초록 ▼

NOx emissions are reduced in the combustion of fuels by carrying out the combustion in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a fuel-lean zone. In accordance with another aspect of the present invention, SOx emissions are reduced in th

NOx emissions are reduced in the combustion of fuels by carrying out the combustion in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a fuel-lean zone. In accordance with another aspect of the present invention, SOx emissions are reduced in the burning of a normally solid fuel, containing significant amounts of SOx precursors, by adding a sulfur scavenger to the fuel and thereafter burning the fuel in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a last fuel-lean zone, and carrying out the combustion of the fuel in at least four combustion zones.

대표청구항 ▼

A method of burning a fuel, containing significant amounts of NOx precursors, comprising: (a) passing said fuel through at least four serially connected combustion zones in open communication with one another, including, at least three fuel-rich zones and a last fuel-lean zone; (b) adding a first vo

A method of burning a fuel, containing significant amounts of NOx precursors, comprising: (a) passing said fuel through at least four serially connected combustion zones in open communication with one another, including, at least three fuel-rich zones and a last fuel-lean zone; (b) adding a first volume of combustion-supporting material adjacent the upstream end of the first of said fuel-rich zones and intimately mixing the thus added first volume of combustion-supporting material with all of said fuel adjacent said upstream end of said first of said fuel-rich zones; (c) adding an additional volume of combustion-supporting material adjacent the upstream end of each of the remaining fuel-rich zones and intimately mixing the thus added additional volume of combustion-supporting material with effluent from the immediately preceeding fuel-rich zone adjacent said upstream end of each of said remaining fuel-rich zones; (d) the total combustion-supporting material thus added to the upstream ends of said first fuel-rich zone and said remaining fuel-rich zones, together with said fuel, resulting in a fuel/combustion-supporting material equivalence ratio greater than 1.0; (e) adding a still further volume of combustion-supporting material adjacent the upstream end of said fuel-lean zone and intimately mixing the thus added still further volume of combustion-supporting material with effluent from the last of said fuel-rich zones adjacent said upstream end of said fuel-lean zone; (f) the total combustion-supporting material thus added to the upstream ends of said first fuel-rich zone, said remaining fuel-rich zones and said fuel-lean zone, together with said fuel, resulting in a fuel/combustion-supporting material equivalence ratio less than 1.0; (g) providing an outlet from each combustion zone of substantially less cross-sectional area than the cross-sectional area of the beginning of the next succeeding combustion zone and abruptly terminating more fuel-rich combustion adjacent the downstream end of each of a preceeding one of said combustion zones and initiating less fuel-rich combustion adjacent the upstream end of each of an immediately succeeding one of said combustion zones, at least in part, by thus adding combustion-supporting material to the effluent of said preceeding one of said combustion zones as a plurality of radial jets toward the center of said combustion zone, whereby at least four clearly defined combustion zones are formed; and (h) burning said fuel in the presence of said combustion-supporting material in a serial manner in said at least four combustion zones.