JP2007520410A - Fuel blend for hydrogen generator - Google Patents

Abstract

The present invention relates to improved aqueous fuels for hydrogen generators and methods for using them in the production of hydrogen. The present invention also relates to a system that uses the subject aqueous fuel to generate hydrogen gas for use in fuel cells or other devices. The subject fuels include a mixture of boron hydrides, at least one of which is a metal salt, including metal borohydrides, higher boranes and higher metal boron hydrides. The subject aqueous fuel comprises a mixture of boron hydrides having a cationic charge ( ⁺ IC) to boron ratio of between 0.2 and 0.4, or between 0.6 and 0.99. Preferred fuels comprise a mixture of boron hydrides having a ( ⁺ IC) to boron ratio between 0.2 and 0.3 or between 0.7 and 0.8. Mixtures containing metal borohydrides also contain metal hydroxides for their stabilization against premature hydrolysis in aqueous fuel media.

Description

  The present invention relates to blends of borohydride salts used for hydrogen generation.

Various boron hydrides (hereinafter referred to as borohydrides), particularly their metal salts, have been known for about 50 years to be useful for the generation of hydrogen. Schlesinger et al., “Sodium Boroidide: Its Hydrolysis and Its Use in a Redundant Agent in the Generation of Hydrogen,” Am. Chem. Soc. 75, 215-219, 1953, and G. W. Parshall, "Hydrogen Generation by Alcoholosis of a Polyhydropolyborate-Group 3 VIII, Met., Vol.16, Met. Vol.16, Met. It has also been recognized that hydrogen generation is generally carried out by acid or metal catalyzed hydrolysis, as reported in. This early work has been improved by the development of systems that control hydrogen generation as needed. U.S. Pat. No. 6,534,033 describes Formula 1
MBH ₄ + 2H ₂ O → 4H ₂ + MBO ₂ (1)
By contacting the aqueous solution by pumping an aqueous solution of borohydride through a chamber containing a metal catalyst that converts the borohydride into hydrogen gas and borate in an approximately quantitative yield according to It is described to control the occurrence of.

  There are several factors that determine the choice of a particular borohydride salt for use in the method shown in Equation 1. Of these, solubility in water is most important. Borohydrides generally have a solubility in water of about 7 to about 35% by weight at 25 ° C. Lithium borohydride has a solubility of 7%, potassium borohydride is about 19%, and sodium borohydride is about 35% soluble. For this reason, and for several other reasons, particularly including safety and convenience, sodium borohydride is the optimal salt for a hydrogen generator fuel solution. Sodium borohydride having a high weight hydrogen storage density of about 7.4% by weight of saturated solution at ambient temperature is also preferred in the practice of this invention.

  In a concentrated solution of sodium borohydride, as described above, sufficient water is initially present to complete the hydrolysis of the sodium borohydride and maintain the borate product as a solution. However, as hydrolysis proceeds and water is consumed as shown in Equation 1, the amount of water present and available to maintain the borate product as a solution decreases. If the amount of water in the system decreases to the point where the borate precipitates out of solution in the catalyst reactor or in any piping that connects the storage tank to the reactor, the hydrogen generator will shut it down and decompose And should gradually close to the point where it must be cleaned.

  As a result of the potential for borate product to precipitate out of solution, the concentration of sodium borohydride in the hydrogen generating fuel solution is between about 15% and 20% by weight despite its relatively high solubility. Limited. Such a solution accounts for about 4.25% by weight of the evolved hydrogen. This has been recognized as a practical limit for hydrogen generation, for example, Von Dohren, “Raney Catalyst for Generating Hydrogen of Decomposition of Borane”, US Pat. No. 3,615,215. Please refer to the specification. This constraint results in a corresponding reduction in hydrogen storage capacity and will not be considered optimal in those situations where volume is important. Typically, the situation is such and it is particularly desirable to have a hydrogen dense fuel that maximizes the amount of hydrogen stored per unit volume of fuel. The present invention provides such a fuel.

According to the invention, a mixture of borohydrides comprising at least one borohydride salt having a cation selected from the group consisting of alkali metal cations, alkaline earth metal cations, aluminum cations and ammonium cations. A hydrogen generating fuel blend comprising a mixture having a predetermined molar ratio of solvated cationic charge ( ⁺ IC) to boron atoms, thereby maximizing the solubility of the borate. provide. Such a fuel blend alleviates the problem of premature solidification of the borate product in the hydrogen generator and makes it easier to achieve a fuel with a high weight hydrogen storage that can be utilized for hydrogen generation. To do. A fuel blend corresponding to a solution having between 30% and 38% by weight sodium borohydride, and thus a weight hydrogen storage density between 6.4% and 8% by weight, without the disadvantages of known fuels It can be hydrolyzed effectively to produce hydrogen. The fuel blends described herein are also utilized to provide improved methods and systems for hydrogen generation.

(Detailed description of the invention)
The present invention relates to an aqueous hydrogen generating fuel comprising a certain mixture of boron hydrides. Boron hydride in this context refers to borane including polyhedral borane and anions of borohydride or polyhedral borane. More particularly, the present invention relates to aqueous fuels containing blends of boron hydrides having a predetermined molar ratio of solvated cationic charge ( ⁺ IC) to boron atoms. It has been found that this ratio results in maximizing the solubility of the borate product of the hydrolysis reaction that occurs during hydrogen evolution rather than the components of the fuel. In this context, solubility is maximized to achieve optimal solubility of the borate product in relation to the concentration of borohydride in the fuel, and thus, for example, shown in the borohydride of formula (1) As such, it means minimizing the rate of precipitation of borate product during hydrogen evolution as a result of water consumption during the hydrolysis of borohydride.

