Method of operating a combusion installation and use of such a method for inhibiting vanadium corrosion

Abstract

A method of operating a thermal installation other than a gas turbine and use of such a method for inhibiting vanadic corrosion is disclosed herein. Embodiments of the invention relate to a method of operating a thermal installation comprising a combustion chamber fed with a fuel contaminated with vanadium, with sulfur and possibly with sodium. The combustion chamber is also fed with boron and with magnesium, in quantities such that the magnesium molar ratio m=MgO/V2O5 and the boron molar ratio b=B2O3/V2O5 satisfy the conditions (i) m≧2+b; (ii) m≦3+2b; (iii) b≧0.5 and (iv) b≦2, so that the combustion products comprise magnesium vanadate, mixed magnesium boron oxide and possibly sodium borate.

What is claimed is: 
     
         1 . A method of operating a combustion installation comprising feeding to the combustion installation a fuel contaminated with vanadium and feeding to a combustion chamber of the combustion installation one or more boron compounds and one or more magnesium compounds, in quantities such that the molar ratio of MgO equivalents added to the combustion chamber relative to the moles of V 2 O 5  formed in the combustion chamber from the vanadium in the fuel, is molar ratio m, and the molar ratio of B 2 O 3  equivalents added to the combustion chamber relative to the moles of V 2 O 5  formed in the combustion chamber from the vanadium in the fuel is molar ratio b, and wherein the molar ratios b and m satisfy the following conditions: (i) m≧2+b and (ii) b≧0.5. 
     
     
         2 . The method according to  claim 1 , wherein the molar ratios b and m satisfy the additional condition: m≦3+2b. 
     
     
         3 . The method according to  claim 2 , wherein the molar ratios b and m satisfy the additional conditions: (i) m≦5 and (ii) b≦1.5. 
     
     
         4 . The method according to  claim 1 , wherein at least some of the boron and magnesium fed to the combustion chamber is in the form of mixed magnesium boron oxide. 
     
     
         5 . The method according to  claim 4 , wherein the mixed magnesium boron oxide is in nanoscale form. 
     
     
         6 . The method according to  claim 1 , wherein at least some mixed magnesium-boron oxide is formed in the combustion chamber from at least one precursor introduced upstream of the combustion chamber. 
     
     
         7 . The method according to  claim 6 , wherein the mixed magnesium-boron oxide is in nanoscale form. 
     
     
         8 . The method according to  claim 1 , wherein the combustion installation is operated at a flue gas temperature of 300° C. to 1050° C. 
     
     
         9 . The method according to  claim 1 , wherein the combustion installation is operated at a pressure of 300 psig to 2650 psig. 
     
     
         10 . The method according to  claim 1 , wherein the combustion installation is operated at a flue gas temperature of 300° C. to 1050° C. and at a pressure of 300 psig to 2650 psig. 
     
     
         11 . The method according to  claim 1 , wherein the fuel fed to the combustion installation comprises sulfur and possibly sodium. 
     
     
         12 . The method according to  claim 1 , wherein the combustion installation is a steam boiler. 
     
     
         13 . The method according to  claim 1 , wherein the one or more boron compounds comprise at least one of B 2 O 3 , MgB 4 O 7 , Mg 3 B 2 O 6 , and Mg 2 B 2 O 5 , and the one or more magnesium compounds comprise at least one of MgO, MgB 4 O 7 , Mg 3 B 2 O 6 , and Mg 2 B 2 O 5 , and wherein the molar MgO equivalents and the molar B 2 O 3  equivalents are based on the moles of at least one of MgO, B 2 O 3 , MgB 4 O 7 , Mg 3 B 2 O 6 , and Mg 2 B 2 O 5  added to the combustion installation. 
     
     
         14 . The method according to  claim 1 , wherein the one or more boron compounds comprise at least one of B 2 O 3 , Mg 3 B 2 O 6 , and Mg 2 B 2 O 5 , and the one or more magnesium compounds comprise at least one of MgO, Mg 3 B 2 O 6 , and Mg 2 B 2 O 5 , and wherein the molar MgO equivalents and the molar B 2 O 3  equivalents are based on the moles of at least one of MgO, B 2 O 3 , Mg 3 B 2 O 6 , and Mg 2 B 2 O 5  added to the combustion installation. 
     
     
         15 . The method according to  claim 1 , wherein the one or more boron compounds comprise B 2 O 3 , and the one or more magnesium compounds comprise MgO, and wherein b is the molar ratio B 2 O 3 /V 2 O 5  and wherein m is the molar ratio MgO/V 2 O 5 . 
     
     
         16 . The method according to  claim 13 , wherein molar ratios b and m satisfy the additional condition: m≦3+2b. 
     
     
         17 . The method according to  claim 13 , wherein molar ratios b and m satisfy the additional conditions: (i) m≦5 and (ii) b≦1.5. 
     
     
         18 . The method according to  claim 15 , wherein at least one of the B 2 O 3  and the MgO are in nanoscale form.