Non-corrosive treatment to enhance pressurized and non-pressurized pulverized coal combustion

Abstract

Methods and compositions for inhibiting corrosion of metal surfaces in a furnace system are disclosed. In one aspect of the invention, pulverized coal is burned as fuel in the presence of a copper ion catalyst/combustion aid. Corrosion is inhibited in these systems by the use of a blend of primary aminoalcohol such as 2-aminoethanol, tertiary aminoalcohol such as triethanol amine, and boric acid or water soluble salt form of the acid.

What is claimed is:  
     
         1 . A method of inhibiting corrosion of metal surfaces in a furnace wherein coal is burned as a fuel, said method comprising burning said coal in the presence of a corrosion inhibiting treatment comprising an aminoalcohol.  
     
     
         2 . A method as recited in  claim 1  wherein said corrosion inhibiting treatment further comprises boric acid or water soluble salt of said boric acid.  
     
     
         3 . A method as recited in  claim 2  wherein said coal is pulverized and said treatment is applied in the form of an aqueous solution over said pulverized coal.  
     
     
         4 . A method as recited in  claim 2  wherein said treatment is sprayed in aqueous solution form into said furnace.  
     
     
         5 . A method as recited in  claim 2  wherein said aminoalcohol comprises a primary aminoalcohol having a primary amine functionality.  
     
     
         6 . A method as recited in  claim 5  wherein said aminoalcohol further comprises a tertiary aminoalcohol having tertiary amine functionality.  
     
     
         7 . A method as recited in  claim 5  wherein said aminoalcohol further comprises 2-aminoethanol.  
     
     
         8 . A method as recited in  claim 6  wherein said tertiary aminoalcohol is triethanolamine.  
     
     
         9 . A method as recited in  claim 8  wherein said coal is burned in the presence of copper.  
     
     
         10 . A method as recited in  claim 3  wherein said aqueous solution is sprayed over said pulverized coal in an amount of about 100 ml-1L of said aqueous solution per ton of said pulverized coal.  
     
     
         11 . A method as recited in  claim 10  wherein said aqueous solution is sprayed over said pulverized coal in an amount of about 300 ml-1L per ton of said pulverized coal.  
     
     
         12 . A method as recited in  claim 8  wherein said 2-aminoethanol, triethanolamine, and boric acid or salt thereof are present in combination in aqueous solution in an amount of about 1-10 wt %.  
     
     
         13 . A method as recited in  claim 12  further including sodium gluconate in said aqueous solution, said sodium gluconate being present in said aqueous solution in an amount of between about 1-10 wt %.  
     
     
         14 . In a method in which pulverized coal is burned as a fuel in a furnace in the present of copper to enhance the operation of the furnace, the improvement comprising also burning said coal in the presence of a corrosion inhibiting treatment, said treatment comprising 2-aminoethanol, triethanolamine and boric acid or water soluble thereof.  
     
     
         15 . A method as recited in  claim 14  wherein said copper and said corrosion inhibiting treatment are both sprayed onto said coal in the form of a single aqueous solution.  
     
     
         16 . A method as recited in  claim 14  wherein said corrosion inhibiting treatment further comprises gluconic acid or water soluble salt thereof.  
     
     
         17 . A method as recited in  claim 16  wherein said corrosion inhibiting treatment comprises sodium gluconate.  
     
     
         18 . A method as recited in  claim 17  wherein said 2-aminoethanol, triethanolamine and boric acid or salt thereof are present in combination in said aqueous solution in an amount of about 1-about 10 wt %, said sodium gluconate being present in said aqueous solution in an amount of about 1-15 wt % and wherein said copper is present in said aqueous solution as Cu ++  in an amount of about 1-20 wt %, and wherein about 100 ml-1L of said aqueous solution is sprayed onto said pulverized coal.  
     
     
         19 . Corrosion inhibiting composition comprising an aqueous solution comprising: 
 (a) 2-aminoethanol;    (b) triethanolamine; and    (c) boric acid or water soluble salt form.    
     
     
         20 . Corrosion inhibiting composition as recited in  claim 19  further comprising (d) sodium gluconate.  
     
     
         21 . Corrosion inhibiting composition as recited in  claim 20  further comprising (e) a copper ion source.  
     
     
         22 . Corrosion inhibiting composition as recited in  claim 21  wherein said copper ion source is copper sulfate pentahydrate or copper(II)-D Gluconate.  
     
     
         23 . Corrosion inhibiting composition as recited in  claim 21  wherein said (a), (b) and (c), in combination, are present in said aqueous solution in an amount of about 1-10 wt %, said (d) is present in said aqueous solution in an amount of about 1-15 wt % and wherein said copper ion source (e) is present in an amount sufficient to provide from about 1-20 wt % of Cu ++  ion in said aqueous solution.