Automatic controlled metal hydride reactor

Abstract

The invention relates to a metal hydride reactor comprising a masonry connection element (1), a solenoid valve (2), a pressure transmitter (3), a thermocouple (4), a module (5), rod connection elements (6), liquid fluid inlet (7), liquid fluid outlet (8), and a casing (9) units.

Description

[0001] AUTOMATIC CONTROLLED METAL HYDRIDE REACTOR

[0002] TECHNICAL FIELD

[0003] Metal hydride reactors are technological systems used to provide hydrogen storage and release. These systems consist of hydrogen storing metal hydride material, reactor, cooling and heating system, electronic control unit and environmental elements. Metal hydrides, one of the most important components of the system, are reliable and efficient materials used especially in hydrogen storage technologies.

[0004] Invention is concerned with:

[0005] • The structure, properties and performance of metal hydrides, and the synthesis, characterization and improved storage capacity of a material developed in this regard,

[0006] • At the same time, studies on reactor design and production, hydrogen charge / discharge kinetics, temperature and pressure control systems, theoretical and experimental analysis of process parameters and studies to increase metal hydride reactor efficiency,

[0007] • Storing hydrogen produced from sources such as solar or wind energy,

[0008] • Heat transfer, cooling systems and temperature control of reactors,

[0009] • Development of an electronic control unit to ensure the operation and control of metal hydride reactors under desired conditions and efficiency,

[0010] • Mathematical modeling, simulation and data analysis studies to understand and optimize the complex heat and mass transfer and chemical reactions that occur during hydrogen charging / discharging processes, which are an important factor in the design of metal hydride reactors.

[0011] Metal hydride reactor systems play an important role, especially in sustainable energy storage and transportation systems. The invention is aimed at the development of a more efficient, safe and economical metal hydride reactor system.

[0012] BACKGROUND

[0013] Decreasing reserves of fossil fuels and increasing environmental damages lead to a growing demand for alternative energy sources in the energy sector. In this context, hydrogen has emerged as a significant alternative energy carrier due to its cleanliness, reliability, efficiency, and lack of environmental harm. In today's era of the hydrogen age, one of the most significant obstacles preventing the widespread use of hydrogen is considered to be the issue of storage.

[0014] Hydrogen gas can be stored in gas, liquid, and metal hydride forms. Due to the low energy density per unit volume of hydrogen in the gas phase, storing it under normal conditions requires large volumes. The challenges associated with gas phase storage are among the major barriers to the widespread adoption of hydrogen energy. Among the solutions proposed for this problem, compressed gas at high pressures (-700 bar) or storage in liquid phase at cryogenic temperatures (-20 K) are prominent. However, both of these methods entail additional costs due to the necessity of maintaining high pressures or cryogenic temperatures. For example, storing 60 liters of hydrogen gas at 17 MPa pressure requires equipment weighing approximately 1 ton and occupying a volume of 2m3. Additionally, if we were to store the same amount of hydrogen in liquid form, it would require equipment weighing around 20 kg, but the process of liquefying hydrogen is very expensive, requiring about one-third of the energy to be obtained for liquefaction.

[0015] Another method for hydrogen storage is through metal hydrides. The process of hydrogen storage in metals occurs at a specific feed pressure and at room temperature or lower. The stored hydrogen remains in a hydride structure until exposed to high temperature or a discharge pressure difference. Therefore, there is increasing interest in metal hydride reactors to overcome these challenges, and further research and innovative storage technologies are needed for the development and industrial-scale implementation of metal hydride storage methods. In conclusion, overcoming the challenges in storage technologies is essential to increase the use of hydrogen as a clean energy source, which can be achieved through industrial solutions and research efforts in scaling up these technologies.

[0016] During the charging and discharging processes of hydrogen with metals, both exothermic and endothermic reactions occur. The reversible nature of these processes allows for a variety of applications.

[0017] Metal hydrides have been proven in numerous engineering applications. Some of these have been commercialized, while others are still in the research and development stage. However, engineering applications of metal hydrides in practical systems generally encompass thermal systems, energy systems, hydrogen purification, semiconductors, and other fields. Within this scope, integrated systems utilizing metal hydrides, such as thermal-driven metal hydride compressors, heat pumps, refrigerators, and air conditioning systems, have been developed.

[0018] Metal hydrides are also used to purify hydrogen for the semiconductor industry, where high-purity hydrogen is required. Ni-Metal Hydride batteries, which operate with hydrogen, have become commercially available.