The ratio of cationic charge (+ IC) to boron is determined by the present invention as follows, for example using an alkali metal salt. Alkali metal borates are typically written with the formula jM ₂ O · kB ₂ O ₃ · XH ₂ O, where M is selected from lithium, sodium and potassium. The values of j, k and X are different for various borates. For example, inorganic borax has j = 1, k = 2 and X = 10, therefore can be written as _{Na 2 O · 2B 2 O 3} · 10H 2 O or _{Na 2 B 4 O 7 · 10H} 2 O . One skilled in the art will recognize that solid crystal borates are formed at almost any ratio of j to k, but the solubility of such crystals in water will vary. There are two maximum values of temperature dependent solubility, appearing at a j to k ratio between 0.2 and 0.4 and again at a ratio between 0.6 and 0.99.

  The solubility of borate as discussed above as a function of the value of the j to k ratio has been known for many years. For example, Nies and Holbert, Journal of Chemical and Engineering Data, Vol. 12, No. 3, pp. 303-313, 1967, Adams, “Boron, Metallo-Boron Compounds and Boran”. John Wiley & Sons, p. 81, 1964 and Garret, “Borates, Deposits, Processing, Properties and Applications Handbook” (Academic Press, 1998, Borates, Handbook of Deposits, Processing, Properties and Use). Please refer. Salts of the above formula where M is potassium or lithium have similar solubility maxima, Adams supra, pages 81 and 83, Reburn and Gale, Journal of Physical Chemistry, Vol. 59, No. 19, 1955 . Such values, along with myriad others, have been available in the published literature for many years, but these values have not been previously recognized in the determination of hydrogen generator fuel blends.

According to the present invention, the hydrogen generator fuel blend has a value of the molar ratio of cationic charge ( ⁺ IC) to boron atoms of between 0.2 and 0.4, preferably between 0.2 and 0.3. Or a mixture of boron hydrides such as between 0.6 and 0.99, preferably between 0.7 and 0.8. The fuel mixture according to the present invention provides a desired ratio when the cation (M) is combined with a borohydride selected from alkali metals such as sodium, lithium, potassium, alkaline earth metals, aluminum or ammonium. Of at least one other boron hydride salt. Suitable boron hydrides include, but are not limited to, borohydride salts (MBH ₄ ), triborohydride salts (MB ₃ H ₈ ), decahydrodecaborate (M ₂ B ₁₀ H ₁₀ ), Tridecahydrodecaborate (MB ₁₀ H ₁₃ ), dodecahydrododecaborate (M ₂ B ₁₂ H ₁₂ ) and octadecahydroicosaborate (M ₂ B ₂₀ H ₁₈ ) and decaborane (14 ) There is a group of similar neutral borane compounds (M is an alkali metal, alkaline earth metal or aluminum cation) compatible with boron hydride salts such as (B ₁₀ H ₁₄ ).

It is within the scope of the present invention to utilize a mixture of such higher boron hydrides to achieve the desired cationic charge ( ⁺ IC) to boron atom molar ratio. Such a mixture can contain boranes such as those described above, but must also have at least one boron hydride salt so that the desired ( ⁺ IC) to boron ratio is obtained. Preferred mixtures of cationic borohydrides according to the present invention include, but are not limited to, metal borohydride salts, preferably sodium borohydride and decaborane (14); metal triborohydride salts and metal dodecahydro There are dodecaborate salts; metal borohydride salts and metal triborohydride salts; and metal borohydride salts and metal dodecahydrododecaborate salts. Both are advantageous if the mixture of boron hydrides in the target fuel has a ⁺ IC / B ratio that falls between 0.2 and 0.4 or between 0.6 and 0.99. As it is, it has no significant meaning. The selection of the component borohydride and the resulting ⁺¹ C / B ratio is a matter of economic considerations, such as the relative availability and cost of individual boron hydride compounds, and individual It is determined by considerations of the chemical reactivity of borohydride compounds and their effects on human health. Which is a particular mixture can be determined by other considerations, such as the relative solubility of the various borohydrides, the desired operating temperature range of the mixture, and is considered within the authority of those skilled in the art. It is done.

The cationic component of the higher borohydride can be an alkaline earth metal cation or an aluminum cation in addition to the alkali metal cation, as described in the reference to borohydride. Preferably, the cation is selected from sodium, lithium, potassium, beryllium, magnesium, calcium or aluminum. If the target fuel mixture contains more than one borohydride salt, it is not a requirement that these cation components be the same. As noted above, the cationic component of the metal borohydride of the subject fuel blend is preferably sodium. One skilled in the art will recognize that when a borohydride salt is present in a hydrogen generator aqueous fuel mixture, it is easily hydrolyzed if it is not stabilized against hydrolysis by the presence of a strong base. I will. Suitable bases for this purpose are the abovementioned individual metal hydroxides which are strong bases, for example sodium hydroxide if this component is sodium borohydride. In preferred fuel mixtures according to the invention containing borohydride salts, the positive cation component of the stabilizer must be in the formula when calculating the molar ratio of cationic charge ( ⁺ IC) to boron as described below . Similarly, in order to prepare a stable aqueous solution of decaborane (14), an alkaline stabilizer must be present; the metal cation component of the stabilizer imparts a cationic charge ( ⁺ IC) to the fuel blend. . Many of the boron-rich hydrides (such as M ₂ B ₁₂ H ₁₂ , M ₂ B ₁₀ H ₁₀ and M ₂ B ₂₀ H ₁₈ ) are stable in neutral aqueous solutions.

