REGENERATIVE FURNACE OPERATION WITH AN OXIDANT COMPRISING 60 TO 85 PERCENT OF OXYGEN

Disclosed is a method of operating a furnace containing a charge to heat the charge, comprising wherein gaseous oxidant comprising 60 vol. % to 85 vol. % oxygen is passed through a heated regenerator and into the furnace, so that the oxidant is heated to emerge from an oxidant port at a temperature of 500° C. to 1400° C., and gaseous fuel is fed into said furnace through two or more fuel ports; and the heated oxidant and fuel are combusted in the furnace to produce gaseous hot products of said combustion which heat the charge; and then the flow of oxidant through the regenerator into the furnace is discontinued, and said combustion products are passed into said oxidant port and through and out of said cooled regenerator to heat said regenerator, wherein the temperature of the combustion products that pass out of said regenerator is at least 500° C.; under dimensional and operational conditions which attain functional and economic advantages.