[0019] SUMMARY OF THE INVENTION

[0020] The purpose of the invention is to provide a hydrogen discharge system capable of supplying hydrogen at the required flow rates for fuel cells. The system consists of 3 groups and 15 modules. When the system is first activated, the modules of the 1st group become active; as the demand for hydrogen increases, the modules of the 2nd and 3rd groups are sequentially activated. Thus, the hydrogen flow can be automatically adjusted to correspond to the dynamic behavior of the fuel cell.

[0021] Another objective of the invention is to facilitate the initial start-up and shutdown of fuel cells used in automotive, forklift, and submarine applications, as well as to quickly respond to variable load conditions. This enables the system to be adapted to a wide range of applications and to rapidly adapt to different conditions.

[0022] Another objective of the invention is to increase the industrial use of fuel cell technology in applications such as automotive and submarines, where fuel cells can operate effectively. This aims to broaden the scope of hydrogen storage and utilization in various fields.

[0023] The metal hydride reactor has been developed into a fully automatic and compact system, aiming to elucidate the fundamental mechanism of hydrogen charging / discharging and achieve the best reactor design. Simultaneously, the goal is to enhance the structuring and knowledge transfer regarding hydrogen charging / discharging methods and contribute to practical applications. Given that one of the primary objectives of the invention is for the automotive sector, a compact design was pursued considering ease of use and cost-effectiveness. The compact water- cooled metal hydride reactor, consisting of a total of 15 modules, capable of performing hydrogen charging / discharging processes and responding to instantaneous reactions easily, is designed according to a working pressure of 60 bar, with material selection based on this parameter. Each module comprises 25 pellets of storage material. In the developed 15-module reactor with 375 pellets, the weight of each pellet has been optimized to 40 grams. Additionally, a control unit has been developed within the scope of the work, adding a separate technical effect to the invention.

[0024] The novelty of the invention lies in its inclusion of a hydrogen charging / discharging system specifically designed to meet the hydrogen flow requirements of fuel cells, particularly addressing the needs of fuel cells in terms of hydrogen flow rates. The system comprises 3 groups and 15 modules, allowing for adaptability to the dynamic behavior of the fuel cell through the sequential activation of these modules. Specifically designed to respond to variable load conditions and the start-up and shutdown processes of the power unit, especially for automotive applications, this design offers a new approach for more effective utilization of fuel cell technology, particularly in the automotive sector.

[0025] LIST OF FIGURES

[0026] Figure 1. General view of the metal hydride reactor

[0027] Correspondence of the numberings given in the figure:

[0028] 1 . Sleeve connector

[0029] 2. Solenoid valve

[0030] 3. Pressure transmitter

[0031] 4. Thermocouple

[0032] 5. Module

[0033] 6. Rod connectors

[0034] 7. Liquid fluid inlet

[0035] 8. Liquid fluid outlet

[0036] 9. Hive

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] The metal hydride reactor comprises a sleeve connector (1 ), a solenoid valve (2), a pressure transmitter (3), a thermocouple (4), a modul (5), rod connectors (6), a aliquid fluid inlet (7) , liquid fluid outlet (8) and a casing (9).

[0039] The sleeve connection element (1 ) serves as the connection point for hydrogen charging / discharging processes and engineering applications.

[0040] The solenoid valve (2) is the system that allows for hydrogen charging / discharging processes in the module groups. The pressure transmitter (3) is used to measure the gas pressures inside during hydrogen charging / discharging processes.

[0041] The thermocouple (4) is used to measure the module wall temperature during hydrogen charging / discharging processes.

[0042] The module (5) consists of durable metal beds capable of holding hydrogen storage materials up to 60 bar pressure. Within the invention, there are three module groups. Each group accommodates 5 modules, totaling 15 modules. When the system is first activated, the modules of the 1st group become active; as the demand for hydrogen increases, the modules of the 2nd and 3rd groups are sequentially activated. The activation or deactivation of module groups (5) is performed through an electronic control unit. The electronic control unit comprises a microprocessor and the software within this microprocessor as part of the system. Thus, the hydrogen flow can be automatically adjusted to correspond to the dynamic behavior of the fuel cell. The compact water-cooled metal hydride reactor, capable of performing hydrogen charging / discharging processes with a total of 15 modules and easily responding to instantaneous reactions, is designed according to a working pressure of 60 bar, with material selection based on this parameter. Each module comprises 25 pellets of storage material. In the developed 15-module reactor with 375 pellets, the weight of each pellet has been optimized to 40 grams.

[0043] The rod connection elements (6) are systems that provide connection between modules.

[0044] The liquid coolant inlet (7) is the entry point for the cold / hot coolant during hydrogen charging / discharging processes.

[0045] The liquid coolant outlet (8) is the exit point for the cold / hot coolant during hydrogen charging / discharging processes.