According to the present invention, the calculation of the molar ratio of cationic charge ( ⁺ IC) to boron is developed as follows. By way of example, an aqueous fuel solution containing 35% by weight sodium borohydride as a single cationic boron hydride with 3% by weight sodium hydroxide added for stability would be, for example, 100 grams of fuel. The solution has a j: k ratio of 1.08 determined as follows. In this example, all boron is derived from sodium borohydride, so the number of moles of boron is calculated directly from the borohydride concentration in the fuel solution as shown below.

Using similar calculations, it can be seen that sodium borohydride provides 0.925 moles of Na as well. This is because sodium and boron are present therein in a 1: 1 molar ratio. However, there is additional sodium ( ⁺ IC) supplied from the sodium hydroxide stabilizer, which can be determined in a manner similar to the determination of boron contribution, as shown below.

したがって、３５重量％の水素化ホウ素ナトリウム及び３重量％の水酸化物ナトリウムを含有する溶液は、１．０８の（^＋ＩＣ）対ホウ素比を有することになり、これは、上述の最大限の溶解度範囲の比の範囲外にある。このことは、反応が続くにつれて、ホウ酸塩生成物が依然として溶液として残り、沈殿して装置の目詰まりを生じさせないことを確実にするために追加の水を投入することなく、水素発生器中にこのような濃厚な燃料溶液を使用することを事実上制限することになる。 Knowing the mole of sodium corresponding to the cation charge ( ⁺ IC), this ratio can be calculated by dividing the total mole of sodium by the total number of moles of boron, as shown below.

Thus, a solution containing 35 wt% sodium borohydride and 3 wt% sodium hydroxide would have a ( ⁺ IC) to boron ratio of 1.08, which is the maximum It is outside the range of the solubility range ratio. This means that as the reaction continues, the borate product still remains in solution and precipitates in the hydrogen generator without adding additional water to ensure that it does not clog the equipment. The use of such a concentrated fuel solution is effectively limited.

  As noted above, the presence of higher borohydrides in the fuel solution will adjust the j to k ratio to lower to the preferred ratio of the present invention. This is because higher borohydrides are rich in boron relative to the metal components of the fuel mixture. The solubility of the product borate from such fuels is significantly higher than conventional aqueous sodium borohydride solutions, thus reducing the risk of borate product solidification and increasing the amount of borohydride in the fuel solution. And therefore higher amounts of hydrogen. Another advantage of the fuel mixture of the present invention is that many of the higher boron-rich higher borohydrides are stable in aqueous solutions, as in the case of metal borohydrides such as sodium borohydride. No addition is necessary. Another advantage of the subject blended fuel solution is that some higher boron hydrides are hydrolyzed in aqueous solutions to produce some acidic products, which in turn are present in any metal hydroxide present. Less basic than metal metaborate / metal hydroxide mixtures obtained from using fuels containing only metal borohydrides and metal hydroxides It should produce an exhaust stream.

  Another advantage of the novel aqueous fuel blend of the present invention is the fact that the product is readily water soluble, even if cooling occurs and some solidification occurs in the hydrolysis reactor. In contrast, borate mixtures that are formed when the fuel contains only metal borohydrides and hydroxides, such as sodium borohydride and hydroxide, are slow to dissolve and are contained in the catalyst chamber. It can form crusts that are difficult to remove. The borate mixture formed using the fuel mixture of the present invention is easily removed by a simple means of flushing the chamber and associated equipment with water, thereby extending catalyst life and reducing the normal life of the hydrogen generation system. Maintenance downtime can be shortened. The ease of cleaning and the increased interval at which cleaning and maintenance operations of the hydrogen generation system are required are another practical advantage of the fuel mixture of the present invention.

Compared to fuel mixtures containing only metal borohydrides, such as sodium borohydride, an explanation for the solubility difference between products formed from the fuel mixture of the present invention is typically accompanied by borates It is in the negative heat of solvation. For example, sodium metaborate exhibits substantial cooling of the solvent when in solution, thereby slowing the dissolution reaction. In contrast, sodium borate salts with a molar ratio of cationic charge ( ⁺ IC) to boron, which are within the maximum solubility range according to the present invention, can have a solvated positive calorie, and thus the dissolution reaction and This actually promotes the production of hydrogen. See O'Brien et al., “Amorphous Sodium Borate Composition”, US Pat. No. 2,998,310.

  As used herein, the term “aqueous fuel” includes an aqueous solution in which all components are dissolved and / or a slurry that is a solid in which some components are dissolved and some components are not dissolved. Hydroalcoholic mixtures are also advantageous in preparing the aqueous fuels of the present invention in that they lower the freezing point of the fuel, thereby extending their operating temperature range. In general, higher boron hydrides tend to be soluble and stable in aqueous alcoholic solutions, especially when stabilizers are present to raise the pH. The alcohols used to prepare the aqueous alcohol solution are lower alkanols, particularly methanol and ethanol. In this specification, an aqueous fuel prepared in the form of a slurry for ease of handling and storage economy is used to form a solution of ingredients that ensures the maximum solubility ratio presented herein. It is contemplated to mix with sufficient water at the time of use.

