state, thereby effectively improving the stability of the reaction and the hydrogen production. Traditional aluminum hydrolysis reaction stirring systems usually use a fixed speed and cannot adapt to different working conditions in real time. Therefore, bubble breakage problems are prone to occur in the high reaction rate stage, while aluminum powder sedimentation problems are prone to occur in the low reaction rate stage.

[0048] Example 2: The parameters characterizing the activity of aluminum powder include: aluminum powder specific surface area, aluminum powder concentration, aluminum powder surface energy, aluminum powder critical nucleus radius and aluminum powder particle size.

[0049] Specifically, among these characterization parameters, the specific surface area of ​​aluminum powder is a key factor in measuring the activity of aluminum powder. The larger the specific surface area, the more reaction interfaces per unit mass of aluminum powder, making it easier for water molecules to contact with aluminum powder, thereby increasing the reaction rate. The specific surface area is mainly affected by the particle size of aluminum powder and the surface roughness of the particles. Nano- or micron-sized aluminum powders usually have higher specific surface areas. Therefore, under the same mass conditions, smaller particles of aluminum powder usually react faster than large particles. However, the larger the specific surface area, the better. Too small aluminum powder is easy to aggregate together due to van der Waals forces to form secondary particle agglomerations, thereby reducing the actual reactive surface area. Therefore, the system combines the particle size and distribution characteristics of aluminum powder, optimizes the calculation method of specific surface area, and adds a particle dispersion strategy to the stirring control to ensure that the aluminum powder always maintains a suitable distribution state in the reaction liquid. Aluminum powder concentration is another key factor affecting reaction activity. In the kinetic equation of aluminum hydrolysis reaction, the aluminum powder concentration directly affects the hydrogen release rate. A higher concentration of aluminum powder can provide more reactants, but if the concentration is too high, it may cause aluminum powder to accumulate in local areas, forming a sediment layer, which limits the contact between aluminum powder and water. In addition, too high aluminum powder concentration may also lead to excessive generation of bubbles, aggravating the aggregation of bubbles in the system and affecting the release of hydrogen. Therefore, when calculating the reaction rate, the system will dynamically monitor the aluminum powder concentration, and adjust the stirring strategy in combination with the feedback information of the fluid field optimization unit to maintain a uniform distribution of aluminum powder concentration and ensure that the reaction can proceed efficiently.

[0050] The surface energy of aluminum powder is one of the key chemical properties that determine the activity of aluminum powder. It describes the surface free energy state of aluminum powder in the liquid phase and is closely related to the thickness of the oxide film and the surface roughness of the aluminum powder. In the hydrolysis of aluminum, the surface energy of aluminum powder affects the adsorption and diffusion behavior of water molecules on the aluminum surface, thereby affecting the reaction rate. Aluminum powder with high surface energy usually has higher reactivity because its atomic arrangement is less stable and it is easy to react with water. However, a dense oxide film often forms on the surface of aluminum powder exposed to air for a long time, which reduces the surface energy of aluminum powder and makes it difficult to react with water. Therefore, this system introduces surface energy parameters and combines the characteristics of aluminum powder oxide layer thickness, particle roughness, etc. to construct a surface activity correction model to calculate the effective reaction energy of aluminum powder under different states, and optimize the stirring strategy in the adaptive intelligent control unit to enhance the liquid phase shear force, promote the rupture of the oxide film, and keep the surface energy of aluminum powder at a level suitable for the reaction. The critical nucleus radius of aluminum powder is an important parameter to measure the newly generated microstructure of aluminum powder during the reaction process. It determines the nucleus growth rate and surface structure evolution of aluminum powder. During the hydrolysis of aluminum, the surface of aluminum powder may undergo structural rearrangement to form new nuclei, thus affecting the reaction activity. A smaller critical nucleus radius means that it is easier for new growth points to form on the surface of aluminum powder, thereby accelerating the reaction. However, if the nucleus size is too small, it may lead to stress accumulation during the reaction and affect the stability of aluminum powder. Therefore, when calculating the activity of aluminum powder, the system takes into account the influence of the critical nucleus radius, and optimizes the microstructure control strategy of aluminum powder in combination with the reaction temperature, pressure and stirring intensity to ensure that the aluminum powder always maintains a high reactivity during the reaction. The particle size of aluminum powder is one of the most basic parameters affecting the reaction rate of aluminum powder, which determines the specific surface area and reaction kinetic characteristics of aluminum powder. Aluminum powder with a smaller particle size usually has a faster reaction rate than aluminum powder with a larger particle size because it has a larger specific surface area and can provide more reaction sites. However, aluminum powder that is too small is prone to agglomeration in the liquid phase, thereby reducing the reaction activity. Therefore, when calculating the influence of aluminum powder particle size on the reaction, the system combines the particle agglomeration model and optimizes the stirring strategy in the fluid field optimization unit to prevent excessive aggregation of particles. In addition, the particle size distribution of aluminum powder is also crucial to the stability of the reaction. If the particle size distribution of aluminum powder is too wide, it may lead to uneven reaction rates of aluminum powders of different particle sizes, affecting the overall reaction efficiency. Therefore, when calculating the activity of aluminum powder, the system uses a particle distribution correction method to optimize the particle size distribution of aluminum powder, so that aluminum powders of different sizes can react synergistically and improve the overall hydrogen production efficiency.