[0046] The casing (9) is the system through which the liquid coolant inlet / outlet is provided during hydrogen charging / discharging processes, facilitating the cooling or heating of the modules.

[0047] The fact that the metal hydride reactor, the subject of the invention, consists of modules (5) and can supply hydrogen gas at instantaneous required flow rates can be considered the most significant technical effect. Each module (5) contains a storage material that enables the storage and release of hydrogen. The mentioned hydrogen storage material is an ENG (enhanced natural graphite) enhanced and copper-coated material to improve their thermal conductivity. In the system, temperatures are measured using thermocouples (thermometers) (4), pressures are monitored using pressure transmitters (pressure gauges) (3), and the flow rate of cooling and heating fluids as well as hydrogen gas is measured using flow meters. These measurements are then fed into the electronic control unit integrated with a processor. Signal processing is performed in the control unit to preprocess the data for noise reduction, ensuring accurate data acquisition.

[0048] Metal hydride reactor consists of 15 modules (5). Each of these modules (5) is filled with hydrogen storage material, developed and optimized to weigh 1 kg, comprising Cu-coated and ENG-enhanced LaNi5 powder alloy. To prepare the mentioned copper-coated LaNi5 powders, a solution was prepared by dissolving at least 8 grams and up to 100 grams of copper II sulfate pentahydrate (CU2SO4.5H2O) and a small amount of sulfuric acid (H2SO4) in 500 ml of distilled water at room temperature. Then, commercial metal hydride LaNi5 (99% purity) was added to the solution prepared with different gram amounts as mentioned above, along with 80 grams of unground and 80 grams of surface area-enhanced powders, and milled for 5 hours. After optimizing the solution with a magnetic stirrer for 90 seconds, the copper- coated powders were filtered twice with ethanol (99% purity, C2H5OH), rinsed with distilled water, and dried at room temperature. Thus, the material of LaNis coated with copper solution was prepared.

[0049] For the synthesis of expanded natural graphite (ENG), a mixture consisting of 5 g of Ammonium Persulfate (98% (NH4)2S20s) and 3 ml of sulfuric acid (98% H2SO4) was sonicated for 10 minutes. Then, 1g of natural graphite (NG) was added to the mixture and stirred with a magnetic stirrer for 5 minutes. The mixture was left at room temperature for 24 hours. Subsequently, it was washed several times with distilled water and dried in a vacuum oven at 85°C for 24 hours. Then, a thermal shock treatment was applied in a muffle furnace at 900°C for 60 seconds to complete the process. At this high temperature, intercalated (trapped within the graphite layers) materials can decompose, allowing the graphite layers to expand further. The resulting materials are called expanded natural graphite (ENG).

[0050] The powders developed as described above, consisting of specific amounts of at least 8 g and up to 100 g of Cu-coated powders and at least 1 % and up to 20% ENG, were used to prepare new composite storage materials.

[0051] The metal hydride reactor system includes an electronic control unit for monitoring and controlling the system. This electronic control unit incorporates sensors for monitoring various parameters. Thermocouples (4) are used for temperature measurement, pressure transmitters (3) for pressure measurement, and flow meters for measuring the flow rates of cooling and heating fluids as well as hydrogen gas. Data from these sensors are collected and recorded on a system data acquisition card within the electronic control unit. This data acquisition card allows for simultaneous data collection, signal processing on the controller, and simultaneous monitoring of the collected data. Additionally, proportional-integral-derivative (PID) control of the proportional drive elements in the system is also facilitated by the data acquisition card.

[0052] WORKING PRINCIPLE OF THE INVENTION

[0053] The charging / discharging processes of hydrogen with metal are expressed by the following equation:

[0054] M + X / 2H2^MHX+AH

[0055] Here, M and H represent the metal and hydrogen, respectively, x is a coefficient, and AH symbolizes the reaction enthalpy. Since the charging and discharging processes of hydrogen in metal hydride reactors involve exothermic and endothermic reactions, heat needs to be appropriately removed from or added to the system; otherwise, the reaction may stop or slow down. The required amount of heat is determined by the enthalpy of the reaction. Reaction kinetics are significantly influenced by the rate of heat transfer. The performance of a metal hydride reactor is primarily affected by the reactor's low thermal conductivity and geometric parameters, which limit heat transfer. Therefore, designing an efficient reactor aims to achieve faster filling and emptying rates and reach a higher weight ratio (metal hydride mass / empty reactor mass).