In accordance with the present invention, an improved method and system for generating hydrogen is provided. This method facilitates the hydrolysis of boron hydride to produce hydrogen in an improved aqueous fuel blend directed to a boron hydride having a specific cationic charge ( ⁺ IC) to boron molar ratio Contacting with a catalyst. This system provided by the present invention includes means for contacting an aqueous fuel blend of borohydride with a catalyst. Such means include means for physically separating the catalyst from the fuel when there is no demand for hydrogen gas. When there is a demand for hydrogen, the aqueous fuel solution can be contacted with a catalyst so that a hydrolysis reaction occurs and hydrogen is produced. This separation of the catalyst can be achieved by using any mechanical, chemical, electrical and / or magnetic method that can be readily understood by those skilled in the art. In one embodiment, a different chamber is used to separate the catalyst from the aqueous fuel solution. This aqueous fuel can be stored in a fuel reservoir from which it can be pumped into contact with the catalyst and thereby contact the catalyst with hydrogen by a hydrolysis reaction illustrated in equation (1) for metal borohydrides. Is generated. In an alternative embodiment, the catalyst can be inserted into and removed from a tank containing the hydride solution of interest.

  In other embodiments, the catalyst for hydrolysis is an acid, and the fuel and catalyst are both liquid and can be pumped into the reaction chamber to generate hydrogen. In this embodiment, the fuel and catalyst solutions must be stored in separate containers and individually pumped into the reactor to initiate and maintain the hydrolysis reaction. Preferred acid catalysts are strong inorganic acids, especially hydrochloric acid, sulfuric acid and phosphoric acid.

  The improved fuel solution of the present invention may be pumped into the system either batchwise or continuously. Further, the catalyst chamber can comprise at least one conduit through which the fuel solution can be directed into and out of the chamber at various stages of the catalytic reaction. This conduit can also serve as a product flow path for discharging hydrogen gas generated by the hydrolysis reaction.

  A separate chamber, if an insoluble metal or metal bound, confined therein and / or coated thereon is used as the catalyst in the reaction illustrated in Formula (1) It is important to note that can be unnecessary. Suitable substrates for the metal catalyst include, but are not limited to, plastics, polymers, fibers, metals, metal oxides, ceramics, or carbonaceous materials. In a preferred embodiment, the system of the present invention is on a porous or non-porous substrate including a metal mesh and metal fibers as shown in US Pat. No. 6,534,033, incorporated herein by reference, and ( Or) includes a retention system in which the catalyst is confined by physical or chemical means. In any of these embodiments, the hydrogen generation system allows the separation of the catalyst from the aqueous fuel to remove the insoluble or supported catalyst from the solution, thereby contacting the catalyst and the boron hydride therein. There can be only one chamber that can be achieved by blocking the. Thus, if hydrogen production is required, this catalyst can simply be reinserted into the aqueous fuel to catalyze the above reaction (1).

  Since the improved aqueous fuel of the present invention is stable in the absence of a catalyst, the generation of hydrogen by reaction (1) is closely controlled by adjusting the contact between the boron hydride and the catalyst therein. Can be controlled. This control can be achieved by adjusting the flow rate of the aqueous fuel to the catalyst, or by removing the catalyst from the fuel solution, depending on the actual settings of the hydrogen generation system and their configuration. In systems that use supported or deposited catalysts, hydrogen production can be controlled by contacting or separating the bound catalyst from the borohydride fuel solution. For example, the catalytic metal can be coupled to a piston or the like, which can move into and out of the fuel solution in response to a demand for hydrogen. Alternatively, the supported catalyst can be placed in a separate chamber and the flow rate of the fuel solution into the chamber can be controlled by means of valves and appropriate regulators. In a homogeneous catalyst, such as an acid solution, control of hydrogen generation is achieved by adjusting the flow rate of the borohydride fuel solution or catalyst solution, or both. Preferably, a mixing chamber is used in which the two solutions are injected or pumped into the chamber and they are mixed to cause a hydrolysis reaction.

In other embodiments, acid salts of polyhedral boron hydrides, such as hydronium salts whose cations are H ⁺ and ammonium salts whose cations are NH ₄ ⁺ , are used as a combination of fuel components and promoters for hydrogen generation. can do. Suitable promoter _{component, H 2 B 12 H 12,} H 2 B 10 H 10, there is _{(NH 4) 2 B 12 H} 12 and _{(NH 4) 2 B 10 H} 10. In such a system, no additional catalyst system is required, but it may be incorporated as needed to optimize the hydrogen generation rate. In this embodiment, the acidic polyhedral boron hydride salt (accelerator) is stored separately from the fuel mixture containing one or more boron hydrides and species that are optionally combined to produce hydrogen. . At least one of the accelerator or the fuel mixture is preferably an aqueous solution to facilitate mixing. However, one or both components (fuel blend and accelerator) may be stored as a dry powder to eliminate the need for stabilizers. In such cases, hydrogen generation requires a separate supply of water, and the drying and liquid components are added to the mixing chamber in a defined ratio using any method known to those skilled in the art. . This boron hydride species, concentration and mixing ratio is determined by the appropriate ⁺ IC / B ratio where the resulting borate falls between 0.2 and 0.4 or between 0.6 and 0.99. Is selected according to the present invention as described above. For this calculation only, this hydronium salt is considered a neutral boron hydride, for example, H ₂ B ₁₂ H ₁₂ is considered B ₁₂ H ₁₄ to determine the boron contribution. If hydrogen generation is required, this promoter is metered into the reactor and mixed with the boron hydride fuel mixture and any required water. This acidic polyhedral boron hydride salt thus acts as an accelerator that promotes the hydrogen evolution reaction, hydrolyzes to produce hydrogen, and in the fuel blend, boron atoms are added to the positive charge in the case of ammonium salts. Bring.

