Patent ID: 6910432

Claim:
A method for combusting a fuel in a cyclone combustor having a burner in communication with a barrel having a longitudinal axis, a burner end adjacent the burner, and a throat end opposite the burner end, comprising the steps of: feeding a stream of the fuel into the barrel of the cyclone combustor at the burner end of the cyclone combustor; feeding at least one stream of a first oxidant having a first oxygen concentration of about 21 vol. % into the barrel of the cyclone combustor at a first flowrate, the at least one stream of the first oxidant comprising at least one predominant stream of the first oxidant; feeding at least one stream of a second oxidant having a second oxygen concentration greater than the first oxygen concentration into the barrel of the cyclone combustor at a second flowrate and in a selective manner, whereby a portion of the first oxidant in the barrel of the cyclone combustor combines with at least a portion of the second oxidant in the barrel of the cyclone combustor, thereby forming a combined oxidant having a combined oxygen concentration greater than the first oxygen concentration and less than the second oxygen concentration, and at least a portion of the first oxidant from the at least one predominant stream of the first oxidant in the barrel of the cyclone combustor continues having the first oxygen concentration; and combusting at least a portion of the fuel in the barrel of the cyclone combustor with at least a portion of the combined oxidant in the barrel of the cyclone combustor.