WO2009086541A1 - Hydrogen production system using dosed chemical hydrbdes - Google Patents

Abstract

A hydrogen storage and generation system of the present invention includes containers for a fuel reactant, liquid reactant, and reaction product. A control system of the present invention generates hydrogen gas. Hydrogen storage and generation system use non-water based reactions of chemical hydrides. Apparatus of the present invention allows for production of predetermined hydrogen amounts with a greater control of the generation rate and higher yields than the devices that use the hydrolysis of chemical hydrides by providing solid hydrides in dry form or suspension, sealed against premature reaction and dispensed to a reactor through a control system.

Description

HYDROGEN PRODUCTION SYSTEM USING DOSED CHEMICAL HYDRTOES

RELATED APPLICATION

[0001] This application that claims the benefit of and priority to a provisional application serial number 61/009,267 filed on December 27, 2007 in the United States and incorporated herewith by reference in its entirety.

FIELD OF THE INVENTION [0002] The present invention generally relates to an apparatus that stores hydrogen by chemical means and generates the gas only when needed in an industrial process, or an electrochemical or chemical reaction.

DESCRIPTION OF THE RELATED ART [0003] Hydrogen fuel cells are electrochemical devices that convert chemical energy stored in hydrogen and oxygen into water, electrical energy, and 1 hernial energy. Elemental oxygen (O_?) is an abundant component present within air and thus can be easily conveyed to a hydrogen fuel cell. Conversely, elemental hydrogen (H₂) is not readily available in nature. Consequently, hydrogen must be stored within devices that employ the hydrogen fuel cell. Electrical energy production of such devices is directly dependent on the amount of hydrogen stored in the device and efficiency of the overall system.

[0004] Storage of large quantities of hydrogen in small volumes and with minimal mass is very important for the commercialization of devices employing hydrogen fuel cells. In practice, hydrogen storage is complicated due to the low volumetric energy density of hydrogen gas. For example, to store large amounts of chemical energy in the form of hydrogen gas necessitates a large volume. Further, even under pressure (to condense the hydrogen gas) liquid hydrogen has almost five (5) times less volumetric energy density than conventional liquid gasoline. In order to reduce volume requirements of the hydrogen, chemical hydrogen storage methods have been developed and employed. Examples of such chemical storage methods include the use of compounds having "bound-up" hydrogen atoms, such as metal hydrides, hydrocarbons, and chemical hydrides. Such compounds can be reacted to release hydrogen gas. A common reaction scheme employed is a hydrolysis reaction between a metal or chemical hydride and water to form hydrogen. [0005] To store large amounts of energy in the form of hydrogen usually requires devices that are heavy and possess large volumes. One of the approaches to reduce the hydrogen storage weight and volume is the use of various chemicals rich in hydrogen. Examples of these are metal hydrides, hydrocarbons, and chemical hydrides. Chemical hydrides are the compounds of negatively charged hydrogen ions and other elements. Sodium borohydride is one of the examples with the chemical formula NaBH₄ It is a white solid, usually encountered as a powder or confectioned into granules and pellets. Sodium borohydride melts at 400⁰C, and thermally decomposes at temperature higher than 400⁰C. It is soluble in water and methanol; however, it reacts with both unless a strong base is added to suppress solvalysis. [0006] Chemical hydrides such as sodium borohydride have the potential to be used in hydrogen storage devices since they have very high volumetric and gravimetric hydrogen densities. For example, 1 gram of sodium borohydride diluted in 4 grams of water has approximately 5mL volume, and produces 0.21 grams of hydrogen (2.6L at room temperature and pressure). To store the same amount of hydrogen in the same volume at 25°C would require compression to 1,287 atmospheres (~18,914psig or -130,40IkPa). Of the readily available chemical hydrides, sodium borohydride has the highest specific hydrogen yield with the lowest specific energy release. These characteristics coupled with its chemical and thermal stability have made it an especially attractive hydrogen storage option for fuel cell devices. The usefulness of sodium borohydride to generate hydrogen whenever the use of the compressed gas was inconvenient was first mentioned by Schlesinger et al. Typically, hydrogen is released from sodium borohydride via the hydrolysis reaction, as shown in [0007] NaBH₄ (s) + 4H₂O(I) → NaB(OH)₄ (s) + 4H₂ (g) + heat .

[0008J As exothermic, the hydrolysis occurs spontaneously at any temperature. In addition to hydrogen and heat, NaB(OH)₄ (sodium metaborate) is formed as a second reaction product.. The practical hydrogen generator systems that employ sodium borohydride are typically flow-reactors that require both sodium borohydride and metaborate to be completely dissolved in water.

[0009] In most applications, this requirement drastically decreases the theoretical hydrogen production ratio of these systems because excess water is needed to dissolve sodium metaborate. Note that the solubility limit of sodium metaborate is 5.2% wt, as compared to 35.5%wt for sodium borohydride. To keep sodium metaborate in solution, the reaction mixture must be diluted at least to its solubility limit. This dilution results in a maximum hydrogen production ratio of only 0.4% wt. Due to this low hydrogen content weight percent, many sodium borohydride hydrogen generation systems require the use of water reclamation systems included in a storage device. In several prior art applications, solvents were tested and it was uncovered that solvents can dissolve more efficiently sodium metaborate, a product of the sodium borohydride and water reaction. It was found that by adding ethylene glycol, the concentration of sodium borohydride solution in water can be increased by 50%, namely from 10%wt. to 15%wt, resulting in increased hydrogen storage capacity. The presence of ethylene glycol is useful not only for its ability to dissolve sodium metaborate, but it also improves the fuel cell tolerance to extreme temperatures: it reduces the freezing temperature and increases the boiling temperature of water. The rate of sodium borohydride hydrolysis dependents on pH and temperature as given in empirically derived ^lθ^ ',/: M = P* - (0.0347M - 1.92) where t_{i 2} is the half life of the reaction and T is the solution temperature. Since directly proportional to the reaction half life, the reaction rate vary with pH and temperature.

[0010] Typically strong bases such as 30 % wt sodium hydroxide are added to a sodium borohydride water solution to increase pH to minimum 13. Even though the hydrolysis is hindered by this high pH, it still proceeds, and the solution is practically stable only for couple of days. The evolved hydrogen imposes safety issues onto the hydrogen generator limiting its application only to continuous operations to avoid the hydrogen build up in the dissolved sodium borohydride container. One of the approaches to overcome this disadvantage of the current hydrogen storage and generation technology is disclosed in United States patent Publication No. 2004/0047801 . Solid sodium borohydride is stored on board of the hydrogen generator device and dissolved in water when hydrogen is needed. [0011] However, even in the design disclosed in the United States patent

Publication No. 2004/0047801. the uncontrolled hydrogen release may occur in the reaction of the unprotected chemical hydride with water vapor absorbed from the surrounding environment. The reaction of water and sodium borohydride is rather slow at low temperatures including room temperature. Acids, buffers, solid catalysts, or heat are commonly used to increase the reaction rate. Thus, the catalytic control of sodium borohydride hydrolysis has been of interest nearly since its discovery.

[0012] Another prior art method provided a comprehensive discussion of catalytic and acidic methods to improve sodium borohydride - water reaction rates. More recent studies have identified solid catalysts. Still another prior art method identified metal oxide supported metals such as Pt-TiO₂, Pt-CoO, and Pt-LiCoO₂ as having catalytic properties that promote the sodium borohydride - water reaction. In addition, as disclosed in United States Patent 6,683,025, the preparation method of a metal catalyst used for a commercial sodium borohydride-water reactor is described as well. All the catalysts studied and described throughout the scientific and patent literature are usually in a solid phase. [0013] However, solid catalysts suffer from certain limitations. For example, the effectiveness of solid catalysts depends highly on its probable contact with the reactants. Therefore, catalyst surface area is a key factor that affects the rate of reaction. Solid catalysts are also susceptible to fouling due to impurities or reaction products. This is especially the case with the sodium borohydride - water reaction, where one of the products, sodium metaborate, is less soluble in water than the reactant. Conditions for the localized deposition of sodium metaborate at the catalyst active sites are created by its lower solubility. The addition of excess water is typically used to resolve this problem; however, it results in a lower hydrogen storage capacity of the sodium borohydride-water reaction system. [0014] Other disadvantages of a solid catalyst are cost, degradation with time, and occasionally, the limitations of reaction temperature and pressure caused by the catalyst physical fragility. In addition to water, sodium borohydride reacts with hydroxy! groups in other compounds such as alcohols. It has been shown that in alcohols, sodium borohydride undergoes alcoholysis, a chemical reaction similar to hydrolysis. In this reaction hydrogen and sodium borate complexes (alcoholates, or alkoxides) are common reaction products. It has been demonstrated that sodium borohydride and various organic and inorganic acids react very vigorously generating hydrogen and heat. Acetic acid reaction with sodium borohydride is one of the well studied examples. The extensive review of the reaction chemistry of this read ion was given by Gribble. He showed that the molar ratio of the reactants determined whether more reactive (mono) acyloxyborohydride or less reactive triacyloxyborohydride were formed in addition to hydrogen To evaluate reactivity of sodium borohydride dissolved in water with various species, oxygenated hydrocarbon, potassium hydroxide, iron oxide and metal chlorides were used.

