Method of producing fuel dispersion for a fuel cell

Abstract

A method of producing a fuel or concentrate thereof for a fuel cell. The method comprises providing a solution of at least one hydroxide ion providing compound in a liquid medium and combining and mixing one or more hydride compounds with this solution to provide a colloidal dispersion of the hydride compound(s) in the alkaline medium. This Abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

1 . A method of producing a fuel or fuel concentrate for a fuel cell, which method comprises: 
 (a) providing a solution of one or more hydroxide ion providing compounds in a liquid medium; and    (b) combining and mixing one or more hydride compounds with the solution of (a) to provide a colloidal dispersion of the one or more hydride compounds in an alkaline medium.    
   
   
       2 . The method of  claim 1 , wherein the solution of (a) has a hydroxide ion concentration of at least about 0.2 mole per liter.  
   
   
       3 . The method of  claim 1 , wherein the solution of (a) has a hydroxide ion concentration of at least about 2 moles per liter.  
   
   
       4 . The method of  claim 2 , wherein the solution of (a) has a hydroxide ion concentration of up to about 14 moles per liter.  
   
   
       5 . The method of  claim 1 , wherein the solution of (a) has a temperature of not higher than about 70° C.  
   
   
       6 . The method of  claim 1 , wherein the one or more hydride compounds are employed in an amount which affords a total concentration of at least about 2 moles per liter of colloidal dispersion.  
   
   
       7 . The method of  claim 2 , wherein the one or more hydride compounds are employed in an amount which affords a total concentration of at least about 5 moles per liter of colloidal dispersion.  
   
   
       8 . The method of  claim 5 , wherein the one or more hydride compounds are employed in an amount which affords a total concentration of at least about 7 moles per liter of colloidal dispersion.  
   
   
       9 . The method of  claim 1 , wherein at least two hydride compounds are employed.  
   
   
       10 . The method of  claim 9 , wherein the at least two hydride compounds are added substantially successively to the solution of (a).  
   
   
       11 . The method of  claim 10 , wherein a solubility of a first hydride compound of the at least two hydride compounds in the solution of (a) is higher than a solubility of a second hydride compound of the at least two hydride compounds and wherein at least a part of the first hydride compound is added to the solution of (a) before the second hydride compound is added thereto.  
   
   
       12 . The method of  claim 1 , wherein the one or more hydride compounds are capable of at least one of undergoing anodic oxidation in a liquid fuel cell and undergoing decomposition with generation of hydrogen gas under conditions which promote a hydrolysis thereof.  
   
   
       13 . The method of  claim 1 , wherein the one or more hydride compounds are selected from ammonium, alkali and alkaline earth metal hydrides, borohydrides and aluminum hydrides.  
   
   
       14 . The method of  claim 1 , wherein the one or more hydride compounds are selected from NaBH 4 , KBH 4 , LiBH 4 , NH 4 BH 4 , Be(BH 4 ) 2 , Ca(BH 4 ) 2 , Mg(BH 4 ) 2 , Zn(BH 4 ) 2 , Al(BH 4 ) 3 , a polyborohydride, (CH 3 ) 2 NHBH 3 , NaCNBH 3 , LiH, NaH, KH, CaH 2 , BeH 2 , MgH 2 , NaAlH 4 , LiAlH 4  and KAlH 4 .  
   
   
       15 . The method of  claim 1 , wherein the one or more hydride compounds comprise at least one of NaBH 4 , KBH 4 , LiBH 4 , NH 4 BH 4  and a polyborohydride of formula MB 3 H 8 , M 2 B 10 H 10 , MB 10 H 13 , M 2 B 12 H 12  or M 2 B 20 H 18  wherein M=Li, Na, K, NH 4 , Be 1/2 , Ca 1/2 , Mg 1/2 , Zn 1/2  or Al 1/3 .  
   
   
       16 . The method of  claim 15 , wherein the one or more hydride compounds comprise at least one of NaBH 4  and KBH 4 .  
   
   
       17 . The method of  claim 1 , wherein the one or more hydroxide ion providing compounds are selected from hydroxides of alkali and alkaline earth metals, Zn and Al and from ammonium hydroxide.  
   
   
       18 . The method of  claim 17 , wherein the one or more hydroxide ion providing compounds comprise at least one of LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH) 2 , Mg(OH) 2 , Ba(OH) 2 , Zn(OH) 2 , Al(OH) 3  and NH 4 OH.  
   
   
       19 . The method of  claim 18 , wherein the one or more hydroxide ion providing compounds comprise at least one of NaOH and KOH.  
   
