Method and apparatus for producing direct reduced iron

In a process of reducing iron oxide-containing particles in a moving bed reduction reactor with a reducing gas formed therein from make-up gases mainly composed of gaseous hydrocarbon and H2O to produce direct reduced iron, DRI, said reactor having an upper reduction zone and a lower cooling zone, a reducing gas recycle loop including said reduction zone and a cooling gas recycle loop including said cooling zone, which process comprises:

• feeding into the reduction zone iron oxide-containing particles,
• feeding into said reduction zone a hot enhanced recycle reducing gas and make-up gases largely comprised of H2, CO, gaseous hydrocarbon, and H2O,
• causing said gases to flow through the portion of the moving bed in the reduction zone to effect reduction of such particles therein and to effect reformation of gaseous hydrocarbon with H2O and any CO2 therein to yield a resulting depleted residual reducing gas,
• said H2 and CO being mainly derived by said reformation within said reactor,
• withdrawing the depleted residual reducing gas from said reduction zone for conditioning and recycling,
• depleting the H2O and CO2 reduction reaction by-products from the depleted residual reducing gas to yield a resulting upgraded recycle reducing gas,
• re-heating the upgraded recycle reducing gas in a heater to above about 850° C.,
• feeding make-up gases substantially comprised of gaseous hydrocarbon and H2O to said upgraded recycle reducing gas in said loop,
• feeding free-O2-containing gas to said re-heated upgraded recycle reducing gas to further raise the temperature of such recycle gas to above about 1000° C. by partial combustion of at least the gaseous hydrocarbon to yield the hot enhanced recycle reducing gas used to feed the reduction zone and thereby complete the reducing gas recycle loop,
• flowing still-hot DRI from the reduction zone down into said cooling zone,
• circulating a cooling gas in said cooling gas recycle loop including through said cooling zone to cool-down said DRI,
• withdrawing from said cooling zone for recycling along said cooling loop at least a portion of said cooling gas warmed up after having cooled said DRI,
• cooling and scrubbing said withdrawn portion,
• mixing such withdrawn portion with a compatible pressurized make-up cooling gas, and
• thereafter recycling along the cooling gas including the make-up cooling gas back into said cooling zone thereby completing the cooling gas recycle loop, and
• discharging the cooled DRI from said cooling zone;
• the improvement comprising
• the recycling of the cooling gas in said cooling gas recycle loop is wholly by means of one or more ejectors driven by the stream of cooling gas make up in the form of high pressure merchant-supplied natural gas as the motive power for each such ejector.