[0015] The results showed that sodium borohydride reacted exothermally with oxygenated carbohydrates releasing hydrogen. Oxygenated hydrocarbons are internal combustion fuels that typically are the mixtures of primary alcohols, ketones, ethers, silicon based emulsifiers, and surfactants. With other oxygen containing organic groups such as aldehydes and ketones, sodium borohydride reacts as well. The reduction reaction activity of sodium borohydride and these oxygen containing groups is described by Abdel-Akher et al. For their study, Abdel-Akher reacted various sugars with sodium borohydride in aqueous solution. It was shown that the rate of reduction was fairly rapid and dependant upon the amount of sodium borohydride used.

[0016] In view of the foregoing, there remains an opportunity to provide new system and methods of producing hydrogen that do not require the use of excess water and/or solid catalysts.

SUMMARY OF THE INVENTION AND ADVANTAGES [0017] The subject invention provides apparatus and methods for forming hydrogen gas. The method comprises the steps of providing a reactor and providing a hydrogen-generating composition to the reactor. The hydrogen-generating composition employed in preferred embodiments consists essentially of a borohydride component and a glycerol component. The borohydride and glycerol components are preferably present in a generally three to four stoichiometric ratio, prior to reaction. The borohydride component has hydrogen atoms and the glycerol component has hydroxyl groups with hydrogen atoms. The method can further comprise the step of reacting the borohydride component with the glycerol component, thereby converting substantially all of the hydrogen atoms present in the borohydride component and substantially all of the hydrogen atoms present in the hydroxyl groups of the glycerol component to form the hydrogen gas.

Reactors and reaction systems employing the methods according to aspects of the present invention are also provided. A hydrogen production system can form a hydrogen gas composition through a new chemical reaction of chemical hydrides and a liquid reactant to be widely used in such application. A first container of the system stores a hydride component. A second container stores a glycerol component. A reactor device is cooperable with the first chamber and the second chamber; a dispenser cooperable with the first container and the second container and the reactor device for selectively dispensing the hydride component and the glycerol component to the reactor device; and the reactor device cooperable with the container and the dispenser for reacting the hydride component with the glycerol component thereby converting substantially all of hydrogen atoms present in the hydride component and substantially all of hydrogen atoms present in the glycerol component to form the hydrogen gas composition device of the present invention is designed to store and generate hydrogen using the reaction of a chemical hydride, and liquid reactant. In a preferred embodiment, liquid reactant may be glycerol or a glycerol containing mixture.

A chemical hydride and liquid glycerol reactant can be stored in separate containers and combined into a reaction chamber when hydrogen is needed. Moreover, solid chemical hydride can packed in the organized manner to be protected from exposure to environment. The chemical reaction of chemical hydride and glycerol generates a liquid compound as reactant product in addition to hydrogen. The design of the present apparatus may support batch type reaction if both reactants are combined in a reaction chamber in the stoichiometric ratio. The liquid reactant product can then be removed from the chamber after each reaction.

In addition, the invention can also provide a design that supports semi-batch reaction type when only a chemical hydride is added in stoichiometric quantity into entire amount of the liquid reactant. In this device design, a liquid reactant container serves as a reaction chamber, and a waste container as well. Hydrogen generated can transferred passively into a fuel cell or the like. The excess of hydrogen is temporarily stored in a low pressure container. When hydrogen consumption is completed, any hydrogen left can be purged out from the system. [0018] An advantage of the present invention is to provide an improved design of a system for storing and generating hydrogen that is compact and has a wide application range for the hydrogen consuming devices that may convert hydrogen at very small to very high rates. [0019] Another advantage of the present invention is to provide a device capable of accommodating a wide range of hydrogen amounts stored and wide variety of hydrogen production rates without modifying the assembly. [0020] Still another advantage of this invention is that the hydrogen release rate is scalable, meaning that the rate of hydrogen generated can be controlled by using means other than catalysts such as, but not limited to, by changing reactant concentrations, adding or subtracting heat from the reaction chamber, mixing or agitating the reactants during the reaction, and/or by changing the diffusion characteristics of the reactants through changes in reactant temperature and/or pressure, reactant viscosity, and by adding surfactants. [0021] Still another advantage of the present invention is that a catalyst is not required for hydrogen evolution, thus excluding potential problems that impede the current hydrogen storage and production technology based on chemical hydride - water chemistry. However, if necessary, the new hydrogen release chemistry may be combined with a solid or liquid catalyst to accelerate the hydrogen release. [0022] Still another advantage of this reaction is that the reaction temperature may be controlled internally. Specifically, reaction temperature may be varied by various active or passive additives included into the reaction. Reaction acceleration is possible to achieve with a small amount of an active additive added to react with a chemical hydride very fast and to instantaneously generate heat high enough to activate the rate determining step in the reaction of the chemical hydride and glycerol. Since it is exothermic, this reaction is self sustained and will proceed at the desired rate. On the other hand, to slow down the reaction rate, an inert compound may be added into the reaction chamber along with the reactants to absorb the excess heat and thus cool the reaction mixture.

[0023] Still another advantage of the present invention is the increased safety and shelf life of the hydrogen storage due to storing the reactants in separate containers. In particular, the chemical hydride and liquid reactant are placed in two separate containers made of chemically compatible materials that protect the chemical hydride and liquid reactant from undesirable reactions. In this way, hydrogen is formed only when the reactants are combined in the reaction chamber as hydrogen is needed. Moreover, the containers are placed into separate cartridges that provide additional protection to the chemicals. [0024] Still another advantage of this invention is to provide increased safety and shelf life due to the way the chemical hydride is stored. Specifically, the predetermined unit dosages of a dry solid chemical hydride that may include powder, granules, or pellets, are packaged using a strip or blister packaging method. The continuous strip packages are made from chemically resistant and impermeable foils that are sealed to protect the solid chemical hydride from the uncontrolled reaction with compounds potentially present in environment such as water or water vapor or any other chemical that may react with chemical hydride. The size of the chemical hydride packages may be scaled up or down, depending on the amount of hydrogen required to be generated at the time. [0025] Still another advantage of this invention is that the reactant cartridges can be replaced easily on site without down time in the device operation. In particular, when the reactants are consumed, empty cartridges can be removed and sent back for recycling, while the new ones are installed without the interruption of the device operation. [0026] Still another advantage of this invention is that different types of cartridges may be used to accommodate the strip packaged solid chemical hydride. In particular, the designs may have different shapes and dimensions that allow for the most compact strip packaging. In addition, the release and/or dispensing mechanism may also be included in the cartridges. [0027] Still another advantage is that hydrogen is not present in the system unless required by fuel cell. In particular, the excess of generated hydrogen is only temporarily stored in a low pressure collapsible container while the fuel cell operates. Once the fuel cell is turned off, the unconsumed hydrogen is purged out from the system. [0028] Still another advantage of this invention is to provide a system that has an inexpensive, and low weight and volume balance of plant that increase the total hydrogen energy density and decreases the device cost. In particular, a low operating pressure and temperature allow for using components made of advanced engineering materials based on polymers that are light weight, durable and inexpensive. [0029] Still another advantage of the present invention is to provide an improved device that can work within a wide range of ambient temperatures. In particular, the presence of glycerol reduces problems related to subzero operation. As it is freeze tolerant, glycerol is a liquid that flows even at temperatures below 0⁰C. [0030] Still another advantage of this invention is to provide the usage of low power electronics to control the system operation. The power electronics may be directly powered by a fuel cell, battery, solar cell, or grid. Microcontrollers, sensors, and switches are the components used to regulate safe and independent system operation. In addition, a wireless data transmission and GPS can be included to control strategy as well to monitor and control the system operation remotely and to track the system location.

