Patent ID: 6551549
Filing Date: 2003-04-22
Classification: C21B,Y02P

Abstract:
Apparatus for the direct reduction of mineral iron comprising:a vertical reduction furnace to achieve therein reactions of reduction of the iron mineral, said furnace comprising at least two different reducing zones disposed vertically distanced therebetween, an upper mouth to feed the mineral iron into said furnace from above, first and second high temperature gas inlets to inject a mixture of high temperature gas into said at least two different reducing zones, an outlet for removing burnt gas from an upper part of said furnace, and a discharge zone for removing reduced mineral from the lower part of said furnace; a pre-heater having an inlet operably connected to said outlet of said furnace for pre-heating at least a part of said burnt gas to a temperature between about 650Â° and 950Â° C.; piping connecting an outlet of said pre-heater to said first and second high temperature gas inlets of said furnace said piping dividing downstream of said preheater into a first inlet pipe connected to said first high temperature gas inlet and a second inlet pipe connected to said second high temperature gas inlet; a source of and a reducing gas based on H2 and CO from a process outside said furnace connected to said piping to mix the burnt gas pre-heated to a temperature between about 650Â° and 950Â° with the reducing gas to produce a first mixture of gas; a source of hydrocarbon and oxygen connected to said first and second inlet pipes for injecting into said first mixture of gas at least a hydrocarbon and oxygen, so as to increase the temperature of said first mixture of gas between about 800Â° and 1150Â° C.; first valves provided in said first and second inlet pipes for controlling the quantity of said mixture of high temperature gas injected into each one of said at least two different reducing zones; and second valves provided for controlling the quantity of said hydrocarbon and oxygen injected into said first and second inlet pipes to optimize the reducing and reforming process within the furnace.