1. Field of the Invention
The disclosure relates in general to a one-off and adjustment method of hydrogen releasing from chemical hydride, and more particularly to a method for releasing hydrogen via “contact and non-contact” to switch the reaction “on and off”.
2. Description of the Related Art
Fuel cell is a device capable of converting chemical energy into electrical energy. The fuel cell can generate electrical energy continuously while fuel and oxidant are provided constantly. As to the hydrogen fuel cell, the fuel is hydrogen, and the oxidant is oxygen. The conventional hydrogen production system in a hydrogen fuel is usually designed to include several complicated units, such as the motors, the sensors and logic circuits, for controlling the hydrogen production system.
After hydrogen is released, the product of the hydrolysis reaction of sodium borohydride, namely sodium perborate solution, is extracted from the catalyst bed by separating from hydrogen due to the difference of specific gravities, and the extracted sodium perborate solution is then transported to the spent fuel storage tank 15. Also, hydrogen is discharged through an outlet 161 on the top of the gas liquid separator 16 for use. The pressure sensor 17 positioned on the upper part of the gas liquid separator 16 is able to monitor the pressure of hydrogen instantly. The pressure sensor 17 is also electrically connected to the controller 18.
When the conventional hydrogen production system starts to operate, the controller 18 controls the pump 11 according to the pressure of hydrogen detected by the pressure sensor 17, for further controlling the hydrogen production. For example, when the pressure sensor 17 detects that the pressure of hydrogen is insufficient, the pump 11 transports sodium borohydride solution in the fuel tank 12. Accordingly, the hydrogen production rate and pressure of hydrogen could be adequately adjusted and controlled.
However, those conventional hydrogen production systems as described above all have very complicated mechanical designs with bulky dimensions and weights, which is expansive and not easy to carry for daily use.
The disclosure relates to a one-off and adjustment method of hydrogen releasing from chemical hydride. Hydrogen is generated via “contact and non-contact” between the reactants so as to switch the reaction “on and off”.
According to the first aspect of the present disclosure, a method of hydrogen releasing from chemical hydride is provided. First, at least a hydride powder, a catalyst powder and a water-containing reactant are provided. Any two of the hydride powder, the catalyst powder and the water-containing reactant are then mixed to form a mixture. Next, a contact area between the mixture and the remaining one of the hydride powder, the catalyst powder and the water-containing reactant is adjusted for controlling a hydrogen-releasing reaction. When the mixture and the remaining one is in a contact condition, the hydride powder reacts with the water-containing reactant to bring about the hydrogen-releasing reaction, and the catalyst powder catalyzes the hydrogen-releasing reaction.
The disclosure will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
In the embodiments of the present disclosure, a one-off and adjustment method of hydrogen releasing from chemical hydride is provided. Hydrogen is generated via “contact and non-contact” between the reactants so as to switch the reaction “on and off”. Alternatively, an inhibitor or an inhibiting method could be used for suppressing or terminating the hydrogen-releasing reaction.
The embodiments are provided to demonstrate the one-off and adjustment method of hydrogen releasing from chemical hydride. Also, the embodiments are described with reference to the related experiments. However, the compounds, materials and steps for providing hydrogen illustrated in the embodiments are not intended to limit the invention. The modifications and variations can be made without departing from the spirit of the disclosure to meet the requirements of the practical applications.
In the embodiments, the hydrogen releasing reaction is turned “on and off” via “contact and non-contact” between the reactants. Hydrogen is generated by adjusting a contact area between the reactants. The larger the contact area, the faster the hydrogen releasing rate. When the reactants are in a contact condition, the hydride powder reacts with water (from a water-containing reactant) to bring about the hydrogen-releasing reaction, and the catalyst powder catalyzes the hydrogen-releasing reaction. When the reactants are in a non-contact condition, the hydrogen-releasing reaction is terminated and hydrogen generation stops.
The reactants include at least a hydride powder, a catalyst powder and a water-containing reactant. Any two of the hydride powder, the catalyst powder and the water-containing reactant could be selected to contact or be non-contact with the remaining one of the reactants. The hydride powder and the catalyst powder could be referred as the solid hydrogen fuel. In an embodiment, any two of the hydride powder, the catalyst powder and the water-containing reactant could form a mixture, and a hydrogen releasing reaction is controlled via contact between the mixture and the remaining reactant for generating hydrogen. In a contact condition, the hydride powder reacts with the water-containing reactant to bring about the hydrogen-releasing reaction, which is catalyzed by the catalyst powder. In an embodiment, a contact area between the mixture and the remaining reactant is substantially proportional to the hydrogen generation rate. For example, when the contact area between the mixture and the remaining reactant is larger than half area of a complete contact area, the hydrogen generation rate is larger than half of theoretical maximum in the design.