BRIEF DESCRIPTION OF THE DRAWINGS [0031] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: [0032] Figure 1 illustrates a schematic view of a representative hydrogen storage and generation system with a batch reactor that produces hydrogen from a chemical hydride and liquid reactant; [0033] Figure 2 illustrates a schematic view of an alternative embodiment of a hydrogen storage and generation system with a semi-batch reactor of the present invention;

[0034] Figure 3 illustrates a schematic view of still another alternative embodiment of a hydrogen storage and generation system; [0035] Figure 4 illustrates a side view of a reaction chamber with a gate valve, fluid lines, a pumping system, and a pellet dispensing mechanism;

[0036] Figure 5 illustrates a side view of a dispensing mechanism for strip packaged sodium borohydride pellets; [0037] Figure 6 illustrates a side view of a spool with a strip of pellets and the dispensing mechanism of Figure 5;

[0038] Figure 7 illustrates a side view of an exemplary spool and associated lock nut and washers disassembled;

[0039] Figure 8 illustrates an exemplary chemical hydride cartridge; [0040] Figure 9 illustrates a series of collapsible containers for liquid rcactant;

[0041] Figure 10 illustrates a cross sectional view of one of the containers as shown in Figure 9;

[0042] Figure 1 1 is a chart of the relative performance of an open cathode fuel cell using bottled hydrogen compared to hydrogen produced in a hydrogen storage system according to aspects of the present invention;

[0043] Figure 12 is diagram of an exemplary control system for the operation of a hydrogen generator according to aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0044] The present invention provides various apparatus and methods for forming hydrogen (H₂) gas. Hydrogen gas formed from the method of the present invention can be used for various purposes. The invention encompasses a hydrogen storage and generation system (the system), generally shown at 10 in Figure 1 . The system 10 can be utilized for a new chemical process for hydrogen production. The hydrogen production process used by the system 10 can be based on the alcoholysis reaction of chemical hydrides and glycerol. The system 10 in its preferred embodiment utilizes chemical hydrides. The chemical hydrides are the compounds of negatively charged hydrogen ions and other elements. Sodium borohydride is one of the examples with the chemical formula NaBH₄ used. It is a white solid, usually encountered as a powder or confectioned into granules and pellets. Sodium borohydride melts at 400⁰C, and thermally decomposes at temperature higher than 400⁰C. It is soluble in water and methanol; however, it reacts with both unless a strong base is added to suppress solvalysis. Glycerol, a liquid reactant used in this invention, known also as glycerin, or 1 ,2,3-propanetriol, is a trihydroxyl alcohol with molecular formula CiH₈(OH)_S. It is a colorless, odorless, sweet-tasting, syrupy liquid that melts at 17.8°C, and boils with decomposition at 290⁰C. It is miscible with water and other polar solvents. Glycerol is present in the form of esters (glycerides) in all animal and vegetable fats and oils. It is obtained commercially as a byproduct of their hydrolysis. It is also synthesized on a commercial scale from propylene produced by petroleum cracking. According to an aspect of the invention, the spontaneous reaction of glycerol and sodium borohydride produces hydrogen and heat in addition to a sodium borate complex. The amount of hydrogen gas released during the reaction between sodium borohydride and glycerol may be presented with the following general equation: [0045] nNaBH, + 4R(COH)_n → {NaB)n(RC_nO_n )₄ + AnH₂ t

[0046] where in is 3, and R is H₅ for glycerol. It is important to note that all hydrogen atoms present in sodium borohydride and glycerol hydroxyl groups are converted into hydrogen gas. [0047] Chemical conversion in this reaction is localized at the phase interface.

The boundary layer formed at the solid surface of sodium borohydride consists of a saturated solution of reaction products. One of the limiting factors for the reaction is the diffusion rate of glycerol to the sodium borohydride surface and the diffusion of the reaction product away from the sodium borohydride surface. A method used to control the diffusion of glycerol and the reaction product is the change of viscosity. One of the ways to change viscosity is temperature. For example, the increase of temperature from 2O⁰C to 40⁰C causes glycerol viscosity to drop by almost a factor of 5 (from 14.10 Poise to 2.84 Poise). Alternatively, the viscosity of glycerol can be changed by dilution. Examples of diluents that can be used in the invention are water and alcohol. For example, 80%wt aqueous glycerol solution has a viscosity of 0.60 Poise at 20⁰C that is a drop in viscosity by a factor of 24 in comparison to pure glycerol at the same temperature. The diffusion limitations of this reaction can also be overcome through mixing, stirring, or physical manipulation of the reaction mixture such that convective mass transport becomes the dominating flow effect. Mixing can be achieved not only through external means but also taking advantage of temperature increase to promote natural convection.

[0048] Ways of controlling the reaction rate of glycerol and sodium borohydride at ambient temperature can include the use of different additives that change the reaction temperature. One method includes the addition of a pure or diluted acid. Typically, the reaction of sodium borohydride and an acid is highly exothermic. Heat generated during such a reaction can then be used to trigger the reaction of glycerol and sodium borohydride. Examples are the reactions of sodium borohydride and glycerol in the presence of concentrated or diluted acetic acid. A small amount of the acid added into glycerol reacts instantly with sodium borohydride. The heat released into the reaction mixture is high enough to activate the reaction of sodium borohydride and glycerol. Since this reaction is exothermic, the heat released in this reaction increases the temperature of the reaction mixture. The temperature can be kept uniform during hydrogen generation by the addition of a certain mass of a non-reactant. For example, predetermined volumes of reaction waste that depend on ambient temperature can be added into the reaction chamber along with the reactants to evenly distribute and maintain temperature in the reactor during hydrogen generation. [0049] The reaction rate of the exemplary sodium borohydride and glycerol can be changed with the addition of solid catalysts. One exemplary catalyst is activated carbon—an inexpensive, bio-derived, and bio-degradable catalyst. Activated carbon is known as a catalyst that promotes hydrogen transfer reactions. Activated carbon can facilitate heterogeneous catalysis of the sodium borohydride - glycerol reaction. It can be used in a form of finely dispersed powder, pellets, or particles suspended in glycerol. Low catalyst cost and preparation from renewable sources allow discarding it along with the reaction product or recycling it by filtration, washing and drying. [0050] An apparatus of the present invention is generally shown in Figure 1 illustrating one of the embodiments. The apparatus is designed to produce hydrogen from a solid chemical hydride and liquid reactant, such as glycerol. In a preferred embodiment shown in Figure 1, the reaction is performed in a batch type reactor where stoichiometric quantities of both reactants can be combined as required. The device includes a chemical hydride container 14, a chemical hydride dispenser 16, a liquid reactant container 18, a pump for dispensing liquid reactant 20, a reaction chamber 22, a reaction waste container 24, a pump for removing waste from the reaction chamber 26, a pump for placing the waste back into the chamber 28, a liquid- gas separator 30, and a hydrogen overflow container 32 that supplies the gas to a hydrogen consuming device, such a fuel cell 34 or the like. In another embodiment presented in Figure 2, a lay out of a hydrogen system with a semi-batch reactor is generally shown at 100. The simplified device is comprised of a chemical hydride container 1 10, a chemical hydride dispenser 1 12, a liquid reactant container 114, a liquid-gas separator 1 16, and a hydrogen overflow container 1 18. [0051] The hydrogen storage and generation system design, as shown at 100 in Figure 2, has fewer components and a simplified operation compared to the system 10 shown in Figure 1. The liquid glycerol reactant container 1 14 as shown in Figure 2 can be a reactant chamber and waste container at the same time. Because the liquid reactant container 114 is a reaction chamber and waste container at the same time, the liquid reactant pump 20, the reaction chamber 22 and the waste pumps 26 and 28 of the Figure 1 system 10 can be eliminated in this design. The solid reactam. can be directly dispensed into a liquid container 1 14 where the hydrogen is generated. The waste produced during the reaction stays in the liquid reactant container 1 14. The only fluid line in this design can be a hydrogen line that transfers the gas flow from the liquid reactant container 114 to the hydrogen container 1 18 and then to the fuel cell 34.