[0051] Example 3: The reaction rate equation of aluminum powder is expressed using the following formula:

[0052] ;

[0053] in, Represents the surface activity function of aluminum powder, represents the surface activity of aluminum powder, the formula is: ; For the Arrhenius term; is the reaction activation energy; is the gas constant; is the temperature field, representing the time The temperature at , in Kelvin; is the specific surface area of ​​aluminum powder, that is, the surface area of ​​aluminum powder per unit mass. The larger the value, the more reaction interfaces there are and the higher the reaction rate of aluminum powder. is the aluminum powder concentration; is the concentration of water; The surface energy of aluminum powder represents the energy of the aluminum-water interface and affects the difficulty of aluminum dissolution. The higher the surface energy, the easier it is for aluminum powder to react. is the Boltzmann constant; For time The critical nucleus radius of aluminum powder at , reflects the thickness of the aluminum oxide film and determines the activity of aluminum: Increase, indicating that the oxide film of aluminum powder is thicker. will decrease, indicating that the reactivity of aluminum powder decreases; if Decrease means that the oxide film of aluminum powder is damaged or activated. , which means that the hydrolysis reaction of aluminum powder is more likely to occur; is the reaction rate constant, dimensionless, and is a set value, representing the maximum aluminum powder reaction rate without an energy barrier; For time.

[0054] Specifically, in this equation, Represents the rate of change of aluminum powder concentration over time, that is, the amount of aluminum consumed per unit volume of reaction solution per unit time. The negative sign indicates that the aluminum powder concentration decreases over time, which means that aluminum is being consumed continuously. As a reaction rate constant, it determines the maximum aluminum powder reaction rate without an energy barrier and is a set value related to the type of aluminum powder and experimental conditions. Since the rate of aluminum hydrolysis is controlled by temperature, the equation introduces the Arrhenius term , which describes the exponential relationship between the reaction rate and temperature, where is the activation energy of the reaction, which determines the energy barrier that the reactant molecules must overcome, and is the gas constant. According to the Arrhenius law, when the temperature When the temperature rises, the value of the exponential term approaches 1, which increases the reaction rate. However, at low temperatures, the term approaches zero, which inhibits the reaction. The reaction rate of aluminum powder was further modified to reflect the effect of its surface activity. Depend on It shows the influence of aluminum powder surface energy, temperature and oxide film thickness on the reaction activity. Determines the energy state of the aluminum-water interface. The higher it is, the weaker the bonding force between aluminum atoms is, and water molecules are more likely to attack the aluminum surface, making the reaction more likely to occur. When it is higher, When it approaches 1, it means that the surface of aluminum powder is in a highly active state. When descending, It gradually decreases, indicating that the aluminum powder surface tends to be passivated and the reactivity decreases. On the other hand, the function also includes the critical nucleus radius , which describes the thickness of the oxide film, that is, the growth of the oxide layer on the aluminum surface. The increase means that the oxide layer on the surface of the aluminum powder becomes thicker, and it is difficult for water molecules to penetrate the oxide layer to reach the active aluminum, thereby reducing the reaction rate. decreases, resulting in a slower overall response. When the temperature decreases, it means that the oxide layer is thinner or even cracked, and water molecules can directly contact the aluminum surface. Close to 1, the reaction rate of aluminum powder increases significantly.

[0055] The equation also includes the specific surface area of ​​aluminum powder and aluminum powder concentration Specific surface area represents the surface area of ​​aluminum powder per unit mass, and its size directly affects the contact area between aluminum powder and water. A larger specific surface area means more reaction sites, which increases the reaction rate, while a smaller specific surface area may limit the diffusion of water molecules and reduce the reaction rate. In addition, the concentration of aluminum powder Directly determines the amount of aluminum available for reaction in the system. When it is high, the reaction rate is faster, and when As the concentration of water decreases, the reaction gradually tends to terminate. It also affects the reaction rate. The hydrolysis of aluminum is a first-order or pseudo-first-order reaction. When the water concentration is much higher than the aluminum powder concentration, the water concentration can be approximately considered a constant. However, at a higher aluminum powder load, the water concentration may become a limiting factor of the reaction. Therefore, the equation also includes To ensure the accuracy of calculations.

[0056] Compared with the traditional aluminum hydrolysis reaction rate model, the creativity of this equation is reflected in many aspects:

[0057] First, it introduces the surface activity function As a correction factor, the model can dynamically adjust the reaction rate of aluminum powder, avoiding the problem of ignoring the change of the surface state of aluminum powder in the traditional empirical model. The influence of the oxide film on the reactivity is reflected, which is an important factor not included in the previous model. The oxide film of aluminum powder changes continuously during the hydrolysis process. If its evolution is not considered, it will lead to large prediction errors. The equation of the present invention combines and , effectively improving the prediction accuracy. In addition, the model comprehensively considers multiple variables such as the surface energy, specific surface area, and temperature of aluminum powder, making it applicable to different types of aluminum powder materials and reaction conditions, and improving the adaptability and stability of the model.

[0058] Example 4: The hydrogen production rate prediction equation is expressed using the following formula:

[0059] ;

[0060] in, is the gas escape coefficient; is the reaction rate of aluminum powder; is the stoichiometric coefficient, derived from the aluminum hydrolysis reaction: , where 2 mol of aluminum will produce 3 mol of hydrogen, so the hydrogen production rate is the aluminum consumption rate times; is the molar mass of hydrogen; is standard atmospheric pressure; is the Gibbs free energy change, if , indicating that the reaction proceeds spontaneously, is approximately 0, then , that is, the reaction completely releases hydrogen; if , indicating that the reaction is not spontaneous, If it is close to 1, the term approaches 0, which means that almost no hydrogen is released; For time Response pressure at the time; For time The predicted hydrogen rate at .

