The invention relates to a plant complex for steel production comprising a blast furnace for producing pig iron, a converter steel mill for producing crude steel and a gas-conducting system for gases that occur in the production of pig iron and/or in the production of crude steel. According to the invention, the plant complex additionally has a chemical or biotechnological plant connected to the gas-conducting system and a plant for producing hydrogen. The plant for producing hydrogen is connected to the gas-conducting system by a hydrogen-carrying line. Also the subject of the invention is a method for operating the plant complex.

The present disclosure relates to a method for producing steel in an integrated metallurgical plant comprising at least one direct reduction reactor for directly reducing iron ore to give sponge iron, at least one electric furnace for melting the sponge iron to give pig iron or crude steel, at least one blast furnace for smelting iron ore to give pig iron, and at least one converter for refining pig iron to give crude steel. In accordance with the invention, the process gas discharged from the direct reduction reactor is admixed at least partly to the hot blast air and/or at least partly to an optional charging material, said air and/or said material being blown into the blast furnace.

In an embodiment, gas emitted during DRI processing and melting is collected and blown in refining, and gas emitted from the refining is collected and used in DRI processing, so that it is possible to circulate gas input to and emitted from each process in a DRI-Smelter-BOF (Basic Oxygen Furnace) scheme and achieve process optimization.

A Steel manufacturing method including the step of producing direct reduced iron (12) and a reduction top gas (13) in a direct reduction plant (1) using a reducing gas (11), the reduction top (13) being at least partly (13A) recycled as reducing gas (11), producing hot metal and a blast furnace top gas (21) in a blast furnace (2), wherein from 200 Nm3 to 700 Nm3 of hydrogen (20) per ton of hot metal to be produced are injected and the blast furnace top gas (21A) being at least partly sent to a biochemical plant (4) to produce hydrocarbons and producing molten metal and electric furnace gas in an electric furnace (3) using at least a part of the produced direct reduced iron (12).

A steel manufacturing method includes the steps of producing direct reduced iron in a direct reduction plant (1) using a syngas (70) resulting from the gasification of solid waste fuels, producing hot metal (22) and a blast furnace top gas (21) in a blast furnace (2) using a hot blast (20), the blast furnace top gas (21) being at least partly (21A) used into the direct reduction plant (1) and producing molten metal and electric furnace gas in an electric furnace (3) using the produced direct reduced iron (12). Associated network of plants.

A method for producing direct reduced metal material includes charging metal material to be reduced into a furnace space; evacuating an existing atmosphere from the furnace space so as to achieve an underpressure inside the furnace space; providing, in a main heating step, heat and hydrogen gas to the furnace space, so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapor to be formed; and condensing and collecting the water vapor in a condenser below the charged metal material. The providing of heat and hydrogen gas, and the condensing and collecting, are performed at least until a hydrogen atmosphere overpressure has been reached inside the furnace space, and so that no hydrogen gas is evacuated from the furnace space until the overpressure has been reached.

Method and system for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a furnace space (120); b) evacuating an existing atmosphere from the furnace space to achieve a gas pressure of less than 1 bar therein, c) providing heat and hydrogen gas into the furnace space, so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed, which hydrogen gas provision is performed so that a pressure of more than 1 bar builds up inside the furnace space; and d) before evacuating the built up overpressure, condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material. The invention is characterised in that it further comprises the step e) before evacuating the build up overpressure, providing a carbon-containing gas to the furnace space, so that the heated and reduced metal material is carburized by said carbon-containing gas.

Disclosed are systems and methods for efficiently integrating solid oxide electrolyzer cell (SOEC) systems with direct reduction (DR) processes. In various embodiments, a DR furnace produces steam in an exhaust stream. The exhaust stream is input to an inlet of a SOEC system. The SOEC system uses the steam to generate hydrogen and provide the hydrogen as a reducing agent to the DR furnace. The overall system efficiency may be improved by expelling the hydrogen from the SOEC system at higher temperatures than normal by not internally recycling the output stream of the SOEC system. System cost is reduced by removing components normally used for internal recycling. Additional efficiencies may be gained by capturing thermal energy released at various stages of the process and routing the captured thermal energy to other heating stages of the process.

Direct reduction systems and methods utilize a direct reduction shaft furnace to reduce the iron oxide with a reduction gas received from a reduction/recycle gas loop. An electric gas heating system disposed in the reduction/recycle gas loop heats up the reduction gas with make-up hydrogen and/or natural gas before introducing to the shaft furnace. The gas heating system includes, in sequence, a primary gas heating unit utilizing a direct or indirect heating mechanism to first heat the reduction gas to a temperature below 600 C. or above 700 C. to avoid carbon deposition in the gas heating system and a secondary gas heating unit utilizing a direct heating mechanism to second heat the reduction gas to the temperature between 900 C. and 1100 C.

The present invention pertains to the field of steel smelting, specifically to a method for steel production in a blast furnace and a converter based on carbon cycling. The method comprises the following steps: 1. Smelting iron in a blast furnace to obtain molten iron; 2. Introducing the aforementioned molten iron into a converter and carrying out steel refining within the converter to obtain molten steel and untreated converter gas; 3. Subjecting the untreated converter gas to pressurisation, deoxygenation, dehydration, and decarbonisation treatments to obtain synthesis gas and treated converter gas; 4. Recycling the treated converter gas back into the blast furnace to regulate the ratio of reductive gases within the furnace atmosphere.

Beneficial Effects: The method enables the cyclic utilisation of converter gas. By decarbonising the converter gas and recycling it back into the blast furnace, the content of reductive gases in the furnace atmosphere is enhanced. This promotes indirect reduction within the blast furnace while decreasing direct reduction, thereby reducing the consumption of carbonaceous fuel during the blast furnace iron smelting process and effectively lowering CO2 emissions.