[0052] In a further alternative system 200 shown in Figure 3, the device can include a chemical hydride container 210, a chemical hydride dispenser 212, a liquid reactant container 214, a pump for dispensing liquid reactant 216, a reaction chamber 4, a reaction waste container 224, a pump for removing waste from the reaction chamber 222, a pump for placing the waste back into the chamber 220, a liquid-gas separator 216, and a hydrogen overflow container 218 that supplies the gas to a hydrogen consuming device, such the fuel cell 34 or the like. In this embodiment, the hydrogen gas produced in the reaction chamber 4 can be routed through the reaction waste in container 224 for cooling and dehumidification before routing to the separator 216, and storage container 218.

[0053] In the various systems, the powder, granules, or pellets of a dry solid chemical hydride (or a chemically inert suspension) can be protected from uncontrolled reactions with any chemical compounds present in environment including water vapor or liquid water. The individual dosages of dry or suspended solid chemical hydride can be packaged in heat sealed, impermeable and chemically resistant materials. The packages may be further organized in different ways, depending on the system application. For instance, the chemical hydride packages may be connected in continuous strips, or heat sealed punch cards. The amount of the total chemical hydride or individual packages may be scaled up or down, depending on the hydrogen required to be stored, or generated at a given time. [0054] As an example, sodium borohydride pellets can be used as a solid chemical hydride for hydrogen production. One gram pellets are strip packaged. AS shown in Figure 5, each pellet 121 is wrapped in a pocket 122 of that is a part of a continuous strip 312. The pellets may be enclosed between two laminated webs forming the strip 312 either made of the same or different materials that offer a high degree of protection from environment. The webs can be heat sealed along edges and between each pellet. A strip may also consist only of one web wrapped around pellets and heat sealed only along one side. Similarly, the pellets may also be organized by blister packaging. The procedure of pallet packaging is similar to the strip packaging with the only difference that the bottom laminate is preformed by either thermoforming or cold forming, and then the lid material is sealed to the one on the bottom keeping the individual pellets in the shaped pockets.

[0055] The chemical hydride packages are stored in a container that is connected to the rest of the system by various means to provide chemical hydride when hydrogen is demanded. Chemically compatible materials are typically used for the container fabrication. The container may have any shape and size adjusted to the amount of chemical hydride stored, to minimize the total volume and weight occupied by the chemical hydride in the device of the present invention. The chemical hydride may be packaged within a container by different ways that are optimized for the particular applications. As an increased redundancy of the whole device, the chemical hydride container may be placed into a cartridge that provides additional protection and eases the reload of the exhausted chemical hydride strips. In addition, a mechanism for hydride release and dispensing may also be included in the same cartridge.

[0056] For example, the chemical hydride container 14 and the pellet dispenser 16 can be packed together in a chemical hydride cartridge, generally shown at 300 in Figure 8. The strip packaged pellets 312 may be fabricated and then packed in a zigzag formation as shown in Figure 8 and may be kept in order with an adjustable plate 326, which might be spring loaded. The volume of the container 14 is adjustable to the strip packaged pellet volume and decreases over time with the pellet consumption. The strip packaged pellets 312 exit the container 14 through an outlet 328 in the plate 326. The strip 312 is pulled out from the container 14 by a take up spool 334. The rod 329 leads the strip 312 to the dispensing roller 331 and aligns the strip 312 between the outlet 328 and the take up spool 334. When a pellet is positioned over the dispensing roller 331 it may be released from the pocket 123 by slicing the outward laminate, such as with a spring loaded knife or other cutting or perforating device (not shown). A released pellet from the cartridge 300 can then fall into a dispensing funnel 343 through a gate valve 344 opening and enter the reaction chamber 346, as shown in the embodiment of Figure 4. The strip package laminate material left after the pellet release is wound on the take up spool 334. Two round plates 335 keep the waste strip package material orderly wound around the shaft 333 of the take up spool 334. A brushless DC motor 337 interlocks a shaft 333 and creates a tensional force on the strip 312 between the take up the spool 334 and the outlet 328. [0057] In another embodiment shown in Figures 5, 6 and 7, a spool 311 is utilized as the pellet container. Two round sides 313 of the spool hold the strip package pellets 312, wound around a shaft 315. The shaft 315 consists of a metal rod 317 with threaded holes 319 on each end that is inserted into a plastic tube 318. The metal rod 317 is locked in the spool mounting brackets 323 with lock nuts 320. Washers 321 and 322 can be placed on each face of a bracket to facilitate tension on the strip package 312 during rotation.

[0058] The take up spool 334 pulls the strip 312 out from the spool 31 1 to the dispenser 16. As an option in this embodiment, a spool 329 with two guiding pins 292 that lead the strip 312 to a dispensing roller 331 and align it between the outlet 328 and the take up spool 334 may be included. [0059] The chemical hydride packages are opened and the hydride is dispensed into the hopper 343 or other conduit to the reaction chamber 346 when hydrogen is needed. Two steps may occur simultaneously or consecutively depending on the rate at which the chamber is opened. For example, for fast opening chambers, the two processes proceed simultaneously; however, a slower process requires the consecutive steps. The package opening mechanisms may include any design that provides a method to release the chemical hydride from an individual package. The opening methods may include but are not limited to cutting, slicing, delamination, or punching through. Once released, a solid chemical hydride is directed to enter into the reaction chamber 346. The process may be passive and driven only by gravitation; however, it is not limited to it, and may occur by ways that are gravity independent as well.

[0060] When the device of the present invention is in operation, the reaction chamber is tightly closed. It may open only to accept the chemical hydride. The various mechanisms may be employed to switch on and off the chamber 346 opening, and to set intermittent or continuous flow of the chemical hydride into it. They may include but are not limited to various valves such as plug, ball, butterfly, or gate, or different mechanism specifically designed for this application. The process of the hydride release and the chamber opening are synchronized by the system controls to minimize the time the chamber is open. The chemical hydride package opening and dispensing are explained in the following examples given for the sodium borohydride strip packaged pellets.

[0061] In addition to the described pellet release mechanism by cutting the laminate, the packages can also be open by splitting the strip top and bottom laminates. In this embodiment an additional take up spool (not shown) is positioned in line with the spool 334 and symmetrically to the spool 331. Each spool winds one laminate layer and thus separate the strip package with a pellet by tension. [0062] In general, the strip packaged pellets 312 are stored in a chemical hydride container. The strip with pellets 312 can be packed in a zigzag formation or wound on a spool. A solid chemical hydride dispenser 16 and 1 12 releases each pellet from the strip package 312 and dispenses it into a reaction chamber. Chemical hydride container and dispenser are made of materials that are chemically, thermally and mechanically resistant at the operating conditions. Typically, the materials used for the manufacturing of the containers and dispensers may include plastics, plastic composites, and metals and metal alloys.

[0063] The operation of the dispenser 16 may be controlled by microcontrollers, and sensors. The dispenser 16 is activated by electrical pulse transmitted from a controller to a dispenser solenoid valve or the motor 327. The liquid reactant container 18 stores a reactant, such as a glycerol based liquid reactant used for hydrogen generation. The liquid reactant is dispensed from the container 18 into the reaction chamber 22 in a stoichiometric quantity. Pumps such as diaphragm, peristaltic, or elastomeric may be used to dispense the exact volume of the liquid glycerol reactant. [0064] In addition, it can also be dispensed by other means including valves with flow meters, and switches, or sensors that shut the liquid flow when necessary. The liquid container 18 may be collapsible or non collapsible and made of a plastic based impermeable material resistant to the operational pressure, temperature and chemicals used in the system. When the liquid reactant is completely used up, the collapsible container 114 loses volume and occupies very little space in the system. The dispensing of the liquid reactant is activated in the same way as of the solid reactant. As it is freeze tolerant, the glycerol based liquid reactant can flow within a wide temperature range, thus expanding the system operation to subzero temperatures. [0065] In some embodiments, the liquid reactant container 18 and 1 14 can be packaged along with the waste in the same cartridge. The waste may be stored in a separate container similar to the liquid reactant. However, the liquid reactant can be stored in a collapsible container and the waste placed within non collapsible waste container. The volume and packaging of this embodiment provides minimized volume and weight of the liquid components. The liquid glycerol reactant and solid chemical hydride are dispensed and combined in the reaction chamber 22, 346 to produce hydrogen. The chamber 346 can be open and closed by various means that are the part of the system's dispensing mechanism. As an example, the gate valve 344 illustrates the basic principles of the chamber 346 design. In this embodiment, the chamber 346 opening is located on the top of the chamber 346 and just below the pellet dispensing mechanism 16. When triggered by electrical impulse, the gate 344 opens to allow the pellet into the chamber 346. The funnel 243 attached to trie gate 344 directs the pellet into the chamber 346. The valve 344 closes before the liquid reactant and waste are pumped into the chamber 346 through the fluid lines 347 and 349 connected to the chamber 346 on one end, and to the waste 24 and liquid reactant 18 containers on the other. The hydrogen gas produced exits the chamber 346 through one or more gas lines 350. Check valves can be installed on the liquid fluid lines to stop the liquids from flowing back into the chamber 346. An additional line for a pressure check valve may also be attached to the reaction chamber 346. Materials used for the chamber 346 and fluid lines are resistant to corrosion, operating pressure and temperature and may include plastics, plastic and polymer composites, metals and metal alloys.