[0061] Specifically, during the aluminum hydrolysis reaction, the aluminum consumption directly determines the hydrogen release rate. Since the stoichiometric relationship is , that is, every 2 moles of aluminum powder will produce 3 moles of hydrogen, so there is a fixed proportional relationship between the hydrogen release rate and the aluminum consumption rate, that is, . This term ensures that the hydrogen production rate can be directly derived from the reaction rate of aluminum, so that the model can provide continuous hydrogen release predictions in combination with the aluminum powder kinetic equation. However, relying solely on the aluminum consumption rate cannot fully describe the actual release of hydrogen, because factors such as the reversibility of the reaction, bubble growth, and escape behavior will affect the final generation of hydrogen. Therefore, the present invention introduces multiple correction terms to enable the model to more accurately reflect the complexity of the aluminum hydrolysis reaction. The spontaneity of the reaction determines the degree of hydrogen release. If the change in the Gibbs free energy of the aluminum hydrolysis reaction If it is negative, it indicates that the reaction can proceed spontaneously and the release of hydrogen is not thermodynamically limited; but if If it is positive, it means that the reaction is not spontaneous and the release of hydrogen will be greatly inhibited. Therefore, the present invention introduces a correction term into the hydrogen production rate equation: To describe the effect of Gibbs free energy on hydrogen release. When , the correction term tends to 1, which means that the reaction can fully release hydrogen; When , this term tends to 0, indicating that the release of hydrogen is almost completely inhibited. This correction term ensures that the model can be applied to different reaction conditions, especially when the temperature changes greatly, and can effectively adjust the hydrogen release rate, so that the system can be dynamically optimized based on thermodynamic principles.

[0062] However, even if the reaction is thermodynamically spontaneous, the release rate of hydrogen is still limited by the gas escape kinetics. In the process of hydrolyzing aluminum to produce hydrogen, hydrogen is usually generated in the form of tiny bubbles, and the growth, aggregation and escape behavior of the bubbles will affect the final release efficiency of hydrogen. If the bubbles stay in the liquid phase for too long, the local hydrogen concentration will increase, thereby reducing the reaction rate of aluminum powder, and may even cause bubble aggregation to hinder fluid circulation. Therefore, the present invention introduces the gas escape coefficient to describe the ability of hydrogen to transfer from the liquid phase to the gas phase. This coefficient consists of two parts, Represents the thermal motion rate of hydrogen molecules, indicating that the higher the temperature, the faster the average motion speed of hydrogen molecules, making it easier for them to escape from the liquid phase and increase the release rate of hydrogen. The effect of pressure on hydrogen escape is described, indicating that under high pressure, the growth of bubbles is inhibited, which reduces the release rate of hydrogen, while under low pressure, bubbles can expand and detach faster, thus promoting the release of hydrogen. Therefore, the introduction of the gas escape coefficient enables the model to accurately describe the release behavior of hydrogen under different pressure and temperature conditions, improving the prediction accuracy.

[0063] Compared with the traditional hydrogen production rate model, the equation of the present invention has stronger adaptability and accuracy. The traditional model usually only derives the release rate of hydrogen based on the consumption rate of aluminum, and fails to consider the spontaneity of the reaction and the influence of bubble dynamics. Therefore, under high temperature and high pressure or high reaction rate conditions, the prediction results often have large errors. The equation of the present invention introduces the Gibbs free energy correction term, so that the hydrogen release rate can dynamically adapt to different thermodynamic conditions to ensure the universality of the model. At the same time, the introduction of the gas escape coefficient enables the hydrogen release rate to adapt to different pressure and temperature conditions, making the model more in line with the actual reaction environment. In addition, the equation can also be adjusted in real time in combination with the feedback data of the intelligent control unit, so that the control parameters such as the stirring rate and the fluid circulation mode can be optimized according to the change of the hydrogen release rate, thereby improving the overall operation efficiency of the system. In practical applications, the hydrogen production rate prediction equation can not only be used to calculate the release rate of hydrogen, but also provide key data for the intelligent control system, so that the system can dynamically adjust the reaction conditions based on parameters such as real-time monitoring of pressure, temperature and aluminum powder consumption rate. For example, when the system detects that the hydrogen release rate is lower than the predicted value, the stirring rate can be appropriately increased to promote the bubbles to separate from the liquid phase and improve the hydrogen release efficiency; and when the system detects that the hydrogen release rate is too fast, which may cause the pressure in the reactor to increase, the stirring intensity can be appropriately reduced to extend the residence time of the bubbles to reduce the impact of instantaneous gas accumulation on the stability of the system. In addition, the equation can also be used to optimize the feeding strategy of aluminum powder so that the addition rate of aluminum powder can match the release rate of hydrogen, thereby ensuring that the system always maintains a stable hydrogen production capacity during long-term operation. Therefore, the hydrogen production rate prediction equation of the present invention not only improves the calculation accuracy of the hydrogen release rate, but also enhances the intelligent control capability of the system, making the process of hydrogen production by hydrolysis of aluminum more efficient, stable and controllable, and providing strong theoretical support for the application of the hydrogen energy industry.

[0064] Example 5: The bubble growth equation is expressed using the following formula:

[0065] ;

[0066] in, It is the total pressure composed of hydrostatic pressure and surface tension pressure; is the bubble radius; is the liquid density; is the surface tension of the reaction solution; is the gravitational acceleration constant; is the liquid level height.

