Hydrogen elimination and thermal energy generation in water-activated chemical heaters

Abstract

A hydrogen suppressing, flameless, heat generating chemical composition including magnesium, a hydrogen suppressor or eliminator, particulate carbon, an alloying metal selected from the group consisting of: iron, cobalt, nickel, zinc, aluminum and mixtures thereof, a metallic salt including a cation and an anion, wherein the anion is selected from the group consisting of silicate, carbonate, bicarbonate, phosphate, borate, perborate, percarbonate, perphosphate, persulfate, nitrate, nitrite, ferrate, permanganate, and stannate and combinations thereof, and water. The magnesium or magnesium-containing alloy, hydrogen suppressor or eliminator, particulate carbon, alloying metal, metallic salt and water are each present in a proportional amount to generate sufficient heat to heat water, medical supplies and/or consumable rations.

1 . A hydrogen suppressing, flameless, heat generating chemical composition comprising:
 magnesium;   a hydrogen suppressor or eliminator;   particulate carbon;   an alloying metal selected from the group consisting of: iron, cobalt, nickel, zinc, aluminum and mixtures thereof;   a metallic salt comprising a cation and an anion, wherein said anion is selected from the group consisting of silicate, carbonate, bicarbonate, phosphate, borate, perborate, percarbonate, perphosphate, persulfate, nitrate, nitrite, ferrate, permanganate, and stannate and combinations thereof; and,   water, wherein said magnesium or magnesium-containing alloy, hydrogen suppressor or eliminator, particulate carbon, alloying metal, metallic salt and water are each present in a proportional amount to generate sufficient heat to heat water, medical supplies and/or consumable rations.   
     
     
         2 . The hydrogen suppressing, flameless, heat generating chemical composition according to  claim 1 , further comprising at least one member selected from the group consisting of a hydrogen overvoltage suppressor, a flowing agent and a reaction activator. 
     
     
         3 . The hydrogen suppressing, flameless, heat generating composition according to  claim 1 , wherein the alloying metal is present in an amount from about 0.001 to about 10 percent by-weight 
     
     
         4 . The hydrogen suppressing, flameless, heat generating chemical composition according to  claim 1 , wherein said hydrogen suppressor comprises oxides of manganese and/or ruthenium. 
     
     
         5 . The hydrogen suppressing, flameless, heat generating chemical composition according to  claim 4 , wherein said oxide of manganese is γ-MnO 2  or β-MnO 2 . 
     
     
         6 . The hydrogen suppressing, flameless, heat generating chemical composition according to  claim 4 , wherein the oxide of manganese is present in an amount ranging from 0.5 to about 10 times the stoichiometric amount required for the magnesium and the oxide of manganese reaction with water to occur. 
     
     
         7 . The hydrogen suppressing, flameless, heat generating chemical composition according to  claim 2 , wherein the hydrogen overvoltage suppressor is a metal sulfide and the activator is an inorganic salt. 
     
     
         8 . The hydrogen suppressing, flameless, heat generating composition according to  claim 2 , wherein the reaction activator is selected from the group consisting of: alkali metal halides, magnesium halide salts, thermally and electrically conducting, high surface area synthetic graphite, conducting carbon, conducting graphite, carbon and mixtures thereof, and the reaction activator is present in an amount from about 0.001 to about 50 percent by-weight. 
     
     
         9 . The hydrogen suppressing, flameless, heat generating composition according to  claim 8 , wherein the reaction activator is mixed with milled magnesium-manganese dioxide mixtures prior to activating the heater reaction with water. 
     
     
         10 . The hydrogen suppressing, flameless, heat generating composition according to  claim 8 , wherein the reaction activator is the synthetic graphite, the synthetic graphite is Asbury 4827. 
     
     
         11 . The hydrogen suppressing, flameless, heat generating composition according to  claim 8 , wherein the reaction activator is the conducting carbon, the conducting carbon is Ketjenblack, Black Pearls® 2000, Black Pearls® 1300 or Asbury TC 307. 
     
     
         12 . The hydrogen suppressing, flameless, heat generating composition according to  claim 1 , wherein said cation is selected from the group consisting of an alkaline metal and an alkali metal. 
     
     
         13 . The hydrogen suppressing, flameless, heat generating composition according to  claim 1 , wherein said cation is selected from the group consisting of sodium, calcium, magnesium and potassium. 
     
     
         14 . The hydrogen suppressing, flameless, heat generating composition according to  claim 1 , wherein the metallic salt and water are added either sequentially or together. 
     
     
         15 . A heater device comprising the hydrogen suppressing, flameless, heat generating chemical composition according to  claim 1 . 
     
     
         16 . The heater device of  claim 15  wherein the hydrogen suppressing, flameless, heat generating chemical composition is enclosed within a bag, the bag comprising a plurality of compartments. 
     
     
         17 . The heater device of  claim 16  wherein the bag comprises a filter cloth, said filter cloth comprises a spunbond/melt blown/spunbond polypropylene media. 
     
     
         18 . The heater device of  claim 16  wherein the compartments are formed by a heat seal. 
     
     
         19 . The heater device of  claim 16  wherein the compartments are formed by a frame, the frame formed by at least one piece of a fluted and ribbed material, the frame bonded to the bag by an adhesive. 
     
     
         20 . The heater device of  claim 16  wherein the bag comprises at least one drop of a hydrophilizing fluid on at least one side of the bag. 
     
     
         21 . A meal, ready-to-eat package comprising the flameless heater device according to  claim 15 .