  It was found that the hydrogen gas formed in the hydrolysis reaction coeluted with the liquid borate product. Accordingly, in a preferred embodiment, a gas-liquid separator is used to separate hydrogen gas from the effluent. Furthermore, it is preferable to incorporate a small buffer tank in the system of the present invention to accommodate the immediate demand for hydrogen gas. In such an embodiment, this small buffer tank always contains a supply of hydrogen gas for the instantaneous demand for hydrogen. Once hydrogen is withdrawn from the buffer tank, the resulting pressure drop can be a trigger for the system to produce additional hydrogen gas so that a certain level of hydrogen gas is maintained therein.

  The hydrogen gas generated by the system of the present invention can be sent to a fuel cell or hydrogen consuming device for direct use. Alternatively, the hydrogen gas can be stored in a gas reservoir or buffer tank as described above for future use.

The fuel blend prepared according to the present invention is determined by two considerations. The first of these is the molar ratio of cationic charge ( ⁺ 1C) to boron atoms discussed herein. The second is the relative solubility of the individual salts utilized to form this mixture. Those skilled in the art have the maximum ratio and all components given the maximum ratios discussed herein and the relative solubility parameters of the individual salts (this information is readily available). It should be understood that it is possible to prepare a fuel solution that is soluble in an aqueous medium. Such calculations are illustrated by the following examples, which are for purposes of illustration and are not intended to limit the scope of the invention.

Example 1
General Procedure for Generating Hydrogen from Fuel Blends A general description of the hydrogen generation test is described using sodium borohydride, decaborane, sodium hydroxide and water in the fuel blend as a sample system. The fuel blend is made in open air. Water and stabilizing sodium hydroxide are first mixed, followed by the addition of decaborane, followed by the appropriate amount of sodium borohydride to give the desired ratio.

  A Parr reactor placed on a hot plate is used to catalytically drain the fuel blend. This reactor incorporates two thermocouples that operate continuously during operation, one measuring the temperature of the fuel solution and the other measuring the temperature of the headspace near the top of the reactor. The second thermocouple controls a cooling loop that circulates through the reactor, which is activated when the second thermocouple records a threshold temperature of 95 ° C. In practice, however, the reaction temperature rarely exceeds 90 ° C. even with a hot plate. The pressure sensor continuously measures the internal pressure. The reactor is first charged with six pieces of ruthenium-coated nickel catalyst (each piece weighing between 0.095 and 0.105 g). Approximately 10 grams of fuel blend (this weight was accurately known for each run) is injected through the inlet port and the port is sealed. The heat plate is then switched on. When this pressure stops increasing at a significant rate, the hot plate is switched off and the reactor is allowed to cool to room temperature. When the average gas temperature at the top of the reactor matches the average temperature of the reaction solution, data acquisition is stopped and the final pressure is measured. The final pressure and temperature along with the reactor volume can be used to calculate the molar yield of hydrogen gas. The molar yield is then compared to the expected yield from the amount and concentration of fuel to determine the percent yield.

  Pyrolysis is carried out in the same way as catalytic effluent, but the Parr reactor is not filled with catalyst and only heat from the hot plate causes hydrolysis of the blend.

(Example 2)
7.0 wt% hydrogen, ⁺ IC / B ratio = 0.8
The following were mixed according to the procedure of Example 1 to obtain 100 g of fuel blend having a sodium to boron ratio of 0.8 and capable of supplying 7.0 wt% H ₂ : borohydride Sodium 27.16 g; sodium hydroxide 3 g; decaborane (14) 3.34 g and water 66.5 g.
According to formula (1), 1 mole of sodium borohydride yields 4 moles of hydrogen.
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂ (1)
And according to formula (2), 1 mole of decaborane (14) yields 22 moles of hydrogen.
B ₁₀ H ₁₄ + 15H ₂ O → 5B ₂ O ₃ + 22H ₂ (2)

総水素収率は、５．７９＋１．２１＝７グラム又は７重量％である。 Hydrogen storage capacity of this blend, then calculates the total number of moles of produced H _2, it is determined by dividing by the initial weight of the blend.

The total hydrogen yield is 5.79 + 1.21 = 7 grams or 7% by weight.

したがって、このブレンドは０．８のＮａ：Ｂモル比を有する。 ⁺ IC: B ratio is calculated as follows.

This blend thus has a Na: B molar ratio of 0.8.