[0067] Specifically, the core of the equation is , that is, the radius growth rate of the bubble, which determines the growth process of the bubble in the liquid phase and affects the final escape behavior. If the bubble grows too fast, it may cause the bubble to burst before it grows fully, blocking the hydrogen escape path and affecting the overall hydrogen production rate; if the bubble grows too slowly, it will cause the bubble to stay in the liquid phase for too long, hindering the release of hydrogen. Therefore, the bubble growth equation of the present invention introduces multiple influencing factors so that the bubble growth rate can accurately reflect the changes under different working conditions. This term comes from the Rayleigh-Plesset equation in fluid mechanics, which describes how the growth of bubbles in a liquid is affected by surface tension and liquid density. Represents the energy state of the gas-liquid interface. Higher surface tension means that it is more difficult for bubbles to form, so the molecular part of this term contains , indicating that greater surface tension will inhibit the growth of bubbles. Represents the liquid phase density, which determines the buoyancy and inertia of the bubble. A larger liquid phase density will reduce the growth rate of the bubble, so the denominator of this term contains Overall, this section describes how bubble growth is affected by the physical properties of the liquid and ensures that the formula is applicable to different types of liquid environments. This term describes the rate at which the volume of the bubble increases. represents the release rate of hydrogen, that is, the volume of hydrogen generated per unit time, and represents the surface area of ​​the bubble, so Reflects the hydrogen flux per unit surface area. Since the growth of bubbles is a process of volume accumulation, this term is taken as the cube root so that the formula can accurately describe the expansion trend of the bubbles. If the hydrogen release rate is high, the value of this term increases, which means that the bubbles can expand faster; if the hydrogen release rate is low, the growth rate of the bubbles slows down. This part ensures that the size growth of the bubbles is consistent with the hydrogen generation rate, so that the model can accurately predict the growth behavior of the bubbles.

[0068] also, This term describes the inhibitory effect of pressure on bubble growth, where Represents the total pressure on the bubble, including the hydrostatic pressure and surface tension pressure . Hydrostatic pressure term Represents the liquid level height As the depth of the liquid increases, the hydrostatic pressure increases, making it more difficult for bubbles to grow. Represents the additional pressure on the bubble interface. Smaller bubbles are subject to higher surface tension pressure due to their larger surface curvature. Therefore, in the early stages of growth, the bubble growth rate is slower. As the bubble grows larger, the surface tension pressure gradually decreases, accelerating the growth of the bubble. Since pressure has an exponential inhibitory effect on bubble growth, this term uses an exponential function , ensuring that when the pressure is high, the term tends to 0, so that the growth rate of the bubble decreases, and when the pressure is low, the term tends to 1, so that the growth rate of the bubble accelerates. Compared with the traditional bubble growth model, the equation of the present invention has stronger physical rationality and adaptability. The traditional empirical model usually only considers the relationship between the growth rate of the bubble and the hydrogen release rate, while ignoring the influence of the liquid phase density, surface tension and hydrostatic pressure on the bubble, resulting in low prediction accuracy under different working conditions. The equation of the present invention combines fluid mechanics, gas dynamics and surface tension theory, so that the model can not only be applied to standard conditions, but also can provide high-precision bubble growth prediction under different temperatures, pressures and fluid environments. In addition, the equation can also be combined with an intelligent control system, so that control strategies such as stirring rate and liquid phase circulation mode can be optimized in real time according to the growth state of the bubble, thereby improving the release efficiency of hydrogen. In practical applications, the bubble growth equation can be used to optimize the stirring strategy so that the stirring rate can be dynamically adjusted according to the size distribution of the bubble. For example, in the early stage of the reaction, when the bubbles are small, the system can increase the stirring rate appropriately to promote the merging of bubbles and allow hydrogen to escape faster; in the later stage of the reaction, when the bubbles are large and numerous, the stirring rate can be appropriately reduced to avoid excessive shearing that causes bubble rupture and blocks the hydrogen release path. In addition, this equation can also be used to optimize the liquid level design of the reactor. By adjusting the liquid level height , controlling the hydrostatic pressure of the bubbles so that they can grow within the optimal pressure range and improve the hydrogen release efficiency. In addition, the model can also be combined with the hydrogen production rate prediction equation to synchronize the hydrogen release rate with the bubble growth rate, ensuring that the system maintains a stable hydrogen production capacity during long-term operation.

[0069] Example 6: The mass transfer and heat transfer model is expressed using the following formula:

[0070] ;

[0071] in, is the number of bubbles per unit volume; is the thermal diffusion coefficient, ; is the reaction enthalpy; is the volume of a single bubble; is the temperature field; is the dynamic viscosity of the reaction liquid; is the specific heat capacity of the reaction solution; is the thermal conductivity of the reaction liquid; is the volume of the reaction vessel.

[0072] Specifically, the change of temperature field is determined by multiple factors. The heat diffusion term describes the heat conduction effect inside the reaction liquid, while the heat source term reflects how the chemical energy released during the aluminum powder reaction is converted into heat energy and affects the overall temperature distribution of the system. The heat diffusion term is controlled by the thermal diffusion coefficient, which is The thermal conductivity of the liquid phase ,density and specific heat capacity Joint decision, i.e. . This parameter reflects the heat transfer capacity of the liquid, and its size determines how the reaction heat diffuses in the liquid phase, thereby affecting the uniformity of the system temperature. If the thermal diffusion coefficient is large, the heat released by the reaction can quickly diffuse to the entire liquid phase, making the temperature field more uniform and avoiding the problem of local excessive temperature; if the thermal diffusion coefficient is low, it may cause local overheating, causing the oxide film on the surface of the aluminum powder to form too quickly, reducing the activity of aluminum. Therefore, the present invention uses this model to calculate the spatiotemporal distribution of the temperature field to ensure that the system can efficiently produce hydrogen while controlling the temperature by optimizing the stirring rate, flow field distribution and other means to keep the reaction in the best working state. On the other hand, the hydrolysis reaction of aluminum will release a large amount of reaction heat, and the heat comes from the reaction enthalpy. , which represents the heat released per unit mole of aluminum when reacting. When the temperature increases, it means that more aluminum powder is consumed per unit time, which leads to an increase in reaction heat. This term reflects the total amount of heat released instantaneously. However, simply calculating the total amount of reaction heat is not enough to describe the change in the temperature field, because hydrogen is generated in the form of bubbles during the reaction, and the volume, number and distribution of the bubbles will directly affect the temperature field. Therefore, the present invention further considers the number of bubbles per unit volume. and its influence to accurately describe the heat transfer process of bubbles in the liquid phase.