In an embodiment, the hydride powder and the catalyst powder could be individually ground and then mixed well as a mixture. Alternatively, the hydride powder and the catalyst powder could be ground and mixed simultaneously. The mixture containing well-mixed hydride powder and catalyst powder are pressed to form a solid block. The “grinding” or “individually grinding followed by mixing” process could be performed by various types of crushers, millers, mills and grinding machines. When the solid block contacts with the water-containing reactant, the hydrogen releasing reaction is activated (i.e. “on”) to generate hydrogen. When a contact area actually between the mixture and the remaining reactant is larger than ½ of a maximum contact area, the hydrogen generation rate is larger than ½ of designed maximum rate. When the solid block and the water-containing reactant are in a non-contact condition, the hydrogen releasing reaction is terminated (i.e. “off”) to stop hydrogen generation. The water-containing reactant could be the water gel, and subjected to pre-treatment before use. For example, before contacting the water gel with the solid block, water is added into a bottle having the water gel.
In an alternative embodiment, the hydride powder and the water-containing reactant could be individually ground and then mixed well as a mixture. The mixture containing well-mixed hydride powder and the water-containing reactant are pressed to form a solid block. Similarly, when the solid block contacts with the catalyst powder, the hydrogen releasing reaction is activated (i.e. “on”) to generate hydrogen. When the solid block and the catalyst powder are in a non-contact condition, the hydrogen releasing reaction is terminated (i.e. “off”) to stop hydrogen generation. Since the price of the catalyst powder is high, the catalyst powder in this method can be recycled and reused. It not only saves the cost, but also protects the environment from wasting the resource. It also facilitates recycling of the catalyst powder.
In an embodiment, the hydride powder could be boron hydride, nitrogen hydride, carbon hydride, metal hydride, nitrogen borohydride, carbon borohydride, nitrogen carbon hydride, metal borohydride, metal nitrogen hydride, metal carbon hydride, metal nitrogen borohydride, metal carbon borohydride, metal nitrogen carbon hydride, nitrogen carbon borohydride, metal nitrogen carbon borohydride, or a combination thereof. Examples of the hydride powder include sodium borohydride (NaBH4), lithium aluminum hydride (LiAlH4), sodium aluminum hydride (NaAlH4), magnesium aluminum hydride (Mg(AlH4)2), calcium aluminum hydride (Ca(AlH4)2), lithium borohydride (LiBH4), potassium borohydride (KBH4), beryllium borohydride (Be(BH4)2), magnesium borohydride (Mg(BH4)2), calcium borohydride (Ca(BH4)2), lithium hydride (LiH), sodium hydride (NaH), magnesium hydride (MgH2), or calcium hydride (CaH2).
In another embodiment, the hydride powder is a hydride or a chemical compound represented by the formula BxNyHz. Examples of compound represented by the formula BxNyHz include ammonia borane (H3BNH3), diborane, H2B(NH3)2BH4, poly(amine-borane), borazine (B3N3H6), borane-tetrahydrofuran complex, and diborane and the likes.
In an embodiment, the catalyst powder may comprise solid acid, or metal salt including at least one of ruthenium, cobalt, nickel, copper and iron, or metal nano-particles/micro-particles including at least one of ruthenium, cobalt, nickel, copper and iron, or a plurality of catalyst metal carriers covered by metal irons/metal atomics/metal nano-particles/meta micro-particles including at least one of ruthenium, cobalt, nickel, copper and iron.
In an application, a flexible polymer matrix may be mixed with the hydride powder and the catalyst powder (i.e. the solid hydrogen fuel) to provide the flexibility and the deformation of the solid hydrogen fuel. The flexible polymer matrix could be a hydrophobic polymer elastomer such as silicone, rubber, and silicon rubber.
In an embodiment, the water-containing reactant could be the liquid state or the solid state. Examples of the water-containing reactant in the liquid state include water, alcohols, alcoholic solutions, aqueous solutions of salts, aqueous solutions of acids, or a combination thereof. The water-containing reactant in the solid state could be a water-absorbing polymer, such as polyacrylate, polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), polyurethane (PU), polyoxyethylene (polyethylene oxide), starch graft copolymer, or rubber blend.
It is noted that the compounds of the hydride powder, the catalyst powder and the water-containing reactant (and the flexible polymer matrix) are not limited to any of aforementioned compounds. Also, the hydride powder, the catalyst powder and the water-containing reactant could be the ground or un-ground powders, dispersed or pressed as the tablets. For example, any two of three reactants are mixed pressed as a tablet, while the remaining reactant is pressed as another tablet. Alternatively, any two of three reactants could be mixed pressed as a tablet, while the remaining reactant is dispersed evenly. It is understood that the states of three reactants could be optionally selected, depending on the requirements of the practical application.
Several experiments are conducted in the embodiment of the present disclosure for observing the effects of “contact and non-contact” between the reactants on the hydrogen generation (i.e. “on and off”). Experiments and the results thereof are disclosed below.
