A method for producing reduced iron that produces reduced iron by reducing iron oxide charged in a shaft furnace, in which a gas mixture which contains a reducing gas and a nitrogen gas, and has a predetermined temperature, is blown into the shaft furnace. The reducing gas contains 90 volume% or more of a hydrogen gas.

A method for producing reduced iron that produces reduced iron by reducing iron oxide charged in a shaft furnace, in which a heated gas mixture which contains a reducing gas and a nitrogen gas, the reducing gas containing 90 volume % or more of a hydrogen gas, is blown into the shaft furnace from a tuyere equipped at a lower portion of a reduction zone of the shaft furnace, at least part of the reducing gas is blown into a cooling zone of the reduced iron provided at a lower portion of the shaft furnace at normal temperature, and the reducing gas that has flowed up in the cooling zone is used for reduction of the iron oxide.

A method for producing reduced iron that produces reduced iron by reducing iron oxide charged in a shaft furnace, in which a heated gas mixture which contains a reducing gas and a nitrogen gas, the reducing gas containing 90 volume % or more of a hydrogen gas, is blown into the shaft furnace from a tuyere equipped at a lower portion of a reduction zone of the shaft furnace, at least part of the reducing gas is blown into a cooling zone of the reduced iron provided at a lower portion of the shaft furnace at normal temperature, and the reducing gas that has flowed up in the cooling zone is used for reduction of the iron oxide.

In a process and apparatus for the reduction of metal oxides to form metalized material by contact with hot reducing gas, which is produced at least partially by catalytic reformation of a mixture of—a gas containing carbon dioxide (CO.sub.2) and/or steam (H.sub.2O) with—gaseous hydrocarbons, the fuel gas for burners which provide the heat for the endothermal reformation processes which take place during the reformation is obtained at least partially from a partial quantity of the top gas produced during the reduction of metal oxides to form metalized material, wherein this partial quantity of the top gas, before it is used as a component of the fuel gas, is firstly subjected to dedusting and then to a CO conversion reaction, and the conversion gas obtained during the CO conversion reaction is subjected to CO.sub.2 removal after cooling.

In a process and apparatus for the reduction of metal oxides to form metalized material by contact with hot reducing gas, which is produced at least partially by catalytic reformation of a mixture of—a gas containing carbon dioxide (CO.sub.2) and/or steam (H.sub.2O) with—gaseous hydrocarbons, the fuel gas for burners which provide the heat for the endothermal reformation processes which take place during the reformation is obtained at least partially from a partial quantity of the top gas produced during the reduction of metal oxides to form metalized material, wherein this partial quantity of the top gas, before it is used as a component of the fuel gas, is firstly subjected to dedusting and then to a CO conversion reaction, and the conversion gas obtained during the CO conversion reaction is subjected to CO.sub.2 removal after cooling.

A method of operating a shaft furnace includes inserting a mixture including anthracite coal and coke into a cavity defined by the furnace, and disposing a metal feedstock within the cavity. The method includes injecting natural gas at a natural gas flow rate and a first quantity of oxygen gas at a first oxygen gas flow rate into the cavity simultaneously through at least one burner. The method also includes driving a second quantity of oxygen gas at a supersonic oxygen gas flow rate into the cavity through at least one lance, wherein the supersonic oxygen gas flow rate is greater than the first oxygen gas flow rate. The method also includes combusting the mixture within the cavity to produce a stack gas, melting the metal feedstock to produce a melted metal material, and monitoring the stack gas to thereby operate the shaft furnace. A shaft furnace is also disclosed.

A method for mitigating the buildup of direct reduced iron (DRI) clusters on the walls of a direct reduction (DR) furnace, comprising: injecting one or more of lime, dolomite, and another anti-sticking agent into a charge disposed within a reduction zone of the DR furnace, wherein the one or more of lime, dolomite, and another anti-sticking agent is injected into the charge by one or more of: (1) injecting the one or more of lime, dolomite, and another anti-sticking agent into a bustle gas stream upstream of a bustle of the DR furnace; (2) injecting the one or more of lime, dolomite, and another anti-sticking agent into the bustle gas stream in the bustle of the DR furnace; (3) injecting the one or more of lime, dolomite, and another anti-sticking agent into the bustle gas stream through a pipe collocated with a bustle gas port through which the bustle gas stream is introduced into the DR furnace; and (4) injecting the one or more of lime, dolomite, and another anti-sticking agent directly into the reduction zone of the DR furnace separate from the bustle gas stream.

A method for mitigating the buildup of direct reduced iron (DRI) clusters on the walls of a direct reduction (DR) furnace, comprising: injecting one or more of lime, dolomite, and another anti-sticking agent into a charge disposed within a reduction zone of the DR furnace, wherein the one or more of lime, dolomite, and another anti-sticking agent is injected into the charge by one or more of: (1) injecting the one or more of lime, dolomite, and another anti-sticking agent into a bustle gas stream upstream of a bustle of the DR furnace; (2) injecting the one or more of lime, dolomite, and another anti-sticking agent into the bustle gas stream in the bustle of the DR furnace; (3) injecting the one or more of lime, dolomite, and another anti-sticking agent into the bustle gas stream through a pipe collocated with a bustle gas port through which the bustle gas stream is introduced into the DR furnace; and (4) injecting the one or more of lime, dolomite, and another anti-sticking agent directly into the reduction zone of the DR furnace separate from the bustle gas stream.

Direct reduction process and plant for producing DRI comprising a reduction reactor and at least one reducing gas heater typically comprising a convective heating section and a radiant heating section for raising the reducing gas temperature to a level adequate for iron oxides reduction to metallic iron, typically above 850° C., wherein the reducing gas fed to the reduction reactor comprises a stream of reducing gas recycled from the reduction reactor and a make-up stream of coke oven gas containing carbon compounds which may form carbon deposits in the heating path of said heater, namely BTX and other complex carbon compounds. The heater is provided with means for feeding oxidizing agents, for example steam, steam and air and/or oxygen at predetermined heating tubes successively for eliminating the carbon deposits which may form inside the heating tubes of said heater without interrupting the operation of the plant. The make-up stream of cold COG can be combined with the recycled gas at a point in the gas heating path of the heater where the tubes have a skin wall temperature of at least 700° C., or when the mixture of recycled gas and COG is at a temperature above 700° C. for minimizing clogging or fouling of heating equipment.

Direct reduction process and plant for producing DRI comprising a reduction reactor and at least one reducing gas heater typically comprising a convective heating section and a radiant heating section for raising the reducing gas temperature to a level adequate for iron oxides reduction to metallic iron, typically above 850° C., wherein the reducing gas fed to the reduction reactor comprises a stream of reducing gas recycled from the reduction reactor and a make-up stream of coke oven gas containing carbon compounds which may form carbon deposits in the heating path of said heater, namely BTX and other complex carbon compounds. The heater is provided with means for feeding oxidizing agents, for example steam, steam and air and/or oxygen at predetermined heating tubes successively for eliminating the carbon deposits which may form inside the heating tubes of said heater without interrupting the operation of the plant. The make-up stream of cold COG can be combined with the recycled gas at a point in the gas heating path of the heater where the tubes have a skin wall temperature of at least 700° C., or when the mixture of recycled gas and COG is at a temperature above 700° C. for minimizing clogging or fouling of heating equipment.