Slow Cooking Heating Formula

Abstract

Chemical heating using a first reactant, a second reactant and a complexing agent adapted to complex reversibly with the first reactant and, thereby moderate the reaction between the first and second reactants. The heating formula is particularly well suited for heaters that are used to heat materials having relatively high viscosities.

1 . A heating formula for a chemical heater, the formula comprising:
 a first reactant;   a second reactant; and   a complexing agent that complexes reversibly with at least a portion of the first reactant so as to progressively release the complexed first reactant over time as a concentration of uncomplexed first reactant decreases during an exothermic reaction with the second reactant.   
     
     
         2 . The heating formula of  claim 1 , wherein:
 the first reactant is an oxidizing agent;   the second reactant is an alcohol fuel; and   the complexing agent complexes reversibly with at least a portion of the fuel so as to progressively release complexed fuel over time as a concentration of uncomplexed fuel decreases during the exothermic reaction with the oxidizing agent.   
     
     
         3 . The heating formula of  claim 1 , wherein:
 the first reactant is an alcohol fuel;   the second reactant is an oxidizing agent; and   the complexing agent complexes reversibly with at least a portion of the oxidizing agent so as to progressively release complexed oxidizing agent over time as a concentration of uncomplexed oxidizing agent decreases during the exothermic reaction with the fuel.   
     
     
         4 . The heating formula of  claim 2  wherein the fuel comprises a polyol. 
     
     
         5 . The heating formula of  claim 4  wherein the fuel comprises aqueous glycerol. 
     
     
         6 . The heating formula of  claim 2  wherein the complexing agent comprises boric acid or a borate. 
     
     
         7 . The heating formula of  claim 6  wherein the complexing agent comprises borax. 
     
     
         8 . The heating formula of  claim 2  wherein the complexing agent is selected from the group consisting of carbonate, nitrate, silicate and sulfate. 
     
     
         9 . The heating formula of  claim 3  wherein the complexing agent comprises a chelating agent. 
     
     
         10 . The heating formula of  claim 9  wherein the complexing agent comprises ethylenediaminetetraacetic acid (EDTA). 
     
     
         11 . The heating formula of  claim 2  wherein a ratio of complexing agent to fuel is between 1:20 and 1:5. 
     
     
         12 . The heating formula of  claim 2  wherein a ratio of complexing agent to fuel is between 1:100 and 1:1. 
     
     
         13 . The heating formula of  claim 2  wherein the oxidizing agent comprises an alkali metal permanganate. 
     
     
         14 . The heating formula of  claim 13  wherein the oxidizing agent comprises potassium permanganate. 
     
     
         15 . The heating formula of  claim 2  wherein the fuel and the complexing agent comprise an aqueous solution. 
     
     
         16 . The heating formula of  claim 2  wherein the fuel concentration is between 24 wt. % and 84 wt. %. 
     
     
         17 . The heating formula of  claim 2  wherein the fuel concentration is between 34 wt. % and 44 wt. %. 
     
     
         18 . A single-use chemical heater comprising:
 a disposable container comprising a first compartment and a second compartment;   a first reactant disposed in the first compartment;   a second reactant disposed in the second compartment;   a separator disposed between the first compartment and the second compartment, wherein the separator is compromisable to provide fluid communication between the first compartment and the second compartment, wherein the fluid communication initiates an exothermic chemical reaction between the first reactant and the second reactant within the container; and   disposed in at least one of the first compartment and the second compartment, a complexing agent that reversibly complexes with the first reactant.   
     
     
         19 . The heater of  claim 18 , wherein:
 the first reactant is an oxidizing agent;   the second reactant is an alcohol fuel; and   the complexing agent complexes reversibly with at least a portion of the fuel so as to progressively release complexed fuel over time as a concentration of uncomplexed fuel decreases during the exothermic reaction with the oxidizing agent.   
     