   
       20 . The method of  claim 1 , wherein the solution of (a) comprises water.  
   
   
       21 . The method of  claim 20 , wherein the colloidal dispersion comprises water and at least one water-soluble substance which is capable of stabilizing the colloidal dispersion, the at least one water-soluble substance being at least one of present in the solution of (a) and being added to the solution of (a) at least one of after and together with the one or more hydride compounds.  
   
   
       22 . The method of  claim 21 , wherein the at least one water-soluble substance is selected from one or more of (cyclo)aliphatic alcohols having up to about 6 carbon atoms and up to about 6 hydroxy groups, C 2-4  alkylene glycols, di(C 2-4  alkylene glycols), poly(C 2-4  alkylene glycols), mono-C 1-4 -alkyl ethers of C24 alkylene glycols, di(C 2-4  alkylene glycols) and poly(C 2-4  alkylene glycols), di-C 1-4 -alkyl ethers of C 2-4  alkylene glycols, di(C 2-4  alkylene glycols) and poly(C 2-4  alkylene glycols), ethylene oxide/propylene oxide block copolymers, ethoxylated aliphatic polyols, propoxylated aliphatic polyols, ethoxylated and propoxylated aliphatic polyols, aliphatic ethers having up to about 6 carbon atoms, aliphatic ketones having up to about 6 carbon atoms, aliphatic aldehydes having up to about 6 carbon atoms, C 1-4 -alkyl esters of C 1-4  alkanoic (aliphatic) acids and primary, secondary and tertiary aliphatic amines having a total of up to about 10 carbon atoms.  
   
   
       23 . The method of  claim 21 , wherein the at least one water-soluble substance is selected from one or more of methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, 1,2,4-butanetriol, trimethylolpropane, pentaerythritol, sorbitol, glycerol, acetone, methyl ethyl ketone, diethyl ketone, methyl acetate, ethyl acetate, dioxan, tetrahydrofuran, diglyme, triglyme, monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine and tripropanolamine.  
   
   
       24 . The method of  claim 21 , wherein the at least one water-soluble substance comprises at least one of a water-soluble polymer and a water-swellable polymer.  
   
   
       25 . The method of  claim 24 , wherein the polymer has an initial particle size of from about 0.02 to about 50 micron.  
   
   
       26 . The method of  claim 21 , wherein a weight ratio of water and the at least one water-soluble substance is from about 200:1 to about 2:1.  
   
   
       27 . A method of producing a fuel or fuel concentrate for a fuel cell, which method comprises: 
 (a) providing a solution of one or more hydroxide ion providing compounds in an aqueous medium, the solution having a concentration of hydroxide ions of at least about 0.2 mole per liter and being at a temperature of not higher than about 70° C.; and    (b) adding one or more metal hydride compounds to the solution of (a) and mixing the one or metal hydride compounds with the solution to provide a colloidal dispersion of the one or more metal hydride compounds in an alkaline aqueous medium;    the one or more hydride compounds being employed in an amount which results in a total concentration thereof in the fuel or fuel concentrate of at least about 2 moles per liter.    
   
   
       28 . The method of  claim 27 , wherein the solution of (a) has a hydroxide ion concentration of at least about 2 moles per liter.  
   
   
       29 . The method of  claim 28 , wherein the one or more metal hydride compounds are employed in a total amount of at least about 5 moles per liter of fuel or fuel concentrate.  
   
   
       30 . The method of  claim 29 , wherein the one or more metal hydride compounds comprise at least one of NaBH 4  and KBH 4 .  
   
   
       31 . The method of  claim 30 , wherein the one or more hydroxide ion providing compounds comprise at least one of NaOH and KOH.  
   
   
       32 . The method of  claim 30 , wherein the aqueous medium of (a) comprises water and at least one water-soluble substance selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, 1,2,4-butanetriol, trimethylolpropane, glycerol, pentaerythritol, sorbitol, acetone, methyl ethyl ketone, diethyl ketone, methyl acetate, ethyl acetate, dioxane, tetrahydrofuran, diglyme, triglyme, monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine and tripropanolamine.  
   
   
       33 . The method of  claim 32 , wherein a weight ratio of water and the at least one water-soluble substance is from about 200:1 to about 3:1.  
   
   
       34 . A method of producing a fuel of fuel concentrate for a fuel cell, which method comprises mixing one or more hydroxide ion providing compounds, one or more hydride compounds and one or more polar solvents in relative ratios which result in a colloidal dispersion of the one or more hydride compounds in an alkaline medium.  
   