A method for controlling the reaction “on and off” via “contact and non-contact” between the reactants is described below. First, the moveable rod 36 is push downward. When the flexible solid hydrogen fuel 35 contacts the solid water 37 (i.e. the switch is “on”), the hydrogen-releasing reaction is activated and hydrogen is generated, as shown in
1 g of NaBH4 (the hydride powder), 0.3 g of cobalt ion catalyst (Co2+/IR-120, the catalyst powder) and 0.8 g of silicone rubber (i.e. molding agent) are used in an experiment. The experimental results are described below. When the moveable rod 36 is push downward to contact the solid hydrogen fuel 35 with the solid water 37, the switch is “on”. In the “on” state, the hydrogen flow rate is increased to about 13 sccm (standard cubic centimeters per minute) after 2000 seconds. Afterwards, the moveable rod 36 is pulled upward to turn the switch “off”, and the hydrogen flow rate is decreased to about 6 sccm after 1000˜1200 seconds. Since a small amount of water residue resting on the surface of the solid hydrogen fuel 35 would still cause the hydrogen-releasing reaction, the actual hydrogen flow rate would be decreased to about 1-2 sccm. Thus, the switch could be regarded as the “complete off” state although 6 sccm of the hydrogen flow rate is measured.
Another experiment is further conducted for observing whether a repeatability condition of “on and off” is developed.
According to the experiment results, it is indicated that the hydrogen releasing reaction can be effectively turned “on and off” via conditions of “contact and non-contact” between the reactants. Also, when the “contact and non-contact” steps are repeatedly performed, the “on and off” of the hydrogen releasing reaction can still be achieved.
The hydrogen-releasing reaction is not only terminated via the “non-contact” condition. An inhibitor or an inhibiting method, alternatively, could be adopted for suppressing or terminating the hydrogen-releasing reaction, and a hydrogen-releasing rate of the hydrogen-releasing reaction could be controlled and adjusted by the concentration of the inhibitor. In an embodiment, three reactants, including the hydride powder, the catalyst powder (solid hydrogen fuel) and the water-containing reactant, are mixed and shaped into an integrated form, an inhibitor or an inhibiting method might be injected for suppressing or terminating the hydrogen-releasing reaction, and a hydrogen-releasing rate of the hydrogen-releasing reaction is controlled and adjusted by an extent of suppression.
In an embodiment, the inhibitor could be an alkaline liquid, Isopropyl alcohol (IPA), the material able to react with water and forming an oxide, the material strongly absorbing or removing water, or the material able to isolate the hydride powder from water.
Examples of the inhibitor materials able to react with water and forming an oxide include, but not limited to, iron powder, aluminum powder, magnesium powder, calcium powder, calcium hydroxide, calcium oxide, and nano-particles thereof.
Also, the inhibitor could be sulfuric acid or sodium acetate, capable of strongly absorbing or removing water.
Also, the inhibitor could be a surfactant able to isolate water from the hydride powder and the catalyst powder.
Besides the inhibitor, an inhibiting method could be adopted for suppressing or terminating the hydrogen-releasing reaction. The inhibiting method could be any method capable of removing water, such as a heating method. In an embodiment, the heating method is performed by a high heating temperature furnace for removing water, and the heating temperature is in a rage of about 40° C.˜400° C., depending on the practical application. Moreover, the heating method could be conducted by using the heat released from an exothermic reaction of the inhibitor and water, and examples of the inhibitor include iron powder, aluminum powder, magnesium powder, calcium powder, calcium hydroxide, calcium oxide, and nano-particles thereof.
An experiment is conducted by using calcium oxide as the inhibitor for suppressing or terminating the hydrogen-releasing reaction. The procedures and experimental results are described below.
According to the aforementioned disclosure, the one-off and adjustment method of hydrogen releasing from chemical hydride is performed by the “contact and non-contact” procedures for switching the reaction “on and off” effectively. Hydrogen is generated by adjusting a contact area between the reactants. The contact area is positively proportional to the hydrogen releasing rate. When a contact area actually between the mixture and the remaining reactant is larger than ½ of a maximum contact area, the hydrogen generation rate is larger than ½ of designed maximum rate. Alternatively, an inhibitor or an inhibiting method could be adopted for suppressing or terminating the hydrogen-releasing reaction, and a hydrogen-releasing rate of the hydrogen-releasing reaction could be controlled and adjusted by the extent of the suppression. According to the embodiment, the hydrogen releasing reaction and hydrogen generation rate are effectively controlled by an easy and simple method. Without the complicate and bulky mechanism, the small volume of the disclosed system is easier for the user to carry, and the production cost is greatly decreased. the methods of the embodiment have several advantages. Also, it is easier to match the mechanical design of the system and product, which simplifies the design of hydrogen production system. Furthermore, solid hydrogen fuel releases hydrogen completely, more effectively and rapidly. Above advantages increase users' willingness to use the product and widen the application field of the product.
While the disclosure has been described by way of example and in terms of the exemplary embodiment(s), it is to be understood that the disclosure is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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099122243 | Jul 2010 | TW | national |
201010243281.5 | Aug 2010 | CN | national |
This application claims the benefits of U.S. provisional application No. 61/285,467, filed Dec. 10, 2009, Taiwan application Serial No. 099122243, filed Jul. 6, 2010 and People's Republic of China application Serial No. 201010243281.5, filed Aug. 3, 2010, the subject matters of which are incorporated herein by reference.
Number | Date | Country | |
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61285467 | Dec 2009 | US |