     
         20 . The heater of  claim 18 , wherein:
 the first reactant is an alcohol fuel;   the second reactant is an oxidizing agent; and   the complexing agent complexes reversibly with at least a portion of the oxidizing agent so as to progressively release complexed oxidizing agent over time as a concentration of uncomplexed oxidizing agent decreases during the exothermic reaction with the fuel.   
     
     
         21 . The heater of  claim 19  wherein the first compartment contains aqueous polyol fuel, a portion of which is complexed with a borax fuel-complexing agent. 
     
     
         22 . The heater of  claim 21  wherein the aqueous polyol fuel comprises glycerol. 
     
     
         23 . The heater of  claim 19  wherein a ratio of complexing agent to fuel is between 1:20 and 1:5. 
     
     
         24 . The heater of  claim 19  wherein a ratio of complexing agent to fuel is between 1:100 and 1:1. 
     
     
         25 . The heater of  claim 19  wherein the fuel concentration is between 34 wt. % and 44 wt. %. 
     
     
         26 . The heater of  claim 19  wherein the fuel concentration is between 24 wt. % and 84 wt. %. 
     
     
         27 . The heater of  claim 19  wherein the fuel-complexing agent comprises boric acid or borate. 
     
     
         28 . The heater of  claim 27  wherein the fuel-complexing agent comprises borax. 
     
     
         29 . The heater of  claim 22  wherein the fuel-complexing agent is selected from the group consisting of carbonate, nitrate, silicate and sulfate. 
     
     
         30 . The heater of  claim 20  wherein the complexing agent comprises a chelating agent. 
     
     
         31 . The heater of  claim 20  wherein the complexing agent comprises ethylenediaminetetraacetic acid (EDTA). 
     
     
         32 . The heater of  claim 19  wherein the oxidizing agent comprises sodium silicate-coated potassium permanganate. 
     
     
         33 . A method of moderating a rate of heat generation from a single-use chemical heater operable by exothermic chemical reaction of a first reactant and a second reactant, the method comprising:
 including in the exothermic chemical reaction a complexing agent that complexes reversibly with at least a portion of the first reactant so as to release portions of the first reactant to react with the second reactant over time as a concentration of uncomplexed first reactant decreases during the reaction.   
     
     
         34 . The method of  claim 33  wherein the first reactant is a fuel and the second reactant is an oxidizing agent, wherein the complexing agent complexes reversibly with at least a portion of the fuel so as to release portions of the fuel to react with the oxidizer over time as a concentration of uncomplexed fuel decreases during the reaction. 
     
     
         35 . The method of  claim 33  wherein the first reactant is an oxidizing agent and the second reactant is a fuel, wherein the complexing agent complexes reversibly with at least a portion of the oxidizing agent so as to release portions of the oxidizing agent to react with the fuel over time as a concentration of uncomplexed oxidizing agent decreases during the reaction. 
     
     
         36 . The method of  claim 34  wherein the complexing agent comprises boric acid or a borate. 
     
     
         37 . The method of  claim 34  wherein the fuel is a polyhydroxol compound and the complexing agent is borax. 
     
     
         38 . The method of  claim 34  wherein the complexing agent is selected from the group consisting of carbonate, nitrate, silicate and sulfate. 
     
     
         39 . The method of  claim 34  wherein the fuel is aqueous glycerol. 
     
     
         40 . The method of  claim 34  wherein the fuel concentration is between 34 wt. % and 44 wt. %. 
     
     
         41 . The method of  claim 34  wherein the fuel concentration is between 24 wt. % and 84 wt. %. 
     
     
         42 . The method of  claim 34  wherein the ratio of complexing agent to fuel is between 1:20 and 1:5. 
     
     
         43 . The method of  claim 34  wherein the oxidizing agent is potassium permanganate. 
     
     
         44 . The heating formula of  claim 3  wherein the fuel comprises a polyol. 
     
     
         45 . The heating formula of  claim 3  wherein the oxidizing agent comprises an alkali metal permanganate. 
     
     
         46 . The heating formula of  claim 3  wherein the fuel and the complexing agent comprise an aqueous solution.