[0066] The hydrogen gas exits the chamber 22 as it is produced and may pass through a liquid/gas separator 30 into a hydrogen container 32, and then to enter the fuel cell 34. The liquid/gas separator 30 can be made of a porous hydrophobic material with a function to eliminate any liquid from a hydrogen stream before it enters the hydrogen line and reaches the hydrogen overflow container 32 and fuel cell 34. However, due to the heat generated during the reaction hydrogen can carry a water vapor from the reaction mixture. The water vapor passes through the separator 30 and condenses in the gas line 350 and is carried by the hydrogen flow into the container 32 and fuel cell 34. To eliminate potential problems created by the presence of liquid water in the hydrogen stream, hydrogen can go from the chamber 22 to the waste container 24 and than to the container 32. (see e.g., Figure 3) The waste helps to cool hot and humid hydrogen and precipitate the excess water.

[0067] The hydrogen container 32 can also be collapsible and made of hydrogen impermeable materials such as plastics, plastic/foil laminates, fiber reinforced polymer laminates, or plastic impregnated composites resistant to pressure, temperature, and chemicals used in the system. In one embodiment, a pressure switch attached to the container 32 may control the amount of the stored hydrogen gas and protect the container from being over pressurized. When the pressure exceeds the set point, a pressure switch turns on a purge valve (not shown). However, in another embodiment, the hydrogen container 32 is further compressed by an elastic means. The elastic means comprise either rubber sheets or tubes or other spring mechanisms, but preferably latex rubber tube. In this embodiment, the size of the hydrogen container and spring constant of the compression mechanism is adjusted to develop the desired hydrogen pressure for the expected hydrogen volume produced by the reactants. In this way, the output pressure of the hydrogen system can be matched to the desired hydrogen pressure of the fuel cell or other hydrogen consuming device. [0068] As shown in Figures 2 and 3, in one embodiment, the reaction waste is removed from the reaction chamber 22 and 218 with a pump 28 or 220 into the waste container 24 and 224 after completion of each batch reaction that involves a particular chemical hydride dosage. On the other hand, the waste can be pumped back into the chamber 22 and 218 with the pump 26 and 222 after the pellet is in and the gate valve 344 is closed and before the liquid reactant is dispensed. However, the pumps 26 or 28 and 222 or 220 may be replaced by one pump only (not shown) that is able to operate in reversed directions. [0069] Typically, peristaltic, diaphragm, elastomeric, or any other appropriate pumps may be used in addition to valves combined with flow meters, switches or sensors. When it has a collapsible design, the waste container loses volume and occupies very little space when empty. This design allows filling the container with the liquid waste without any pressure differential. Typically, the waste container 24 and 224 and liquid reactant container 32 and 218 are packed together in a cartridge (not shown) that provides protection from mechanical damage to the containers 24, 32, 224, and 218 and enables a more compact system packaging. When both containers 24, 32, 224, and 218 are collapsible, practically the total volume of the waste in container 24, 32, 224, and 218 are approximately equal to the sum of the liquid and solid reactant volumes at the end of reaction. When both reactants are spent, they end up being waste and are stored in a waste container 24 and 224. [0070] In another embodiment, the waste container 24 and 224 may be made of a hard incompressible material. The container 351 itself is a cartridge lor both waste and liquid reactant at the same time. More specifically, the collapsible container 53 with the liquid reactant floats within a void space 352 in the cartridge 351 that is being filled with the waste as the reactants are spent. As with complementary volumes, the waste volume substitutes the liquid reactant volume lost during the device operation. The shape and size of the cartridge 351 can be adjusted to the system needs in order to optimize the volume and weight. However, in another embodiment, the liquid reactant container 18 and 114 may serve as the waste container when a semi-batch reaction occurs. Here, the waste is fully mixed with the unused liquid glycerol reactant after each reaction and is being collected within the same. [0071] Note that the waste container 24 or 224 may be made of a material that is chemically, mechanically, and thermally resistant at the system operating conditions. The container can be made of plastics, plastic composites, plastics reinforced with fibers, or plastic laminates. If necessary the container may also be made of corrosion resistant metals and metal alloys. Microcontrollers, sensors and switches can be utilized to control the operation of the hydrogen storage and generation device described. One of the possible controls embodiments is presented. The hydrogen system can be turned on manually or by a microcontroller to start hydrogen generation. A microcontroller (not shown) is electrically connected to the electrical components of the hydrogen generation device such as the pumps 26 and 26, the solenoid valve 348, the gate valve 344, and the brushless DC motor 337. It also turns on and off a pressure sensor and switches (not shown). In addition, wireless controls and data transmission may be implemented into the power electronics to remotely control and monitor the hydrogen system operation. The wireless data board may also include GPS for the purpose to know the fuel system location at any time. In operation, hydrogen is generated using a solid chemical hydride and liquid glycerol based reactant. As an example, sodium borohydride pellets are used as a solid reactant. When the system is turned on a microcontroller first checks hydrogen pressure and then activates the pellet dispenser 16. It rotates the take up spool 334 until a stop switch (not shown) is activated when a pellet is positioned on the dispensing roller 331 for the release from the strip package 312. With a small time delay, the gate valve 344 opens and the pellet is dispensed into the reaction chamber 22 and 218. The dispensing of the liquid reactant and waste starts after the gate vale 344 is closed. The reaction begins as soon as the pellet and the liquid get into contact. The reaction is typically slower at the beginning and accelerates within several minutes. The heat generated at the beginning of the reaction, increases the temperature of the reaction mixture and accelerates the hydrogen generation. Hydrogen, waste and water vapor are produced in this reaction. If the relative humidity of the hydrogen is concern, the gas is conveyed from the reactor to the waste container to separate excess water and then through a liquid/gas separator to hydrogen container and fuel cell (see Figure 3, for example). Hov/ever, if the humidity is not a concern, than hydrogen can bypass the waste container. [0072] As shown in Figure 1 1, the electrochemical performance, or polarization curve, of an open cathode convective PEM fuel cell fueled with hydrogen produced in embodiments according to aspects of the invention and with research grade hydrogen from a bottle are compared. No significant difference in the performance is observed between fueling the PEM fuel cell with a pure hydrogen sources and hydrogen produced by the disclosed embodiments. [0073] Although the hydrogen production systems have been described in connection with fuel cells, the apparatus and methods have other applications. For example, hydrogen gas is especially useful for various industrial processes and electrochemical energy conversion devices, such as devices that employ hydrogen fuel cells. Hydrogen fuel cells, depending on their size, shape, and configurai ion, can be relatively low or relatively high in power, and can be used for a variety of applications, such as for automobiles and for electronic devices. The hydrogen fuel cells can be light in weight. Hydrogen is also used for many chemical and industrial applications. For example, large quantities of hydrogen are used in the petroleum and chemical industries. One of the largest applications of hydrogen is for processing (or "upgrading") of fossil fuels. Common "consumers" of hydrogen in petrochemical plants include hydro-dealkylation, hydro-desulfurization, and hydro-cracking processes. Other uses of hydrogen include, but are not limited to, hydrogenation of fats and oils; manufacturing of hydrochloric acid; welding; reduction of metallic ores; rocket fuel; rotor coolant in electrical generators; and cryogenic research, e.g. superconductivity studies. It is to be appreciated that the present invention is not limited to any particular use of the hydrogen formed from the methods and apparatus disclosed. Further, depending on temperature and pressure conditions, the hydrogen may be in the form of gas or liquid. Typically, the hydrogen is in the form of gas as described herein, unless noted otherwise. [0074] The systems described above can be used to provide hydrogen production by many chemical processes. An exemplary set of methods according to aspects of the invention comprises the step of providing a reactor. The reactor can be any conventional reactor known in the art. Typically, the reactor is selected from the group of a batch reactor, a semi-batch reactor, and a continuous-flow reactor (CFR). Various reactor embodiments of the present invention are described in furth€ r detail below. It is to be appreciated that the method may be employed using a combination of two or more reactors, with the reactors being the same as or different than each other. [0075] The method further comprises the step of providing a hydrogen- generating composition to the reactor. The hydrogen-generating composition, hereinafter the composition, may be formed outside of the reactor and then introduced into the reactor, but more typically, individual components that make up the composition are introduced into the reactor and combined at some point in time to form the composition. As such, the reactor can generally include one or more inlets for providing the composition (and/or the components thereof) to the reactor. It is to be appreciated that a portion of the composition can first be formed outside of the reactor, such as in an inlet pipe or an outer storage tank, and a remaining portion of the composition can be formed inside the reactor. The reactor typically includes one or more outlets for removing the hydrogen gas from the reactor, during and/or after formation of the hydrogen gas. The outlet (or outlets) can also be used to remove components of the composition, the composition itself, and/or products other than hydrogen gas (e.g. by-products, which are described further below) from the reactor. It is to be appreciated the inlet and the outlet of the reactor can be one and the same, such as with a batch reactor system, however, the inlet and the outlet are typically different from each other, such as with a semi-batch reactor, a continuous-flow reactor, or other types of batch reactor systems. Flow rates of the inlet and outlet can be controlled by various methods known in the art, such as with pumps and/or valves attached thereto. As such, the reactor may be completely closed off during formation of the hydrogen gas, such as in a batch reaction process, or left partially open during formation of the hydrogen gas, such as in a semi-batch reaction process or continuous-flow reaction process. Depending on the specific reactor system employed, hydrogen can be produced in relatively small to relatively large quantities for later use, or can be produced when required for substantially instantaneous, use of the hydrogen. Several embodiments employing specific types of reactors and reactor systems are further described below in detail as an example of how this apparatus can be used for hydrogen generation from chemical hydrides. [0076] An exemplary composition can include or consists essential y of a borohydride component and a glycerol component. The composition may further include some amount of other components, as described further below, as long as such other components do not hinder formation of hydrogen gas from reaction between the borohydride and glycerol components, which is also described further below. In one embodiment, the composition consists of the borohydride corrponent and the glycerol component.