[0073] Number of bubbles per unit volume The hydrogen release rate Determined by the bubble volume The impact of This relationship is derived from the growth dynamics of the bubbles, indicating that when the hydrogen generation rate is high, the number of bubbles increases, thus affecting the temperature distribution of the liquid phase. In addition, the model also takes into account the dynamic viscosity of the liquid and surface tension The influence of the bubble distribution on It reflects the stability of bubbles under the balance of fluid resistance and surface tension. This term shows that bubbles grow slowly in a high viscosity environment, while bubbles are more likely to form and aggregate in a low surface tension environment. Therefore, the distribution of bubbles in the liquid not only affects the release rate of hydrogen, but also affects the change of local temperature, which further affects the reaction rate. Therefore, the temperature field equation of the present invention is introduced by To correct the heat transfer effect of bubbles, the model can more accurately describe the thermal diffusion behavior of bubbles in the liquid phase and optimize the temperature control strategy of the system. In addition, the growth and distribution of bubbles also affect the heat transfer coefficient, which in turn affects the overall temperature distribution of the reaction liquid. Since the presence of bubbles will affect the local fluid circulation, especially in the bubble aggregation area, the local temperature may rise, so the model is This term describes how the volume fraction of bubbles affects the change in temperature field. This term shows that when the radius of the bubble Increase, or the number of bubbles When the number of bubbles increases, it means that the proportion of gas phase in the liquid increases, affecting the distribution of heat. If the bubbles gather excessively, it may cause abnormal increase in local temperature, thus affecting the activity of aluminum powder.

[0074] Therefore, the heat transfer model of the present invention can accurately predict the thermal diffusion effect of bubbles, so that the intelligent control system can adjust the stirring rate, optimize the flow field structure, ensure uniform temperature distribution, and improve hydrogen production efficiency. Compared with traditional heat transfer models, the mass transfer heat transfer model of the present invention emphasizes the influence of bubble dynamics on the temperature field during hydrogen release. Traditional heat conduction equations usually only consider the thermal diffusion effect of liquids, while ignoring the growth, aggregation and escape behavior of bubbles during the reaction, which play a vital role in the hydrogen production reaction by hydrolysis of aluminum. If the bubble dynamics are not accurately described, it may lead to local temperature prediction deviations, thereby affecting the adjustment strategy of the intelligent control system. The present invention uses the bubble dynamics parameters and its volume effect The introduction of the temperature field equation enables the system to more accurately predict the temperature distribution, and then optimize the stirring rate, fluid circulation mode and aluminum powder supply strategy to ensure that the system always operates within the optimal reaction temperature range, increase hydrogen production, reduce energy consumption, and extend the service life of the equipment. In practical applications, this mass transfer and heat transfer model can be used to optimize the temperature control strategy of the reactor, so that the system can monitor and adjust the fluid circulation in real time to make the temperature field more uniform. For example, in the early stage of the reaction, due to the high concentration of aluminum powder and large heat release, the system can appropriately increase the stirring rate to enhance the diffusion of heat and prevent local temperature from being too high. In the later stage of the reaction, the hydrogen release rate decreases and the number of bubbles decreases. The system can reduce the stirring intensity to reduce unnecessary energy consumption and improve the overall energy efficiency of the reaction. In addition, the model can also be used to optimize the design of the reactor, such as adjusting the shape, position and rotation mode of the stirring blade to maximize the heat conduction efficiency, while ensuring that the bubbles are evenly distributed to avoid the problem of excessive temperature gradient caused by bubble aggregation.

[0075] Example 7: The flow field distribution model is expressed using the following formula:

[0076] ;

[0077] in, is the reaction pressure gradient; is the thermal expansion coefficient of the reaction liquid; is the vertical unit vector, pointing in the direction of gravity; is the specific volume, which indicates the volume occupied by the unit mass of the reaction liquid. The larger it is, the smaller the density of the reaction liquid is. is the unit vector of the bubble movement direction, which is approximated as the upward floating direction in the case of low stirring or natural convection, and is the opposite direction of gravity. ; is the velocity distribution of the flow field.

[0078] Specifically, in this model, the movement of the fluid is first affected by the pressure gradient. During the reaction, the continuous release of hydrogen will cause the pressure in the local area to change, causing the fluid to flow from the high-pressure area to the low-pressure area. It is one of the main driving forces affecting the flow field and determines the overall circulation pattern of the liquid phase in the reactor. However, pressure-driven flow is usually affected by fluid viscosity. The high viscosity fluid will reduce the flow speed, causing the fluid to be retained in a local area, affecting the full contact between aluminum powder and water. Item, so that the velocity of the fluid can dynamically adapt to the pressure changes during the reaction process, and combined with the intelligent control unit to adjust the stirring rate, so as to minimize the flow resistance and improve the mass transfer efficiency. In addition, the pressure gradient item can also be used to predict the bubble aggregation area, and optimize the movement path of the bubbles through the control system to prevent excessive accumulation of hydrogen in local areas and affect the stability of the reaction. In addition to the flow driven by the pressure gradient, the flow field distribution model of the present invention also considers the effect of thermal buoyancy on fluid movement. Since the hydrolysis of aluminum is a highly exothermic reaction, the increase in local temperature will lead to a decrease in the density of the liquid phase, thereby producing a buoyancy effect and causing the fluid to convect. This process is caused by the thermal expansion coefficient. Control, its expression It reflects the driving force of temperature difference on fluid flow. As the reaction proceeds, the temperature field distribution will change. In the high-temperature area, the thermal buoyancy is enhanced, causing the fluid to rise, while the fluid in the low-temperature area will fall, thus forming a stable natural convection. This phenomenon helps to enhance the mixing effect of aluminum powder and water, increase the reaction rate, and accelerate the release of hydrogen. However, if the thermal buoyancy is too strong, it may cause the rapid rise of bubbles, causing hydrogen to escape prematurely before it is fully grown, reducing the overall hydrogen production efficiency. Therefore, the flow field distribution model of the present invention monitors the changes in the temperature field in real time and optimizes the stirring strategy, so that the effect of thermal buoyancy can be reasonably controlled, the temperature is evenly distributed, and local overheating or local cooling is avoided, thereby ensuring that the system always operates under optimal reaction conditions.

