Methods and apparatuses for removing mercury-containing material from emissions of combustion devices, and flue gas and flyash resulting therefrom

Abstract

A method of removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace includes feeding coal, which contains mercury or mercury-containing material, to a main furnace which produces flue gas. The method further includes feeding the coal to an auxiliary burner which produces a slipstream of flyash, feeding the slipstream of flyash from the auxiliary burner into the flue gas produced by the main furnace, and introducing a mercury-active oxidant to the coal being fed to the auxiliary burner, the combustion air fed to the auxiliary burner, and/or the flyash.

1 . A method of removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, the method comprising:
 feeding coal which contains mercury or mercury-containing material to a main furnace which produces flue gas;   feeding the coal to an auxiliary burner which produces a slipstream of flyash;   feeding the slipstream of flyash from the auxiliary burner into the flue gas produced by the main furnace; and   introducing a mercury-active oxidant to at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash, and selectively controlling the auxiliary burner to condition the flyash to a combustion stage associated with a desired activity in mercury oxidation.   
     
     
         2 . A method of removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, the method comprising:
 feeding coal which contains mercury or mercury-containing material to a main furnace which produces flue gas;   feeding the coal to an auxiliary burner which produces a slipstream of flyash;   feeding the slipstream of flyash from the auxiliary burner into the flue gas produced by the main furnace; and   introducing a mercury-active oxidant to at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash, and   wherein the mercury-active oxidant comprises at least one material selected from the group consisting of inorganic oxidants, organometallic oxidants, and organic oxidants, and further wherein the organic oxidants include hydrogen peroxide, organoperoxides, peroxyesters, peroxyacids, and organonitrates.   
     
     
         3 . A system for removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, comprising:
 a supply of coal which contains mercury or mercury-containing material;   a coal-burning main furnace configured to receive coal from the supply of coal and to produce flue gas from combustion of the coal;   an auxiliary burner configured to receive coal from the supply of coal, generate flyash, and direct the flyash to the flue gas of the main furnace; and   a treatment device configured to introduce a mercury-active oxidant into at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash, and   wherein the auxiliary burner is selectively controllable to condition the flyash to a combustion stage associated with a desired activity in mercury oxidation.   
     
     
         4 . A system for removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, comprising:
 a supply of coal which contains mercury or mercury-containing material;   a coal-burning main furnace configured to receive coal from the supply of coal and to produce flue gas from combustion of the coal;   an auxiliary burner configured to receive coal from the supply of coal, generate flyash, and direct the flyash to the flue gas of the main furnace; and   a treatment device configured to introduce a mercury-active oxidant into at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash,   wherein the mercury-active oxidant comprises at least one material selected from the group consisting of inorganic oxidants, organometallic oxidants, and organic oxidants, and   wherein the organic oxidants include hydrogen peroxide, organoperoxides, peroxyesters, peroxyacids, and organonitrates.   
     
     
         5 . A method of removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, the method comprising:
 feeding coal to an auxiliary burner which produces a slipstream of flyash;   generating a slipstream of flyash from the auxiliary burner;   feeding the slipstream of flyash into flue gas produced by the main furnace; and   introducing a mercury-active oxidant into at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash,   further comprising selectively controlling the auxiliary burner to condition the flyash to a combustion stage associated with a desired activity in mercury oxidation.   
     
     
         6 . A method of removing mercury or mercury-containing material from flue gas produced by a coal-burning main furnace, the method comprising:
 feeding coal to an auxiliary burner which produces a slipstream of flyash;   generating a slipstream of flyash from the auxiliary burner;   feeding the slipstream of flyash into flue gas produced by the main furnace; and   introducing a mercury-active oxidant into at least one of the coal being fed to the auxiliary burner, the combustion air being fed to the auxiliary burner, and the flyash,   wherein the mercury-active oxidant comprises at least one material selected from the group consisting of inorganic oxidants, organometallic oxidants, and organic oxidants, and   wherein the organic oxidants include hydrogen peroxide, organoperoxides, peroxyesters, peroxyacids, and organonitrates.