[0077] The borohydride component can comprise one or more conventional borohydrides known in the art. The borohydride component is generally of the simplified formula MB_xH_y, wherein M is typically a metal and subscripts x and y are typically integers, more typically subscript x is one (1) and subscript y is four (4). In certain embodiments, the borohydride is selected from the group of sodium borohydride (NaBH₄), lithium borohydride (LiBH₄), potassium borohydride (KBH₄), rubidium borohydride (RbBH₄), and combinations thereof; however, it is to be appreciated that other borohydrides may also be used, as described above. As shown in the formulas above, the borohydride component has hydrogen atoms; typically the borohydride component has four (4) hydrogen atoms. Suitable grides of borohydrides. for purposes of the present embodiments, are commercially jivailable from a variety of commercial suppliers. [0078] In one embodiment, the borohydride component can comprise sodium borohydride, which is also referred to in the art as sodium tetrahydroborate. This embodiment is especially useful because it is believed that the sodium borohydride has the highest specific hydrogen yield with the lowest specific energy release relative to other borohydrides, such as those described and exemplified above. Further, it is also believed that the sodium borohydride has excellent chemical and thermal stability relative to other borohydrides. For example, as understood in the art, sodium borohydride generally melts at ~400°C, and generally thermally decomposes at temperatures higher than ~400°C. Further, sodium borohydride is generally soluble in water and methanol; however, sodium borohydride tends to react with both unless a strong base is added to suppress solvalysis, specifically hydrolysis, as described above. Suitable grades of sodium borohydride, for purposes of the present invention, are commericially available from a variety of commerical suppliers. [0079] The borohydride component can comprise borohydride particles of various size and shape. Typically, the borohydride particles are in the foπn of a powder; however, the powder can also be confectioned into larger sizes and shapes, such as granules, beads, and pills. Generally, to facilitate reaction of the borohydride particles, increased surface area of the borohydride particles is preferred relative to borohydride particles having lower surface areas. Specifically, in certain embodiments, the borohydride particles have an average particle diameter of less than about 300 micrometers (μm), alternatively less than about 200 micrometers, alternatively less than about 100 micrometers.

[0080] Increased surface area and reduced particle size of the borohydride powder can be achieved by various methods. One example of a suitable method for obtaining higher surface area of the powder is to deagglomerate the borohydride particles by suspending the powder in a carrier fluid (or a non-solvent/hydrophobic media). Specifically, in certain embodiments, the borohydride component further comprises the carrier fluid. As such, when the carrier fluid is employed, the borohydride particles are suspended in the carrier fluid. If employed, the carrier fluid can be any conventional carrier fluid known in the art. Typically, the carriei fluid is selected from the group of mineral oil, petroleum jelly, saturated vegetable plant and animal oils and fats, non-saturated vegetable plant and animal oils and fats, and combinations thereof. In one embodiment, the carrier fluid is mineral oil. If employed as the carrier fluid, mineral oil can readily be recycled and recharged for subsequent use, as described further below. [0081] Another example of a suitable method for obtaining higher surf ice area of the powder is to grind the powder. Suitable apparatuses for grinding the powder include, but are not limited to, conventional ball mills, such as planetary ball mills. To prevent the borohydride particles from agglomeration, the powder is typically mixed with surfactants and/or dispersants, and then the borohydride particles are suspended in the carrier fluid, as described and exemplified above. The addition of surfactants and/or dispersants to the powder of the borohydride component also improves distribution of the borohydride particles during reaction thereof, which is described further below. If employed, the surfactant and/or the dispersant may be any type known in the art, and are commercially available from a variety of commercial suppliers.

[0082] The glycerol component comprises glycerol, which is also referred to in the art as glycerin, glycerine, propane- 1 ,2,3-triol, propane- 1,2,3-triol, 1,2,3- propanetriol, 1,2,3-trihydroxypropane, glyceritol, and glycyl alcohol. As understood in the art, glycerol is generally of the simplified formula CsHg(OITb. As shown in the aforementioned formula, the glycerol component has hydroxyl (OH) groups, and the hydroxyl groups have hydrogen atoms in addition to other hydrogen atoms of the glycerol. As understood in the art, glycerol is a polyol, specifically a triol or a trihydroxyl alcohol. Generally, glycerol is a colorless, odorless, sweet-tasting, syrupy liquid that melts at ~17.8°C, and boils with decomposition at ~290°C. Glycerol is generally miscible with water and other polar solvents. Glycerol is present in the form of esters (e.g. glycerides) in many animal and vegetable fats and oils. Glycerol can be obtained commercially as a by-product of animal and vegetable fat and oil hydrolysis. Glycerol can also be synthesized on a commercial scale from propylene produced by petroleum cracking. Recently, glycerol has been obtained as a byproduct of biodiesel production, which has favorable economic and environmental benefits, for purposes of the present invention. Due in part to many avenues of production, glycerol is commercially available from a wide variety of commercial suppliers. Further, cost of glycerol is expected to drop with increases in biodiesel production.

