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.

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-1 L of said aqueous solution per ton of said pulverized coal. 
   
   
       11 . A method as recited in  claim 8  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 %. 
   
   
       12 . In a method in which pulverized coal is burned as a fuel in a furnace in the presence 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. 
   
   
       13 . A method as recited in  claim 12  wherein said copper and said corrosion inhibiting treatment are both sprayed onto said coal in the form of a single aqueous solution. 
   
   
       14 . A method as recited in  claim 12  wherein said corrosion inhibiting treatment further comprises gluconic acid or water soluble salt thereof. 
   
   
       15 . A method as recited in  claim 14  wherein said corrosion inhibiting treatment comprises sodium gluconate. 
   
   
       16 . A method as recited in  claim 15  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 -118 L of said aqueous solution is sprayed onto said pulverized coal. 
   
   
       17 . A method of inhibiting corrosion in a furnace in which pulverized coal is burned as fuel in the presence of a metallic combustion catalyst, the improvement comprising burning said coal in the presence of a corrosion inhibiting treatment, said corrosion inhibiting treatment comprising an aminoalcohol and boric acid. 
   
   
       18 . A method as recited in  claim 17  wherein said furnace comprises metal surfaces therein, said method further comprising forming a protective, corrosion inhibiting film on said metal surfaces by reaction of said corrosion inhibiting treatment and said metallic combustion catalyst. 
   
   
       19 . A method as recited in  claim 17  wherein said furnace comprises metal surfaces therein and said metallic combustion catalyst comprises copper, said corrosion inhibiting treatment comprising 2-aminoethanol, triethanolamine, and boric acid, said method further comprising forming a protective, corrosion inhibiting film on said metal surfaces by reaction of said corrosion inhibiting treatment and said copper combustion catalyst. 
   
   
       20 . A method as recited in  claim 19  wherein said corrosion inhibiting treatment further comprises sodium gluconate.