A method includes combustion products from combustion of fuel with oxidant brought first through a first heat exchanging step (150;201), in which thermal energy is transferred from the combustion products to the fuel which is thereby preheated, and the cooled combustion products thereafter are brought through a second heat exchanging step (151;203), in which thermal energy is transferred from the cooled combustion products to the oxidant which is thereby also preheated. A related system for preheating the fuel and oxidant is also provided.

A method and a device for reducing iron-oxide-containing feedstocks, in which a reducing gas is fed to a reducing unit (1) containing the iron-oxide-containing feedstocks. The reducing gas is generated by introducing a process gas having reduction potential into a heating appliance (3) for heating the process gas, which is withdrawn as reducing gas therefrom. In the heating appliance (3), heat energy is transferred to the process gas. The heat energy is formed by combustion of a fuel gas containing organic substances, including coke oven gas with addition of technically pure oxygen. The flames of the combustion have an adiabatic flame temperature of above 1000° C., wherein, in the combustion of the fuel gas, at least some of the organic substances present in the fuel gas are cracked.

According to embodiments, disclosed is a method and system to maintain the soft and sparse slag characteristic favorable for an electric arc to efficiently transfer the energy to molten iron with the power input per furnace area higher than 600 KW/m2 while keeping FeO amount less than 5% in the slag and carbon amount higher than 2.5% in the product hot metal at a DRI melting furnace.

A method and an apparatus method for producing direct reduced iron (DRI) from iron ore using biomass as a source of reductant and as a heating source of the iron ore and electromagnetic energy as a further heating source in a furnace having multiple zones. The zones include a preheat zone and a reduction zone between an inlet for briquettes of iron ore and biomass and an outlet for direct reduced iron. The method includes counter-current movement of (a) briquettes of iron ore and biomass in a direction from the inlet to the outlet and (b) combustible gases in an opposite direction in the furnace.

A method and an apparatus for recycling a significant amount of heat within a linear hearth furnace by means of an endless conveyor that transports briquettes through the furnace from an inlet (briquette feed) end to an outlet (DRI discharge) end and then returns to the inlet end and transfers a significant amount of heat from the outlet end to the inlet end of the furnace.

The invention relates to the use of off-gas from furnaces (2) for the process of reduction of iron oxide. The bypass duct leads off-gas with reduction atmosphere directly into the reactor, passing through and back to join the main duct of dedusting system using negative pressure of the primary dedusting system. The off-gas directly heats up the iron oxide pellet and maintain the reduction atmosphere in the reactor and allow the reaction to proceed and prevent re-oxidation.

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 when producing the pig iron and/or producing the crude steel. According to the invention, the plant complex additionally has a chemical plant or biotechnological plant, connected to the gas-conducting system, and also energy storage for covering at least part of the electricity demand of the plant complex. Also the subject of the invention is a method for operating the plant complex.

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, a gas-conducting system for gases that occur when producing the pig iron and/or the crude steel, and a power-generating plant for electricity generation. The power-generating plant is designed as a gas-turbine power-generating plant or gas-turbine and steam-turbine power-generating plant and is operated with a gas that comprises at least a partial amount of the blast-furnace top gas that occurs in the blast furnace and/or a partial amount of the converter gas. The plant complex additionally comprises a chemical plant and a biotechnological plant, the power-generating plant, the chemical plant and the biotechnological plant being arranged in a parallel setup with regard to the gas supply. The gas-conducting system comprises an operationally controllable gas-distributing device for dividing the streams of gas.

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, a gas-conducting system for gases that occur in the production of pig iron and/or in the production of crude steel, and a power-generating plant for electricity generation. The power-generating plant is operated with a gas that comprises at least a partial amount of the blast-furnace top gas that occurs in the production of pig iron and/or a partial amount of the converter gas. According to the invention, a chemical or biotechnological plant is provided and connected to the gas-conducting system and arranged in parallel with the power-generating plant with respect to the gas supply. Externally obtained electricity and power-generating plant electricity are used to cover the electricity demand of the plant complex.

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.