(Example 3)
6.8 wt% hydrogen, ⁺ IC / B ratio = 0.25
The following were mixed according to the procedure of Example 1 to obtain 100 g of fuel blend having a sodium to boron ratio of 0.25 and capable of supplying 6.8 wt% H ₂ : Triborohydride Sodium chloride 13.74 g; sodium dodecahydrododecaborate 13.74 g and water 76.09 g.
According to formula (3), 1 mole of sodium dodecahydrododecaborate yields 25 moles of hydrogen.
Na ₂ B ₁₂ H ₁₂ + 19H ₂ O → 2NaBO ₂ + 5B ₂ O ₃ + 25H ₂ (3)
And according to formula (4), 1 mole of sodium triborohydride yields 9 moles of hydrogen.
NaB ₃ H ₈ + 5H ₂ O → NaBO ₂ + B ₂ O ₃ + 9H ₂ (4)

総水素収率は、２．８７＋３．９３＝６．８グラム又は６．８重量％である。^＋ＩＣ：Ｂ比も以下の通り計算することができる。

したがって、このブレンドは０．２５のＮａ：Ｂモル比を有する。 Hydrogen storage capacity of this blend, then calculates the total number of moles of produced H _2, it is determined by dividing by the initial weight of the blend.

The total hydrogen yield is 2.87 + 3.93 = 6.8 grams or 6.8% by weight. ⁺ IC: B ratio can also be calculated as follows.

This blend therefore has a Na: B molar ratio of 0.25.

Example 4
5 wt% hydrogen, ⁺ IC / B ratio = 0.25
The following were mixed according to the procedure of Example 1 to obtain 100 g of fuel blend having a metal cation to boron ratio of 0.25 and capable of supplying 5.0 wt% H ₂ : 12.95 g potassium hydride; 6.76 g magnesium dodecahydrododecaborate and 80.03 g water.

According to formula (5), 1 mole of magnesium dodecahydrododecaborate yields 25 moles of hydrogen.
MgB ₁₂ H ₁₂ + 19H ₂ O → Mg (BO ₂ ) ₂ + 5B ₂ O ₃ + 25H ₂ (5)
According to formula (6), 1 mole of potassium triborohydride yields 9 moles of hydrogen.
KB ₃ H ₈ + 5H ₂ O → KBO ₂ + B ₂ O ₃ + 9H ₂ (6)

総水素収率は、２．０５＋２．９５＝５．０グラム又は５．０重量％である。^＋ＩＣ：Ｂ比も以下の通り計算することができる。

したがって、このブレンドは０．２５の^＋ＩＣ：Ｂモル比を有する。 Hydrogen storage capacity of this blend, then calculates the total number of moles of produced H _2, it is determined by dividing by the initial weight of the blend.

The total hydrogen yield is 2.05 + 2.95 = 5.0 grams or 5.0% by weight. ⁺ IC: B ratio can also be calculated as follows.

This blend therefore has a ⁺ IC: B molar ratio of 0.25.

(Examples 5 to 8)
The following fuel blend was prepared according to the procedure of Example 1 with similar calculations.

Example 9
5.6 wt% hydrogen, ⁺ IC / B ratio = 0.7
To illustrate the use of borohydride as a promoter, mixing sodium borohydride (20 mg), diammonium decahydrodecaborate (5 mg) and water (75 mg) together resulted in an immediate and intense hydrogen release. Happened with it. This mixture corresponds to a fuel blend having a + 1C to boron ratio of 0.7 and capable of supplying 5.6 wt% hydrogen. According to formula (1), 1 mole of sodium borohydride yields 4 moles of hydrogen.
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂ (1)
And according to formula (7), 1 mole of diammonium decahydrodecaborate yields 21 moles of hydrogen.
(NH ₄ ) ₂ B ₁₀ H ₁₀ + 16H ₂ O → 2 (NH ₄ ) ₂ BO ₂ + 4B ₂ O ₃ + 21H ₂ (7)

総水素収率は、４．２６＋１．４０＝５．６６ミリグラム又は５．６重量％である。^＋ＩＣ：Ｂ比も以下の通り計算することができる。

したがって、これは、０．７０のＮａ：Ｂモル比を有する燃料ブレンドに相当する。 Hydrogen storage capacity of this blend, then calculates the total number of moles of produced H _2, it is determined by dividing by the initial weight of the blend.

The total hydrogen yield is 4.26 + 1.40 = 5.66 milligrams or 5.6% by weight. ⁺ IC: B ratio can also be calculated as follows.

This therefore corresponds to a fuel blend having a Na: B molar ratio of 0.70.

(Example 10)
7.4 wt% hydrogen, ⁺ IC / B ratio = 0.38
According to the procedure of Example 9, sodium borohydride (17 g), hydronium salt of B ₁₂ H ₁₂ ^-2 (11 g), sodium hydroxide (3 g) and water (70 g) were combined to generate hydrogen. . This mixture represents a fuel blend having a ⁺ IC to boron ratio of 0.38 and capable of supplying 7.4 wt% hydrogen. According to formula (1), 1 mole of sodium borohydride yields 4 moles of hydrogen.
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂ (1)
And according to formula (8), 1 mole of H ₂ B ₁₂ H ₁₂ yields 25 moles of hydrogen.
H ₂ B ₁₂ H ₁₂ + 18H ₂ O → 6B ₂ O ₃ + 25H ₂ (8)

総水素収率は、３．６２＋３．８５＝７．４７グラム又は７．４重量％である。^＋ＩＣ：Ｂ比も以下の通り計算することができる。

したがって、これは、０．３８のＮａ：Ｂモル比を有する燃料ブレンドに相当する。 Hydrogen storage capacity of this blend, then calculates the total number of moles of produced H _2, it is determined by dividing by the initial weight of the blend.