[0079] During the aluminum hydrolysis reaction, the formation, growth and movement of bubbles have a significant impact on the fluid flow. Therefore, the flow field distribution model of the present invention also introduces a bubble dynamics term to describe the driving effect of bubble growth on the fluid. Since hydrogen is generated in the form of bubbles during the reaction and gradually grows in the liquid phase, the movement of bubbles will cause disturbances in the liquid phase, thereby affecting the overall distribution of the flow field. This model is based on This term describes the contribution of the expansion of the bubble per unit volume to the fluid flow. represents the number of bubbles per unit volume, represents the growth rate of the bubble radius, represents the direction of movement of the bubbles. Usually, bubbles float upward when there is low stirring or natural convection, so it can be approximated as the opposite direction of gravity, that is, . The introduction of this item enables the model to accurately predict the movement trajectory of bubbles in the liquid phase, and combined with the intelligent control unit to optimize the fluid circulation, so that hydrogen can be released more evenly, avoiding excessive aggregation or retention of bubbles in local areas, thereby improving the overall efficiency of hydrogen escape. When the system detects that the escape rate of bubbles is too fast, which may lead to a decrease in the efficiency of hydrogen release, the control system can appropriately reduce the stirring intensity to extend the residence time of bubbles in the liquid phase, thereby improving the utilization rate of hydrogen; and when the system detects that the local temperature is too high, which may lead to uneven reaction rate of aluminum powder, the stirring strategy can be adjusted to enhance the uniform diffusion of heat and keep the entire system in the best working state. In addition, the model can also be used to optimize the design of the reactor, such as adjusting the shape, position and rotation mode of the stirring paddle to make the stirring effect more targeted, improve the utilization rate of aluminum powder, and reduce the overall energy consumption of the system. In the early stage of the reaction, since the aluminum powder is not completely evenly distributed, the system can adopt a higher stirring rate to enhance fluid circulation, ensure that the aluminum powder is fully in contact with water, and increase the reaction rate. In the middle of the reaction, due to the increase in hydrogen release rate and the increase in bubbles, the system can reduce the stirring rate to reduce the shear damage of the bubbles and allow hydrogen to escape more smoothly. In addition, the model can also be used to optimize the liquid level control of the reactor so that the liquid depth In the optimal range, the effect of hydrostatic pressure on bubble growth is balanced to improve the bubble escape efficiency. Furthermore, the model can also combine temperature field distribution data to enable the stirring system to be intelligently adjusted according to the thermal convection pattern of the fluid, thereby maximizing the mass transfer and heat transfer efficiency and increasing the overall hydrogen production.

[0080] Example 8: The reaction progress is predicted by combining the flow field velocity distribution and bubble dynamics using the following formula:

[0081] ;

[0082] in, is the surface area of ​​a single bubble; is the particle size of aluminum powder; is the effective diffusion coefficient, and its value range is arrive ; is the cross-sectional area of ​​the reaction vessel; is the time-integrated variable; Represents vector modulus operation; For time The predicted reaction progress.

[0083] Specifically, in this prediction model, Indicates time The reaction progress is calculated by integrating the hydrogen production rate The total amount of hydrogen released is calculated and corrected by combining the flow field velocity, bubble distribution and diffusion effect. The hydrogen release rate is the core determinant of the reaction progress, so This item directly reflects the cumulative amount of hydrogen generated. However, in the actual reaction process, the release of hydrogen is not only controlled by the consumption rate of aluminum powder, but also affected by the formation, growth and escape process of bubbles. If the residence time of hydrogen in the liquid phase is long, or it fails to escape smoothly due to diffusion restriction, then even if the hydrogen production rate predicted by the reaction kinetics is high, the progress of the reaction may still be inhibited. Therefore, the present invention introduces correction factors for bubble dynamics and mass transfer processes to make the prediction results more in line with actual conditions. First, the velocity distribution of the flow field Directly affects the mass transfer efficiency of aluminum powder. In the process of aluminum hydrolysis, water molecules need to diffuse to the surface of aluminum powder, and the hydrogen generated after the reaction is completed needs to diffuse away from the reaction interface. If the flow field velocity is large, it means that the convection effect of the liquid phase is strong, which helps to accelerate the material exchange on the surface of aluminum powder and increase the reaction rate. However, too high a flow rate may cause the agglomeration of aluminum powder or the breakage of bubbles, affecting the stability of hydrogen production. Therefore, this model uses the exponential decay term The effect of flow field on reaction rate is quantified. represents the particle size of aluminum powder, which determines the length of the diffusion path. represents the local fluid velocity, is the effective diffusion coefficient, which reflects the actual diffusion capacity of water molecules in the liquid phase. This exponential term indicates that when the flow rate is large, the diffusion process is enhanced and the reaction progress is accelerated; When the reaction rate decreases, for example, due to the obstruction of the oxide film on the surface of the aluminum powder or the increase of the liquid viscosity, the material transfer is limited, resulting in a decrease in the reaction progress. Therefore, the exponential correction term ensures that the model can adapt to the reaction prediction under different fluid flow conditions, so that the intelligent control system can dynamically adjust the stirring strategy according to the flow field state to improve the mass transfer efficiency. Secondly, the influence of bubble distribution on the reaction progress is another major innovation of the prediction model of the present invention. In the hydrolysis of aluminum, the generation of hydrogen occurs in the form of bubbles, and the surface area of ​​the bubbles is Directly affects the mass transfer rate at the gas-liquid interface. Larger bubbles mean a larger surface area, which facilitates the escape of hydrogen, while smaller bubbles may be retained in the liquid phase, affecting the efficiency of hydrogen release. Therefore, this model is based on This term describes the contribution of bubbles to the overall reaction progress of the reactor per unit time, where represents the number of bubbles per unit volume, is the surface area of ​​a single bubble, is the effective cross-sectional area of ​​the reactor. This ratio reflects the bubble coverage, that is, the distribution of bubbles inside the reactor, and its impact on the overall reaction rate. When the number of bubbles is large, the gas-liquid mass transfer efficiency is improved, hydrogen can escape faster, and the reaction progress is promoted; but if the number of bubbles is too large, it may cause local bubble aggregation, which will hinder the flow of the liquid phase and reduce the mass transfer efficiency. Therefore, this correction term enables the model to optimize the reaction progress prediction according to the real-time growth of bubbles, and dynamically adjust the stirring intensity in combination with the intelligent control system to avoid excessive aggregation or breakage of bubbles and improve the stability of hydrogen release.