[0083] The exemplary method can further comprise the step of reacting the borohydride component with the glycerol component. Reaction of the components occurs in the reactor, once the components are contacted. Once the borohydride and glycerol components react, substantially all of the hydrogen atoms present in the borohydride component and substantially all of the hydrogen atoms present in the hydroxy! groups of the glycerol component are converted to form the hydrogen gas. The reaction between the borohydride component and the glycerol is a solvolysis reaction; more specifically the reaction between the borohydride component and the glycerol is an alcoholysis reaction. An example of an alcoholysis reaction between the sodium borohydride (as the borohydride component) and the glycerol is illustrated below by simplified Reaction Scheme II. Reaction Scheme II: 3 NaBH₄ + 4 H₅(COH)₃ -» 4 H₂(g) T + (NaB)₃(H₅(CO)₃)4 + heat

[0084] As illustrated by Reaction Scheme II above, the alcoholysis reaction is generally a spontaneous exothermic reaction of the sodium borohydride and the glycerol component that produces hydrogen gas, heat, and a by-product, i.e., a sodium borate complex ((NaB)₃(H₅(CO)₃)₄). In other words, the sodium borate complex is a reaction product of the borohydride component and the glycerol component. The sodium borate complex can be referred to as a metal glycerolate, here as a sodium glycerolate. The reaction product, e.g. the sodium borate complex, can be separated, collected, and sold after forming the hydrogen gas, if so desired. It is important to note that all hydrogen atoms present in the sodium borohydride and all of the hydrogen atoms present in the hydroxyl groups of the glycerol are converted into the hydrogen gas. Specifically, as alluded to above, generally, the alcoholysis reaction of the present invention yields 100% hydrogen from the hydrogen atoms of the borohydride component and the hydrogen atoms of the hydroxyl groups of the glycerol component.

[0085] Generally, chemical conversion in the alcoholysis reaction is localized at a phase interface. Specifically, a boundary layer formed at a solid surface of the borohydride particle, e.g. a sodium borohydride particle, consists of a saturated solution of the reaction products, e.g. the sodium borate complex and for a period of time, the hydrogen gas. Limiting factors for the alcoholysis reaction include a diffusion rate of the glycerol component and the size of surface area of borohydride component, as introduced above. Various steps for reducing these limiting factors are further described below. [0086] Theoretical hydrogen storage capacity for the alcoholysis reaction can be calculated based on Reaction Scheme II. In the alcoholysis reaction, the weight of the sodium borohydride is 38 grams/mole, and the weight of the glycerol that reacts with the sodium borohydride is 122 grams (1.33 moles of glycerol per 1 mole of the sodium borohydride), the total reactant weight (i.e., the composition weight) is 160 grams. Since 8 grams (or 4 moles) of hydrogen is released, the theoretical hydrogen storage capacity is calculated as 8 grams over 160 grams, or 5.0 % by weight of the composition. To sustain continuous hydrogen formation, three (3) moles of the borohydride component, e.g. sodium borohydride, needs to react with four (4) moles of glycerol, continuously. As such, the composition, prior to reaction, generally includes the borohydride component and the glycerol component in a three (3) to four (4) stoichiometric ratio relative to one another. In certain embodiments, to insure that the borohydride component fully reacts during the alcoholysis reaction, i.e. to insure that the borohydride component is fully "used up", the glycerol component is present in the composition in a stoichiometric excess relative to the borohydride component, prior to reaction. In other embodiments, the borohydride component and the glycerol component may be in other stoichiometric ratios relative to one another, depending on how much hydrogen formation is desired. It is to be appreciated that a similar alcoholysis reaction with the glycerol component can occur with borohydrides other than sodium borohydride, as described and exemplified above, which will yield a different borate complex by-product, i.e., different metal glycerolates, and different amounts of hydrogen based on their respective hydrogen storage capacity. It is also to be appreciated that the borohydride component can include a combination of two or more of the aforementioned borohydrides. [0087] It is believed that the alcoholysis reaction, as illustrated above by Reaction Scheme II, involves two primary steps to form the hydrogen gas. The first step of the two involves protonation of the borohydride component, which is illustrated below by simplified Reaction Scheme III. Reaction Scheme III:

[BH₄]^" + H₅(COH)₃ -> H₂BH₃ + H₅(COH)₂(CO)^' [0088] As illustrated above by Reaction Scheme III, the first step involves protonation of the borohydride component with a proton from the glycerol component. It is believed that in the presence of a strong basic group such as a borohydride anion (i.e., the [BH₄]^" of the borohydride component), the glycerol component behaves as a Lewis acid and can lose protons from its hydroxyl groups. It is further believed that the proton from the glycerol component creates an unstable intermediate (i.e., BH₂BH₃).

[0089] The second step of the two involves foπnation of hydrogen, as illustrated below by simplified Reaction Schemes IV and V. Reaction Scheme IV:

H₂BH₃ -> H₂(g) t + BH₃ Reaction Scheme V:

BH₃ + H₅(COH)₃ -* H₂(S) T + BH₂[H₅(COH)₂(CO-)] [0090] As illustrated above by Reaction Scheme IV, the unstable intermediate decomposes into a hydrogen molecule and an unstable borohydride (i.e., BH₃). This unstable borohydride may further deprotonate another molecule of the glycerol component creating an additional hydrogen molecule and a boron glycerolate complex (BH₂[H₅(COH)₂(CO-)]) as illustrated above by Reaction Scheme V. [0091) It is believed that both of the hydrogen forming steps of the second step illustrated above in Reaction Schemes IV and V are fast relative to the first step illustrated in Reaction Scheme III. It is believed that the difference in reaction rate is due predominantly to the presence of the unstable intermediate compounds (H₂BH₃ and BH₃). As such, the first step is the rate determining step for the overall alcoholysis reaction. The practical meaning of the first step is that by changing the rate of this first step, the overall reaction rate of the alcoholysis reaction changes, thereby resulting in different hydrogen generation rates. Various methods of changing the rate of the alcoholysis reaction, i.e., a rate of formation of the hydrogen, are described and illustrated below. [0092] The method can further comprise the step of altering temperature of at least one of the reactor and the composition. In other words, the reactor can have its temperature altered, the composition can have its temperature altered, or both the reactor and the composition can have their temperatures altered. Temperature of the composition may be adjusted by heating or cooling the composition itself, and/or by heating or cooling an individual component (or components) thereof prior to forming and/or during formation of the composition. It is to be appreciated that one or more of the components may be heated and/or one or more of the components may be cooled prior to forming the composition. By altering temperature, the rate of formation of the hydrogen gas can be adjusted. Generally, increasing the temperature increases the rate of formation of hydrogen, while decreasing the temperature decreases the rate of formation of the hydrogen. Heating and cooling can be accomplished by various methods known in the art, such as by the use of one or more heat exchangers. For example, the reactor may include a heat exchanger to control its temperature or a storage vessel containing one of the components, e.g. the glycerol component, can include a heat exchanger. Heating and cooling of the composition can also be accomplished internally by the addition of various active or passive compounds into the reaction composition. For example, reaction acceleration can be achieved by adding a small amount of acetic acid that reacts with sodium borohydride hydride, instantaneously generating heat high enough to provide enough energy to accelerate hydrogen generation. However, to slow down the hydrogen generation rate, reaction waste can be added into the reaction mixture to absorb the excess heat and thus cool the reaction composition. [0093] Viscosity of the composition can also be altered by heating or cooling the composition, as described and exemplified above. Generally, heating the composition decreases viscosity of the composition and cooling the composition increases viscosity of the composition. Typically, increasing the viscosity decreases the rate of formation of the hydrogen and decreasing the viscosity of the composition increases the rate of formation of the hydrogen, by increasing the diffusion rate of the glycerol component. For example, an increase of temperature from 2O⁰C to 4O⁰C causes viscosity of the glycerol component to drop by almost a factor of 5 (e.g. dropping from -1 ,410 centipoise to -284 centipoise). Alternatively, the viscosity of the glycerol component can be changed by dilution of the glycerol component. Examples of suitable diluents include water and alcohol. However, any other diluent known in the art that has lower or higher viscosity than the glycerol component and is miscible with the glycerol component can be used to modify the viscosity of the glycerol component. In certain embodiments, the method can further comprise the step of providing a surfactant component to the reactor, thereby altering viscosity of the hydrogen-generating composition. If employed, the surfactant component can comprise any type of surfactant known in the art. As described above, the borohydride component may already include a surfactant to prevent agglomeration of the borohydride particles. Suitable surfactants, for purposes of the present invention, are available from a variety of commercial suppliers.