The total hydrogen yield is 3.62 + 3.85 = 7.47 grams or 7.4% by weight. ⁺ IC: B ratio can also be calculated as follows.

This therefore corresponds to a fuel blend having a Na: B molar ratio of 0.38.

Claims (39)

An aqueous or hydroalcoholic solution of a mixture of boron hydrides, or a hydrogen comprising a slurry comprising at least one boron hydride salt having a cation selected from the group consisting of alkali metals, alkaline earth metals and aluminum cations. An aqueous fuel for generators wherein the mixture of boron hydrides has a cationic charge ( ⁺ IC) to boron ratio of between 0.2 and 0.4 or between 0.6 and 0.99. fuel. The aqueous fuel of claim 1, wherein the mixture of boron hydrides has a cationic charge ( ⁺ IC) to boron ratio of between 0.2 and 0.3 or 0.7 and 0.8. The boron hydride is a borohydride salt (MBH ₄ ), a triborohydride salt (MB ₃ H ₈ ), decahydrodecaborate (M ₂ B ₁₀ H ₁₀ ), tridecahydrodecaborate ( MB ₁₀ H ₁₃ ), dodecahydrododecaborate (M ₂ B ₁₂ H ₁₂ ), octadecahydroicosaborate (M ₂ B ₂₀ H ₁₈ ) and decaborane (14) (B ₁₀ H ₁₄ ) (M is 2. The aqueous fuel according to claim 1, wherein the aqueous fuel is selected from the group consisting of: an alkali metal, an alkaline earth metal and an aluminum cation.   The aqueous fuel of claim 1, wherein the mixture comprises a borohydride salt having a cation selected from the group consisting of sodium, lithium and potassium cations.   The mixture further comprises a stabilizer for the borohydride salt in an aqueous medium, the stabilizer comprising a hydroxide selected from the group consisting of sodium, lithium and potassium hydroxide. 5. The aqueous fuel according to 4.   6. The aqueous fuel of claim 5, wherein the borohydride salt is sodium borohydride and the stabilizer is sodium hydroxide.   The boron hydride mixture includes a borohydride salt and decaborane, the fuel also includes a stabilizer for the borohydride salt in an aqueous medium, and the stabilizer is a hydroxide of sodium, lithium, and potassium. The aqueous fuel of claim 3, comprising a hydroxide selected from the group consisting of:   8. The aqueous fuel of claim 7, wherein the borohydride mixture comprises sodium borohydride and decaborane, and the stabilizer is sodium hydroxide.   The aqueous fuel of claim 3, wherein the boron hydride mixture comprises triborohydride salt and dodecahydrododecaborate.   The aqueous fuel according to claim 9, wherein the triborohydride salt is potassium triborohydride and the dodecahydrododecaborate is magnesium dodecahydrododecaborate.   The boron hydride mixture includes a borohydride salt and dodecahydrododecaborate, the fuel also includes a stabilizer for the borohydride salt in an aqueous medium, and the stabilizer includes sodium, lithium, and The aqueous fuel according to claim 3, comprising a hydroxide selected from the group consisting of potassium hydroxide.   The aqueous fuel of claim 11, wherein the borohydride salt is sodium borohydride, the dodecahydrododecaborate is sodium dodecahydrododecaborate, and the stabilizer is sodium hydroxide.   The boron hydride mixture is a borohydride salt and a triborohydride salt, and the fuel also includes a stabilizer for the borohydride salt in an aqueous medium, the stabilizer comprising sodium, lithium and potassium. The aqueous fuel according to claim 3, comprising a hydroxide selected from the group consisting of:   14. The aqueous fuel according to claim 13, wherein the borohydride salt is sodium borohydride, the triborohydride salt is sodium triborohydride, and the stabilizer is sodium hydroxide. An aqueous solution or aqueous alcohol solution of a mixture of boron hydrides, or an aqueous solution comprising a slurry comprising at least one boron hydride salt having a cation selected from the group consisting of alkali metals, alkaline earth metals and aluminum cations. An aqueous fuel having a cationic charge ( ⁺ IC) to boron ratio of between 0.2 and 0.4 or between 0.6 and 0.99; And a hydrogen gas generation method comprising contacting with a hydrogen generation catalyst selected from the group consisting of transition metals. 16. Hydrogen gas generation according to claim 15, wherein the mixture of boron hydrides has a cationic charge ( ⁺ IC) to boron ratio between 0.2 and 0.3 or between 0.7 and 0.8. Method. The boron hydride is a borohydride salt (MBH ₄ ), a triborohydride salt (MB ₃ H ₈ ), decahydrodecaborate (M ₂ B ₁₀ H ₁₀ ), tridecahydrodecaborate ( MB ₁₀ H ₁₃ ), dodecahydrododecaborate (M ₂ B ₁₂ H ₁₂ ), octadecahydroicosaborate (M ₂ B ₂₀ H ₁₈ ) and decaborane (14) (B ₁₀ H ₁₄ ) (M is The method for generating hydrogen gas according to claim 15, wherein the method is selected from the group consisting of: an alkali metal, an alkaline earth metal, and an aluminum cation.   The method for generating hydrogen gas according to claim 15, wherein the mixture includes a borohydride salt in which M is selected from the group consisting of sodium, lithium and potassium.   19. The method for generating hydrogen gas according to claim 18, wherein the mixture further includes a stabilizer for the borohydride salt in an aqueous medium, and the stabilizer includes hydroxides of sodium, lithium, and potassium.   