[0056] Charging Mechanism:

[0057] Considering the formation of metal hydride, several interactions occur during the dissolution of hydrogen in the main lattice of a metal. Firstly, Van der Waals forces, resulting in approximately 10 kJ / mol H, lead to physical adsorption when a hydrogen molecule approaches the metal surface. Here, the adhesion of all molecules to the surface depends on parameters such as the collision velocity, the geometry of the metal, and the surface area involved in the collision. The equilibrium distance for physically adsorbed hydrogen molecules is approximately 0.2 nm from the metal surface. Subsequently, the molecule dissociates into two H atoms chemically absorbed on the surface. At this stage, the energy of the chemical bond is 30-60 kJ / mol H. In fact, due to their unsaturation, these areas have a higher chemical potential compared to a bulk area or only a surface area, exhibiting greater reactivity. In the next step, atomically chemically absorbed hydrogen diffuses from the layers beneath the surface by overcoming an activation barrier of approximately 40 kJ / mol. Then, hydrogen spreads in the metal by overcoming another barrier of about 10 kJ / mol.

[0058] Sample Application:

[0059] In the current era of hydrogen, metal hydrides have found applications, particularly in forklifts, submarines, and vehicles. In automotive applications using fuel cells, during the initial start-up, hydrogen release from the metal hydride will be facilitated by an external heat source, other than the hydrogen needed by the fuel cell. Subsequently, hydrogen release at desired rates can be achieved using the exhaust heat of the fuel cell. Proton Exchange Membrane (PEM) fuel cells commonly used in vehicles operate at temperatures ranging from 70-80°C. Since hydrogen physically adheres to the metal, providing a small amount of energy (e.g., the temperature of water at 30-60°C) will suffice for hydrogen release. Thus, using the exhaust heat of the fuel cell, hydrogen release can be facilitated through an endothermic reaction. In case of a decrease in stored hydrogen, the driver can perform hydrogen refueling while the storage process is underway. Consequently, the metal hydride reactor charges the stored hydrogen, and the heat generated as a result of the exothermic reaction is removed by the coolant fluid. As the vehicle is driven, hydrogen is directed to the fuel cell, where it reacts with oxygen to generate electrical energy. The produced electrical energy can power the electric motor, enabling the vehicle's movement.

[0060] The invention can be utilized in the field of hydrogen storage. Metal hydride reactors provide an environment where hydrogen can be absorbed and stored. This feature facilitates the use of hydrogen in energy storage systems and the transportation sector.

[0061] The invention can also be used in the field of energy storage. Metal hydride reactors can be used for the storage of hydrogen produced by PEM (Proton Exchange Membrane) electrolyzers, which generate hydrogen from renewable energy sources such as solar and wind power.

[0062] Another potential application of the invention could be in the transportation sector. Metal hydride reactors enable the storage and release of hydrogen for use in the transportation sector. Hydrogen can thus be utilized in fuel cell vehicles and other transport vehicles.

[0063] Another potential application of the invention could be in heat pumps and cooling systems. Metal hydride reactors, when used in heat pumps and cooling systems, can facilitate heat transfer through the absorption and release of hydrogen. This capability can be utilized in industrial cooling and heating applications.

[0064] The invention can also be used for chemical processes. Metal hydride reactors can be utilized to provide hydrogen for use in chemical processes.

[0065] The invention can also find applications in the field of nuclear energy. Metal hydride reactors can be utilized for hydrogen storage and cooling in nuclear energy applications. This can provide a safe and effective hydrogen storage solution in nuclear reactors.

[0066] Another application of the invention could be in electricity generation. Hydrogen can be stored through metal hydride reactors and later utilized for electricity generation. This can be used to provide electricity during periods of high energy demand. In summary, metal hydride reactors offer a wide range of applications, enabling the effective use of hydrogen in energy storage, transportation, and industrial processes.

Claims

CLAIMS1. An automatically controlled metal hydride reactor characterized by comprising a sleeve connector (1 ), a solenoid valve (2), a apressure transmitter (3), a thermocouple (4), a flowmeter, modules containing Cu-coated and ENG-added LaNis powder alloy as hydrogen storage material (5), a rod connector (6), a liquid fluid inlet (7), a liquid fluid outlet (8), a sleeve (9) and; further comprising an electronic control unit performing the activation or deactivation of the modules (5), recording data obtained from the thermocouple (4) for temperature measurement, from the pressure transmitter (3) for pressure measurement, from the flowmeter for measuring the flow rates of cooling and heating fluids and hydrogen gas, synchronizing the data, performing signal processing, and enabling monitoring of the provided data.

2. The automatically controlled metal hydride reactor according to Claim 1 , characterized by comprising 3 module groups, with each module group further comprising 5 modules.

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