Patent ID: 8172567

Claim:
A method for uniformly distributing heat within a furnace and for decreasing NO x in combustion products, said method comprising: a. adding a supplemental oxidant to an existing furnace that includes at least one existing burner having a burner outlet and utilizing air as a first oxidant for combustion with a fuel supplied to the at least one burner wherein the supplemental oxidant is introduced into the furnace through at least one lance that is spaced from the at least one existing burner; b. introducing supplemental oxidant from the at least one lance into the furnace for selectively providing additional oxidant for combustion of the fuel, wherein the supplemental oxidant issues from an outlet of the at least one lance and forms a supplemental-oxidant stream that has a longitudinal axis that is inclined toward a longitudinal axis of a flame that forms from combustion of the air and fuel that issue from the at least one existing burner; c. feeding the supplemental oxidant into the at least one lance, wherein the supplemental oxidant contains at least 85 weight % oxygen gas; d. impinging the supplemental oxidant stream upon the flame issuing from the at least one existing burner, wherein impingement of the at least 85 wt % oxygen gas in the supplemental oxidant occurs at an impingement point that is spaced outwardly from an outlet of the existing burner, wherein an oxygen content supplied by air introduced into the furnace through the at least one existing burner for combustion and an oxygen content contained in the supplemental-oxidant stream issuing from the opening of the at least one lance together aggregate a combined quantity of oxidant to provide a stoichiometric content of oxygen for combustion with the quantity of fuel that is introduced through the at least one existing burner; and e. supplying through the at least one lance an amount of supplemental oxidant having at least 60% of a stoichiometric content of oxygen for combustion of the quantity of fuel introduced into the burner, wherein the supplemental oxidant is fed into the furnace through the outlet of the at least one lance and issues from the outlet of the lance at a velocity of at least 300 m/s toward the flame issuing from the at least one existing burner.