[0084] Example 9: Dynamically adjust the stirring rate by the following formula:

[0085] ;

[0086] in; is the set reference speed; is the maximum hydrogen production rate; is the surface activity of the set standard aluminum powder; The calculated time The stirring rate at this time is controlled according to this value.

[0087] Specifically, the stirring rate control equation of the present invention is It consists of multiple correction factors to ensure that the stirring rate can adaptively respond to different reaction conditions. Represents the base speed, that is, the stirring rate set by the system under standard conditions. When the system is in the best working state, near , and when the reaction state changes, the stirring rate will be adjusted according to various correction factors. First, This term describes how the stirring rate changes as the reaction progresses. Represents the degree of aluminum powder consumption and the cumulative release of hydrogen. When the reaction rate is close to 1, that is, when the reaction is close to completion, the stirring rate should be gradually reduced to reduce unnecessary energy consumption and prevent the bubbles from being excessively disturbed and broken or retained in the low reaction rate stage. , at this time, the stirring rate should be kept at a high level to ensure sufficient contact between aluminum powder and water and increase the reaction rate. Therefore, this item ensures that the stirring rate gradually decreases as the reaction proceeds, thereby optimizing the system energy consumption and improving the stability of hydrogen release. Secondly, This term is used to describe the effect of reaction pressure on stirring rate. During the aluminum hydrolysis reaction, the continuous generation of hydrogen will cause the local pressure to rise. Especially in the high hydrogen production rate stage, the excessive accumulation of bubbles may cause the internal pressure of the system to rise significantly, making it difficult for bubbles to escape smoothly. Under high pressure, excessive stirring may cause bubbles to burst prematurely, reducing the hydrogen escape rate and even causing bubble blockage. Therefore, this term adopts an exponential decay form to ensure that when the pressure near (the system's stable pressure threshold), When the value is small, the stirring rate is reduced, which reduces the interference with the bubbles; when the pressure is low, the term is close to 1, making the stirring rate unrestricted. In this way, the correction term ensures that the stirring strategy can dynamically adapt to the pressure state of the system, making the release of hydrogen more stable and avoiding the influence of local pressure fluctuations on the reaction progress.

[0088] In order to match the stirring rate with the hydrogen production rate, the present invention introduces the This term is used to describe the effect of hydrogen generation rate on stirring requirements. Close to the maximum hydrogen production rate of the system When , it indicates that the reaction rate of aluminum powder is high and the system is in the stage of efficient hydrogen production. At this time, appropriately increasing the stirring rate is helpful to enhance the mixing effect of aluminum powder and promote the proper detachment of bubbles. When it decreases, it means that the reaction rate decreases. At this time, excessive stirring may lead to energy waste, so the stirring rate should be reduced accordingly to make the system operate in the optimal energy efficiency state. This correction term ensures that the stirring rate can be adaptively adjusted with the change of hydrogen generation rate to optimize the overall operating efficiency of the system. In addition, This term describes the effect of the diffusion process on the stirring rate. Diffusion is one of the key factors affecting the reaction rate of aluminum hydrolysis. Water molecules need to diffuse to the surface of aluminum powder, and the generated hydrogen needs to diffuse from the liquid phase to the gas phase. If the diffusion coefficient If the diffusion is limited, for example, due to the influence of the oxide film on the surface of the aluminum powder, or due to the low flow rate of the fluid ( If the stirring rate is too high, the mass transfer will slow down, resulting in a decrease in the reaction rate. At this time, the stirring rate should be appropriately increased to enhance convective mass transfer and increase the reaction rate. Therefore, this item ensures that the stirring strategy can be optimized according to the diffusion conditions of the system, so that the mass transfer of the reaction is maintained at the optimal level and the overall efficiency of the system is improved. Finally, This term is used to describe the effect of the surface activity of aluminum powder on the stirring rate. The reaction activity of aluminum powder is affected by the surface oxide film. When the activity is high, the need for stirring is small. When the surface oxide film of aluminum powder is thicker and the activity is reduced, the role of stirring becomes more important. Therefore, this correction term adopts an inverse relationship, that is, when When the temperature decreases, the value of this item increases, which increases the stirring rate, enhances the shearing effect of the liquid on the aluminum powder, promotes the rupture of the oxide film, and improves the activity of the aluminum powder. On the contrary, when the surface activity of the aluminum powder is high, this item tends to 1, so that the stirring rate remains at a normal level. This part ensures that the system can dynamically adjust the stirring strategy according to the state of the aluminum powder, improve the overall efficiency of the reaction, and prolong the high activity time of the aluminum powder.

