A process for producing reducing gas for use in the production of direct reduced iron (DRI) and fuel gas for use in a steel mill, including: compressing a coke oven gas (COG) stream in a compressor; passing the compressed coke oven gas stream through an activated charcoal bed to remove tars from the compressed coke oven gas stream; separating a hydrogen-rich gas stream from the compressed cleaned coke oven gas stream using a pressure swing absorption unit; providing the hydrogen-rich gas stream to a direct reduction shaft furnace as reducing gas; and providing a remaining gas stream from the pressure swing absorption unit to a steel mill as fuel gas. Both once-through and recycle options are presented. Optionally, basic oxygen furnace gas (BOFG) is added to the reducing gas.

A direct reduction process producing DRI from iron oxide particles by reduction at a about 750? C. with a reducing gas mainly H.sub.2 and CO, that also includes CO.sub.2, H.sub.20, and methane, a the reduction reactor and the top gas effluent from the reduction reaction after cooling/scrubbing is split. The resulting first top gas portion with a first hydrocarbon-containing make-up gas passes through a catalytic reformer yielding an improved hot reducing gas first effluent. The second top gas portion passes through a CO.sub.2 removal unit and then with the second hydrocarbon-containing make-up gas passes through a heater yielding a hot CO.sub.2-lean recycle reducing gas second effluent. The first and second effluents are fed to the reducing zone of the reduction reactor as the reducing gas reactant. The flow rate of at least the second of the two make-up gases is regulated to control the carbon content of the DRI produced.

The present invention concerns a method for producing carbon monoxide (CO), comprising the steps of: providing a gaseous initial input stream comprising carbon dioxide (CO2) to a plasma zone: at least partially converting said CO2 to CO by: (a) igniting a plasma in the plasma zone: (b) extracting an output stream from the plasma zone, said output stream comprising less CO2 than said first stream, and recycling said output stream as a gaseous input stream to said plasma zone and further converting CO2 to CO by performing steps (a) and (b), thereby obtaining a final output stream comprising more CO and less CO2 than the initial input stream.

Methods and systems for producing DRI utilizing a petroleum refinery bottoms (i.e. heavy fuel oil, vacuum residue, visbreaker tar, asphalt, etc.) or petroleum coke gasifier and a hot gas cleaner. Cooling of the hot synthesis gas generated by the petroleum refinery bottoms or petroleum coke gasifier to <200 C is not necessary. Rather, the synthesis gas from the petroleum refinery bottoms or petroleum coke gasifier is desulfurized and dedusted at high temperature (>350 C) using a hot gas cleaner, well known to those of ordinary skill in the art, although not in such an application. This hot gas cleaner may be high pressure or low pressure.

Apparatus for supplying blast to a blast furnace (1) having a plurality of hot blast stoves (4, 5, 6), each stove including a cold blast inlet, a fuel inlet, an air supply inlet, a hot blast outlet, and a waste gas outlet; a waste heat recovery unit (30) connected to a fuel supply, the stove fuel inlet and the cold blast inlet. The stove waste gas outlets are connected to the cold blast inlets, whereby stove waste gas from one stove (5) is supplied, via the waste heat recovery unit, as cold blast to another stove (4).

A method of direct reduction of iron (DRI) is disclosed, the method comprising generating metallic iron by removing oxygen from iron ore using a reducing gaseous mixture with excess carbon monoxide that produces an excess CO.sub.2 by-product is provided. CO.sub.2 by-product is optionally sequestered. A system for carrying out the method is also disclosed.

An injection regulation and control device includes blast furnace tuyeres for introducing rich oxygen or pure oxygen to form tuyere raceways. Temperature-adjusting injection openings are evenly formed in the circumferential direction of a blast furnace and inject a hydrocarbon component-containing injection object to the blast furnace. The temperature-adjusting injection openings are located, in an axial direction, within a height range where a soft melting dripping zone is located and are not lower than the positions of the blast furnace tuyeres. The hydrocarbon component-containing injection objects are enabled to undergo a thermal cracking reaction by utilizing the temperature in the vicinity of the tuyere raceways to form a hydrocarbon thermal cracking heat absorption area. Gas products generated by the thermal cracking reaction of the hydrocarbon component-containing injection objects increase the blast furnace gas volume. Redundant heat in a lower high-temperature area is carried to the upper part of the blast furnace.

A direct reduced iron manufacturing system includes a gas reformer for supplying steam to reform natural gas, a gas heater being a heating unit for heating a reformed gas reformed by the gas reformer to a predetermined temperature, a direct reduction furnace for reducing iron ore directly into reduced iron using a high-temperature reducing gas, an acid gas removal unit having an acid gas component absorber and a regenerator for releasing the acid gas, and a recovery gas introduction line for supplying a recovery gas released from the regenerator to each of a reforming furnace of the gas reformer and a furnace of the gas heater.

A blast furnace system is used wherein the coke rate is decreased by recycling upgraded top gas from the furnace back into its shaft section (which upgraded top gas is heated in a tubular heater prior to being recycled). The top gas, comprising CO, CO.sub.2 and H.sub.2, is withdrawn from the upper part of the blast furnace; cooled and cleaned of dust, water, and CO.sub.2 for increasing its reduction potential and is heated to a temperature above 850 C. before being recycled thus defining a first gas flow path used during normal operation of the blast furnace. Uniquely, a second gas flow path for continued circulation of top gas selectively through the heater and a cooler during operation interruptions of the blast furnace allows time for gradual controlled cool down of the heater in a manner to avoid heat-shock damage to the tubular heater.

Methods and systems for producing direct reduced iron having increased carbon content, comprising: providing a reformed gas stream from a reformer; delivering the reformed gas stream to a carbon monoxide recovery unit to form a carbon monoxide-rich gas stream and a hydrogen-rich gas stream; and delivering the carbon-monoxide-rich gas stream to a direct reduction furnace and exposing partially or completely reduced iron oxide to the carbon monoxide-rich gas stream to increase the carbon content of resulting direct reduced iron. The carbon monoxide-rich gas stream is delivered to one of a transition zone and a cooling zone of the direct reduction furnace. Optionally, the method further comprises mixing the carbon monoxide-rich gas stream with a hydrocarbon-rich gas stream.