[0094] The method can further comprise the step of altering pressure of the reactor. Pressure can be altered by various methods known in the art, such as by changing flow rates of the components fed to the reactor, changing flow rates of products removed from the reactor, e.g. the hydrogen, or by changing a volume within the reactor. Altering pressure in the reactor is useful for adjusting the rate of formation of the hydrogen. Generally, increasing pressure in the reactor increases the rate of formation of the hydrogen and decreasing pressure in the reactor decrease the rate of formation of the hydrogen. [0095] The method can further comprise the step of providing a pH component to the reactor. The pH component can be provided separate from the borohydride and glycerol components, or included with one of or both of the borohydride and glycerol components in water containing reactions. The pH component is useful for adjusting the rate of formation of the hydrogen gas. The pH component can comprise at least one of an acid, a base, and a buffer. The acid, base, or buffer can comprise any acid, base, or buffer known in the art. Generally, the acid, base, or buffer respectively increases, decreases, or maintains the rate of foπnation of the hydrogen gas. Suitable acids, bases, and buffers, for purposes of the present invention, are available from a variety of commercial suppliers. [0096] In one embodiment, the pH component comprises acetic acid, which can be concentrated or diluted, e.g. 5% by weight acetic acid in water. This embodiment useful for increasing the rate of foπnation of the hydrogen gas. Typically, the borohydride component will react with the acid, if employed as the pH component. In such a reaction, generally hydrogen gas and triacetoxyborohydride (NaBH(CH3COO)3) are formed (when sodium borohydride is employed as the borohydride component). Such a reaction between the borohydride component, e.g. sodium borohydride, and the acid is also generally highly exothermic. As such, heat generated during such the exotheπnic reaction can be used to trigger the alcoholysis reaction since the reaction rate of the alcoholysis reaction can be suppressed or enhanced by changing temperature, as described and exemplified above. If employed, the pH component can be used in various amounts, based on how much the rate of formation of hydrogen is desired to be changed. As such, suitable amounts of the pH component and corresponding rates of reaction can be determined via routine experimentation by one skilled in the art.

[0097] The method can further comprise the step of providing a catalyst component to the reactor. The catalyst component can be provided separate from the borohydride and glycerol components, or included with one of or both of the borohydride and glycerol components. The catalyst component is useful for adjusting the rate of formation of the hydrogen gas, typically, if employed, for increasing the rate of formation of the hydrogen gas. The catalyst component facilitates heterogeneous catalysis of the alcoholysis reaction. The catalyst component can comprise one or more conventional catalysts known in the art. Suitable grades of catalyst, for purposes of the present invention, are available from a variety of commercial suppliers.

[0098] If employed, the catalyst component is typically a solid catalyst. The catalyst component can be in various forms, such as a finely dispersed powder, pellets, or particles. These forms of the catalyst component can be suspended in the glycerol component (i.e., the glycerol component serves as a carrier fluid). The catalyst component is typically selected from the group of carbon-based catalysts, platinum-based catalysts, palladium-based catalysts, ruthenium-based catalysts, titania-based catalysts, and combinations thereof. In one embodiment, the catalyst component comprises activated carbon. This embodiment useful for increasing the rate of formation of the hydrogen gas. Further, activated carbon is generally inexpensive, bio-derived, and biodegradable. Specifically, low catalyst cost and preparation from renewable sources allows for discarding of the activated carbon along with the reaction by-product or recycling of the activated carbon by filtration, washing and drying. If employed, the catalyst component can be used in various amounts, based on how much the rate of formation of the hydrogen is desired to be changed. As such, suitable amounts of the catalyst component and corresponding rates of reaction can be determined via routine experimentation by one skilled in the art. [0099] The method can further comprise the step of recycling the carrier fluid (if employed, as previously described and exemplified with description of the borohydride component) from the reactor after the step of reacting the borohydride component with the glycerol component. This step is useful for incorporating additional borohydride particles into the recycled carrier fluid. As such, the "recharged" and recycled carrier fluid can be subsequently used for providing additional amounts of the borohydride component to the reactor for further formation of hydrogen. A semi-batch reaction system employing such a step is described below. [00100] In certain embodiments, the method further comprises the step of providing water to the reactor. The water is useful for decreasing viscosity of the hydrogen-generating composition. Further, the water can also react with the borohydride component to form hydrogen; however, such a reaction is generally disfavored due to issues with increase in pH. As such, in certain embodiments, the composition is substantially free of water. In these embodiments, the composition typically includes water in an amount of less than 50, more typically less than about 25, yet more typically less than about 15, most typically less than about 5, and yet most typically equaling or approaching about 0, parts by weight, based on 100 parts by weight of the composition. It is to be appreciated that one or more of the components may include trace amounts of water. In one embodiment, the composition is completely free of water, i.e., the composition is anhydrous. [00101] The method can further comprise the step of mixing the composition contemporaneously with the step of reacting of the borohydride component with the glycerol component. This step of mixing is useful for increasing a rate of formation of the hydrogen gas. Specifically, the diffusion limitations of the alcoholysis reaction can be reduced through mixing, stirring, or physical manipulation of the composition such that convective mass transport becomes a dominating flow effect. Generally, mixing greatly enhances the rate of reaction of the glycerol component with the borohydride component. Mixing of the composition can be accomplished in various ways, such as by a mixing blade disposed in the reactor or by some other form of agitation known in the art. For example, the components can be mixed via spraying when being introduced into the reactor. Further, mixing can be achieved not only through external means, e.g. a mixing blade, but also by taking advantage of temperature generation to promote natural convection of the composition within the reactor. [00102] Generally, the method further comprises the step of removing the hydrogen gas from the reactor after (and/or during) formation of the hydrogen gas. Also, the method generally comprises the step of storing the hydrogen gas removed from the reactor. The hydrogen gas can be stored in a storage vessel or stored directly in an end product, such as a hydrogen fuel cell. [00103] As introduced above, various types of reactors, and therefore various types of reactor systems can be employed to the present invention. In one embodiment, the reactor is a batch reactor. In this embodiment, as introduced above, stoichiometric quantities of the components of the alcoholysis reaction are provided to the reactor at the same time to form the composition. Batch reactors allow for the alcoholysis reaction to be completed, albeit at a decreasing rate in time.

Claims

CLAIMS What is claimed is:

1. A hydrogen production system for forming hydrogen gas composition comprising: i. a first container for storing a hydride component; ii. a second container for storing a liquid reactant component; iii. a reactor device cooperable with said first container and said second container; iv. a dispenser cooperable with at least one of said first container and said second container and with said reactor device for selectively dispensing at least one of the hydride corr ponent and the liquid reactant component to said reactor device; and v. said reactor device permitting reaction of the hydride component with the liquid reactant component thereby converting substantially all of hydrogen atoms present in the hydride component to form a hydrogen gas composition.

2. A hydrogen production system as set forth in claim 1 , wherein the hydrogen gas composition consisting essentially of a borohydride component and the liquid reactant component is a glycerol component in a generally three to four stoichiometric ratio, the borohydride component having the hydrogen atoms and the glycerol component having hydroxyl groups.

3. A hydrogen production system as set forth in claim 2, including individual dosages of dry solid chemical hydride packaged in heat sealed, impermeable and chemically resistant materials.

4. A hydrogen production system as set forth in claim 3, wherein the individual packages of dry solid chemical hydride are connected in continuous strips or heat sealed punch cards.

5. A hydrogen production system as set forth in claim 2, wherein the individual packages with the amount of the dry solid chemical hydride can be selectively scaled up or down, depending on the amount of hydrogen selectively required to be stored or generated for use.

6. A hydrogen production system as set forth in claim 1, further including a reaction waste container.

7. A hydrogen production system as set forth in claim 1, further including a pump for dispensing the liquid reactant.

8. A hydrogen production system as set forth in claim 1, further including a hydrogen overflow container.

9. A hydrogen production system as set forth in claim 1, further including a liquid gas separator.

10. A hydrogen production system as set forth in claim 2, wherein the borohydride component comprises sodium borohydride (NaBH₄).

1 1. A hydrogen production system as set forth in claim 1, wherein the hydrogen generation is water independent.

12. A hydrogen production system as set forth in claim 2, wherein the borohydride component is selected from the group of sodium borohydride (NaBH₄), lithium borohydride (LiBH₄), potassium borohydride (KBH₄), rubidium borohydride (RbBH₄), and combinations thereof.

13. A hydrogen production system as set forth in claim 1 , wherein said reactor device alters temperature of the hydrogen-generating composition thereby adjusting a rate of formation of the hydrogen gas composition.

14. A hydrogen production system as set forth in claim 1, wherein said reactor device adjusts a rate of formation of the hydrogen gas composition.