[0089] The present invention is described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Intelligent control and optimization system in the production of hydrogen by hydrolysis of aluminum, characterized by: The system comprises: a reaction kinetics analysis unit, a fluid field optimization unit and an adaptive intelligent control unit; The reaction kinetics analysis unit is used to construct an aluminum powder reaction rate equation taking into account the surface activity of the aluminum powder according to the aluminum powder activity characterization parameter of the aluminum powder, and obtain the aluminum powder reaction rate; according to the aluminum powder reaction rate, using Gibbs free energy and gas escape coefficient, establish a hydrogen production rate prediction equation to obtain the hydrogen prediction rate; according to the hydrogen prediction rate, construct a bubble growth equation to obtain the bubble growth rate; The fluid field optimization unit is used to analyze the mass transfer and heat transfer coupling effect of the reaction process, establish a mass transfer and heat transfer model, calculate the temperature field under the combined action of reaction heat release and bubble dynamics, and analyze the influence of stirring on fluid movement. By using the fluid permeability and thermal expansion effect, a flow field distribution model is constructed according to the temperature field to obtain the flow field velocity distribution. The flow field velocity distribution is combined with bubble dynamics to predict the reaction progress. The adaptive intelligent control unit is used to dynamically adjust the stirring rate according to the reaction progress, reaction pressure, hydrogen predicted rate, flow field velocity distribution and aluminum powder activity characterization parameters, specifically including: when the reaction progress exceeds a set threshold, reducing the stirring rate; when the reaction pressure increases, resulting in an increased risk of bubble breakage, reducing the stirring rate; when the surface activity of the aluminum powder decreases, increasing the stirring rate.

2. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 1, characterized in that: The parameters characterizing the activity of aluminum powder include: aluminum powder specific surface area, aluminum powder concentration, aluminum powder surface energy, aluminum powder critical nucleus radius and aluminum powder particle size.

3. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 2, characterized in that: The reaction rate equation of aluminum powder is expressed using the following formula: ； in, Represents the surface activity function of aluminum powder, represents the surface activity of aluminum powder, the formula is: ; For Arrhenius term; is the reaction activation energy; is the gas constant; is the temperature field, representing the time The temperature at , in Kelvin; is the specific surface area of ​​aluminum powder, that is, the surface area of ​​aluminum powder per unit mass. The larger the value, the more reaction interfaces there are and the higher the reaction rate of aluminum powder. is the aluminum powder concentration; is the concentration of water; The surface energy of aluminum powder represents the energy of the aluminum-water interface and affects the difficulty of aluminum dissolution. The higher the surface energy, the easier it is for aluminum powder to react. is the Boltzmann constant; For time The critical nucleus radius of aluminum powder at , reflects the thickness of the aluminum oxide film and determines the activity of aluminum: Increase, indicating that the oxide film of aluminum powder is thicker. will decrease, indicating that the reactivity of aluminum powder decreases; if Decrease means that the oxide film of aluminum powder is damaged or activated. , which means that the hydrolysis reaction of aluminum powder is more likely to occur; is the reaction rate constant, dimensionless, and is a set value, representing the maximum aluminum powder reaction rate without an energy barrier; For time.

4. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 3, characterized in that: The hydrogen production rate prediction equation is expressed using the following formula: ； in, is the gas escape coefficient; is the reaction rate of aluminum powder; is the stoichiometric coefficient, derived from the hydrolysis of aluminum: , where 2 mol of aluminum will produce 3 mol of hydrogen, so the hydrogen production rate is the aluminum consumption rate times; is the molar mass of hydrogen; is standard atmospheric pressure; is the Gibbs free energy change, if , indicating that the reaction proceeds spontaneously, is approximately 0, then , that is, the reaction completely releases hydrogen; if , indicating that the reaction is not spontaneous, If it is close to 1, the term approaches 0, which means that almost no hydrogen is released; For time Response pressure at the time; For time The predicted hydrogen rate at .

5. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 4, characterized in that: The bubble growth equation is expressed as follows: ； in, It is the total pressure composed of hydrostatic pressure and surface tension pressure; is the bubble radius; is the liquid density; is the surface tension of the reaction solution; is the gravitational acceleration constant; is the liquid level height.

6. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 5, characterized in that: The mass transfer and heat transfer model is expressed using the following formula: ； in, is the number of bubbles per unit volume; is the thermal diffusion coefficient, ; is the reaction enthalpy; is the volume of a single bubble; is the temperature field; is the dynamic viscosity of the reaction liquid; is the specific heat capacity of the reaction solution; is the thermal conductivity of the reaction liquid; is the volume of the reaction vessel.

7. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 6, characterized in that: The flow field distribution model is expressed using the following formula: ； in, is the reaction pressure gradient; is the thermal expansion coefficient of the reaction liquid; is the vertical unit vector, pointing in the direction of gravity; is the specific volume, which indicates the volume occupied by the unit mass of the reaction liquid. The larger it is, the smaller the density of the reaction liquid is. is the unit vector of the bubble movement direction, which is approximated as the upward floating direction in the case of low stirring or natural convection, and is the opposite direction of gravity. ; is the velocity distribution of the flow field.

8. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 7, characterized in that: The reaction progress is predicted by combining the flow field velocity distribution and bubble dynamics through the following formula: ； in, is the surface area of ​​a single bubble; is the particle size of aluminum powder; is the effective diffusion coefficient, and its value range is arrive ; is the cross-sectional area of ​​the reaction vessel; is the time-integrated variable; Represents vector modulus operation; For time The predicted reaction progress at .

9. The intelligent control and optimization system for producing hydrogen by hydrolysis of aluminum as claimed in claim 8, characterized in that: The stirring rate is adjusted dynamically by the following formula: ； in; is the set reference speed; is the maximum hydrogen production rate; is the surface activity of the set standard aluminum powder; The calculated time The stirring rate at this time is controlled according to this value.

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