   
       35 . The method of  claim 34 , wherein the one or more hydroxide ion providing compounds comprise at least one of an alkali or alkaline earth metal hydroxide, ammonium hydroxide, Zn(OH) 2  and Al(OH) 3 , the one or more hydride compounds comprise at least one of NaBH 4 , KBH 4 , LiBH 4 , NH 4 BH 4 , Be(BH 4 ) 2 , Ca(BH 4 ) 2 , Mg(BH 4 ) 2 , Zn(BH 4 ) 2 , Al(BH 4 ) 3 , and a polyborohydride, and the one or more polar solvents comprise water and at least one water-soluble substance selected from aliphatic alcohols having up to about 6 carbon atoms and up to about 6 hydroxy groups, C 2-4  alkylene glycols, di(C 2-4  alkylene glycols), poly(C 2-4  alkylene glycols), mono- and di-C 1-4 -alkyl ethers of C 2-4  alkylene glycols, di(C 2-4  alkylene glycols) and poly(C 2-4  alkylene glycols), ethylene oxide/propylene oxide block copolymers, ethoxylated aliphatic polyols, propoxylated aliphatic polyols, ethoxylated and propoxylated aliphatic polyols, aliphatic ethers having up to about 6 carbon atoms, aliphatic ketones having up to about 6 carbon atoms, aliphatic aldehydes having up to about 6 carbon atoms, C 1-4 -alkyl esters of C 1-4  alkanoic (aliphatic) acids and primary, secondary and tertiary aliphatic amines having a total of up to about 10 carbon atoms.  
   
   
       36 . The method of  claim 35 , wherein the one or more hydroxide ion providing compounds are employed in a total concentration of at least about 0.5 mole per liter of fuel or fuel concentrate and the one or more hydride compounds are employed in a total concentration of at least about 2 moles per liter of fuel or fuel concentrate.  
   
   
       37 . A fuel or fuel concentrate, obtainable by the method of  claim 34 .  
   
   
       38 . The fuel concentrate of  claim 37 , wherein the fuel concentrate has a Brookfield viscosity of at least about 2,000 cP.  
   
   
       39 . The fuel concentrate of  claim 38 , wherein the fuel concentrate has a density of at least about 1.20 g/cm 3 .  
   
   
       40 . A method of producing a fuel for a fuel cell from a fuel concentrate, wherein the method comprises diluting the fuel concentrate of  claim 37  with a polar solvent.  
   
   
       41 . The method of  claim 40 , wherein both the fuel concentrate and the polar solvent comprise water.  
   
   
       42 . The method of  claim 41 , wherein the fuel concentrate comprises water and at least one water-soluble substance selected from one or more of aliphatic alcohols having up to about 6 carbon atoms and up to about 6 hydroxy groups, C 2-4  alkylene glycols, di(C 2-4  alkylene glycols), poly(C 2-4  alkylene glycols), mono- and di-C 1-4 -alkyl ethers of C 2-4  alkylene glycols, di(C 2-4  alkylene glycols) and poly(C 2-4  alkylene glycols), ethylene oxide/propylene oxide block copolymers, ethoxylated aliphatic polyols, propoxylated aliphatic polyols, ethoxylated and propoxylated aliphatic polyols, aliphatic ethers having up to about 6 carbon atoms, aliphatic ketones having up to about 6 carbon atoms, aliphatic aldehydes having up to about 6 carbon atoms, C 1-4 -alkyl esters of C 1-4  alkanoic (aliphatic) acids and primary, secondary and tertiary aliphatic amines having up to about 10 carbon atoms.  
   
   
       43 . The method of  claim 42 , wherein the polar solvent comprises at least about 75% by weight of water.  
   
   
       44 . The method of  claim 41 , wherein the fuel concentrate has a hydroxide ion concentration of at least about 0.5 mole per liter and the polar solvent is added in an amount which results in a hydroxide ion concentration of the fuel of not more than about 90% of the hydroxide ion concentration of the fuel concentrate.  
   
   
       45 . The method of  claim 40 , wherein a weight ratio of the fuel concentrate and the polar solvent is from about 5:1 to about 1:5.  
   
   
       46 . The method of  claim 40 , wherein the fuel concentrate has a Brookfield viscosity of at least about 2,000 cP and the fuel has a Brookfield viscosity of not higher than about 1,000 cP.  
   
   
       47 . The method of  claim 40 , wherein the fuel concentrate has a density of at least about 1.20 g/cm 3 .  
   
   
       48 . The method of  claim 40 , wherein the fuel has a density of not higher than about 1.50 g/cm 3 .