Process for operating a coal-fired utility boiler

Abstract

A process for operating a coal-fired utility boiler. The process has the steps of (a) providing coal and one or more additives in proximity to one or more burners in the boiler; (b) providing air to the boiler; and (c) burning the coal and the one or more additives in the boiler to generate heat and an exhaust gas. Also disclosed are a burner and a coal-fired boiler.

1 . A process for operating a coal-fired utility boiler, comprising:
 a) providing coal and one or more additives in proximity to one or more burners in the boiler;   b) providing air to the boiler; and   c) burning the coal and the one or more additives in the boiler to generate heat and an exhaust gas.   
     
     
         2 . The process of  claim 1 , wherein the one or more additives are provided directly to one or more flames produced by the one or more burners. 
     
     
         3 . The process of  claim 2 , wherein one or more burners form one or more internal recirculation zones when lit into which the one or more additives are directed. 
     
     
         4 . The process of  claim 2 , wherein the one or more additives are provided by transmission through one or more hollow lances. 
     
     
         5 . The process of  claim 4 , wherein the one or more additives are provided by transmission through one or more hollow lances extending longitudinally within and through the one or more lances. 
     
     
         6 . The process of  claim 1 , wherein the one or more additives are provided by transmission through one or more lances. 
     
     
         7 . The process of  claim 1 , wherein the one or more additives are provided in a liquid form. 
     
     
         8 . The process of  claim 2 , wherein the one or more additives are provided in a liquid form. 
     
     
         9 . The process of  claim 1 , wherein the one or more additives are provided in a solid form. 
     
     
         10 . The process of  claim 1 , wherein the one or more additives provide one or more functionalities selected from the group consisting of (i) reduction in slag formation in the boiler, (ii) generation of oxygen in the boiler, (iii) reduction in acid formation in the boiler and the exhaust gas, (iv) reduced fouling in the boiler, (v) reduction in sulfur compound formation in the boiler and the exhaust gas, (vi) reduction in nitrogen compound formation in the boiler and the exhaust gas, (vii) reduction in particulate formation in the boiler and the exhaust gas, and (viii) capture of heavy metals in the boiler and the exhaust gas. 
     
     
         11 . The process of  claim 10 , wherein the one of more functionalities provided is (ii) generation of oxygen and (vii) reduction in particulate formation. 
     
     
         12 . The process of  claim 11 , wherein the one or more additives is one or more oxygen-generating agents selected from the group consisting of calcium hydroxide, calcium oxide, calcium carbonate, calcium carboxylate, calcium organometallic compounds, calcium sulfonate, iron hydroxides, iron oxides, iron carbonates, iron carboxylates, iron organometallic compounds, iron sulfonates, barium hydroxide, barium oxide, barium carbonate, barium carboxylate, barium organometallic compounds, and barium sulfonate. 
     
     
         13 . The process of  claim 10 , wherein the one or more additives is one or more slag control agents selected from the group consisting of magnesium hydroxide, magnesium oxide, magnesium carbonate, magnesium organometallic compounds, magnesium carboxylate, magnesium salicylate, magnesium napthenate, and magnesium sulfonate. 
     
     
         14 . The process of  claim 10 , wherein the one or more additives is one or more acid mitigation agents selected from the group consisting of magnesium oxide, magnesium hydroxide, magnesium carbonate, sodium bicarbonate carbonate, and calcium carbonate. 
     
     
         15 . The process of  claim 10 , wherein the one or more additives is one or more fouling prevention agents selected from the group consisting of magnesium oxide, magnesium hydroxide, magnesium carbonate, and sodium borate. 
     
     
         16 . The process of  claim 10 , wherein the one or more additives is one or more heavy metal capturing agents, wherein the one or more heavy metal capturing agents is one or more mercury capturing agents. 
     
     
         17 . The process of  claim 16 , wherein the one or more additives is one or more mercury capturing agents is selected from the group consisting of calcium sulfide, calcium polysulfide, and sodium sulfide. 
     
     
         18 . The process of  claim 1 , wherein the coal is provided via a first conduit, wherein the air is provided via a second conduit, wherein the one or more additives is provided via a third conduit, wherein the first conduit, the second conduit, and the third conduit direct the coal, the air, and the one or more additives proximal to one or more flames produced by the one or more burners. 
     
     
         19 . The process of  claim 18 , wherein the first conduit, the second conduit, and the third conduit direct the coal, the air, and the one or more additives directly to one or more flames produced by the one or more burners. 
     
     
         20 . A burner, comprising:
 a first conduit for transporting a fuel;   a second conduit for transporting air;   a third conduit for transporting an additive; and   an igniter adapted to initiate combustion of the fuel and the air,   wherein the first conduit, the second conduit, and the third conduit are longitudinally coextensive with each other, wherein the third conduit is positioned within the first conduit and the second conduit, wherein either the first conduit or the second conduit are positioned within the other, wherein the burner is adapted to maintain a continuous flame after initiation of combustion.   
     
     
         21 . The burner of  claim 20 , wherein the first conduit is positioned within the second conduit. 
     
     
         22 . The burner of  claim 20 , wherein the fuel is coal. 
     
     
         23 . The burner of  claim 20 , wherein the burner is adapted to form an internal recirculation zone after initiation of combustion. 
     
     
         24 . A coal-fired utility boiler, comprising:
 a furnace chamber adapted to combust coal and air, and   one or more burners positioned within the chamber,   wherein the one or more burners each include
 a first conduit for transporting the coal, 
 a second conduit for transporting air, 
 a third conduit for transporting an additive, and 
 an igniter adapted to initiate combustion of the fuel and the air, 
 wherein the first conduit, the second conduit, and the third conduit direct the coal, the air, and the additive proximal to the igniter, wherein the one or more burners each are adapted to maintain a continuous flame after initiation of combustion. 
   
     
     
         25 . The boiler of  claim 24 , wherein the first conduit, the second conduit, and the third conduit are longitudinally coextensive with each other, wherein the third conduit is positioned within the first conduit and the second conduit, wherein either the first conduit or the second conduit are positioned within the other.