Temperature control of iron ore reducing fluidized beds

Claim 1

THE PROCESS FOR TREATING IRON-CONTAINING ORES TO REDUCE THE HEMATITE TO MAGNETITE IN A REACTOR HAVING A PLURALITY OF SUPERPOSED FLUIDIZED ZONES COMPRISING THE STEPS ESTABLISHING AND MAINTAINING IN A VERTICAL SUBSTANTIALLY CYLINDRICAL VESSEL AT LEAST THREE SUPERPOSED FLUIDIZED ZONES OF IRON-CONTAINING ORE OF WHICH IN THE LOWER TWO ZONES REDUCTION CONDITIONS ARE MAINTAINED AND IN THE UPPER ZONE SOLIDS PREHEATING CONDITIONS ARE MAINTAINED, INTRODUCING INTO THE LOWEST REDUCTION ZONE AN OXYGEN CONTAINING GAS AND A LIQUID HYDROCARBON FUEL, SAID GAS CONTAINING INSUFFICIENT OXYGEN FOR COMPLETE COMBUSTION OF SAID LIQUID HYDROCARBON FUEL, MAINTAINING SAID LOWEST ZONE AT A TEMPERATURE SUFFICIENTLY ELEVATED TO CAUSE PARTIAL OXIDATION OF SAID LIQUID HYDROCARBON FUEL WITH SAID OXYGEN CONTAINING GAS IN THE PRESENCE OF SAID IRON-CONTAINING ORE THEREBY PRODUCING REDUCING AGENTS FOR REDUCING SAID HEMATITE TO MAGNETITE AND AT LEAST A PORTION OF THE HEAT FOR MAINTAINING THE IRON-CONTAINING ORE AT THE REDUCTION TEMPERATURE, SUCCESSIVELY PASSING SAID PARTIALLY COMBUSTED GASES UPWARD THROUGH SAID INTERMEDIATE REDUCTION ZONE AND SAID PREHEATING ZONE TO PARTIALLY REDUCE THE IRON-CONTAINING ORE IN SAID INTERMEDIATE REDUCTION ZONE AND TO PREHEAT THE INCOMING IRON-CONTAINING ORE BEING SUPPLED TO SAID PREHEAT ZONE, SAID INCOMING IRON-C ONTAINING ORE PASSING FROM SAID PREHEAT ZONE DOWNWARDLY THROUGH SAID INTERMEDIATE REDUCTION ZONE INTO SAID LOWER REDUCTION ZONE WHEREIN THE DESIRED REDUCTION OF THE IRON-CONTAINING ORES IS COMPLETED, DISCHARGING SAID REDUCED ORE FROM SAID LOWER REDUCTION ZONE, INTRODUCING INTO SAID INTERMEDIATE REDUCTION ZONE A LIQUID HYDROCARBON FUEL WHENEVER THE TEMPERATURE OF SAID REDUCTION ZONE HAS DROPPED BELOW A PREDETERMINED MINIMUM, DISCHARGING SPENT FLUIDIZING GASES FROM SAID PREHEAT ZONE, SAID GASES CONTAINING RESIDUAL REDUCING AGENTS AND POTENTIAL HEAT VALUES, AND UTILIZING SAID HEAT VALUE IN SAOD PREHEAT ZONE BY BURNING A PORTION OF SAID DISCHARGE GASES WHEREBY THE HEAT GENERATED BY SAID HEAT VALUES IS MIXED WITH THE UPFLOWING GASES FROM SAID INTERMEDIATE REDUCTION ZONE AND SUPPLIED INTO SAID PREHEAT ZONE.