The method for generating hydrogen gas according to claim 15, wherein the catalyst is an acid selected from the group consisting of hydrochloric acid, sulfuric acid and phosphoric acid.   The method for generating hydrogen gas according to claim 1, wherein the catalyst contains one or more transition metals selected from the metal group of nickel, cobalt, and iron.   The method for generating hydrogen gas according to claim 21, wherein the catalyst is ruthenium, cobalt, or a mixture thereof. (A) an aqueous solution or aqueous alcohol solution or slurry of a borohydride mixture comprising at least one boron hydride salt having a cation selected from the group consisting of alkali metals, alkaline earth metals and aluminum cations An aqueous fuel wherein the mixture of boron hydrides has a cationic charge ( ⁺ IC) to boron ratio of between 0.2 and 0.4 or between 0.6 and 0.99 ,
(B) a hydrogen generation catalyst selected from the group consisting of acids and transition metals; and (c) a hydrogen generation system comprising means for bringing the aqueous fuel into contact with the catalyst and thereby generating hydrogen. 24. Hydrogen gas generation according to claim 23, wherein the mixture of boron hydrides has a cationic charge ( ⁺ IC) to boron ratio between 0.2 and 0.3 or between 0.7 and 0.8. Method. The boron hydride is a borohydride salt (MBH ₄ ), a triborohydride salt (MB ₃ H ₈ ), decahydrodecaborate (M ₂ B ₁₀ H ₁₀ ), tridecahydrodecaborate ( MB ₁₀ H ₁₃ ), dodecahydrododecaborate (M ₂ B ₁₂ H ₁₂ ), octadecahydroicosaborate (M ₂ B ₂₀ H ₁₈ ) and decaborane (14) (B ₁₀ H ₁₄ ) (M is 24. The hydrogen generation system according to claim 23, wherein the hydrogen generation system is selected from the group consisting of: an alkali metal, an alkaline earth metal and an aluminum cation.   24. The hydrogen generation system of claim 23, wherein the mixture comprises a borohydride salt having a cation selected from the group consisting of sodium, lithium and potassium cations.   The hydrogen generation system according to claim 23, wherein the hydrogen generation catalyst is an acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid, and the acid and the aqueous fuel are stored in separate containers.   The hydrogen generating catalyst comprises a substrate having transition metal molecules bound thereto, confined therein and / or coated thereon, wherein the means for contacting comprises the catalyst retention system. 24. The hydrogen generation system according to claim 23, wherein the hydrogen generation system is provided so that the catalyst can be moved in and out of contact with the aqueous fuel.   The hydrogen generation system according to claim 23, further comprising a gas-liquid separator for separating hydrogen from the effluent.   24. The hydrogen generation system of claim 23, wherein at least a portion of the water in the aqueous fuel is obtained from a reaction product of a hydrogen consuming device, and the device is operably coupled to the system.   31. The hydrogen generation system of claim 30, wherein the hydrogen consuming device is selected from the group consisting of a fuel cell, a combustion engine, a gas turbine, and combinations thereof. (A) a fuel blend comprising at least one boron hydride salt having a cation selected from the group consisting of alkali metals, alkaline earth metals and aluminum cations;
(B) a promoter comprising an acidic polyhedral boron hydride salt selected from the group consisting of hydronium salts and ammonium salts of polyhedral boron hydrides, wherein the mixture of boron hydride and promoter is 0.2 and 0 A promoter having a cationic charge ( ⁺ IC) to boron ratio between .4 or between 0.6 and 0.99; and (c) contacting the fuel blend and water with the promoter, thereby generating hydrogen. A hydrogen generation system including means. 33. The mixture of claim 32, wherein the mixture of boron hydride and promoter has a cationic charge ( ⁺ IC) to boron ratio between 0.2 and 0.3 or between 0.7 and 0.8. Hydrogen gas generation method. The boron hydride is a borohydride salt (MBH ₄ ), a triborohydride salt (MB ₃ H ₈ ), decahydrodecaborate (M ₂ B ₁₀ H ₁₀ ), tridecahydrodecaborate ( MB ₁₀ H ₁₃ ), dodecahydrododecaborate (M ₂ B ₁₂ H ₁₂ ), octadecahydroicosaborate (M ₂ B ₂₀ H ₁₈ ) and decaborane (14) (B ₁₀ H ₁₄ ) (M is 36. The hydrogen generation system of claim 35, selected from the group consisting of: selected from the group consisting of alkali metals, alkaline earth metals and aluminum cations. The promoter is _H 2 _{B 12 H} 12, hydrogen generating system according to claim 32. The hydrogen generation system of claim 32, wherein the promoter is (NH ₄ ) ₂ B ₁₀ H ₁₀ .   33. The hydrogen generation system of claim 32, wherein the mixture comprises a borohydride salt whose cation is selected from the group consisting of sodium, lithium and potassium.   33. The hydrogen generation system of claim 32, wherein at least a portion of the water is obtained from a reaction product of a hydrogen consuming device, and the device is operably coupled to the system.   40. The hydrogen generation system of claim 38, wherein the hydrogen consuming device is selected from the group consisting of a fuel cell, a combustion engine, a gas turbine, and combinations thereof.