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 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 method for producing syngas in combined operation with a metallurgical plant which comprises at least one blast furnace for producing crude iron, a converter steel mill and a coke-oven plant. Part of the blast-furnace top gas that is produced in the production of crude iron and/or part of the converter gas that occurs in the converter steel mill and/or part of the coke-oven gas that is produced in the coke-oven plant are mixed. By choosing the gas streams that are brought together to form a mixed gas and/or by changing the mixing ratios of the gas streams that are brought together, at least two streams of useful gas are produced, differing with regard to their composition and respectively prepared to form streams of syngas.

The invention relates to a method for producing syngas in combined operation with a metallurgical plant which comprises at least one blast furnace for producing crude iron, a converter steel mill and a coke-oven plant. Part of the blast-furnace top gas that is produced in the production of crude iron and/or part of the converter gas that occurs in the converter steel mill and/or part of the coke-oven gas that is produced in the coke-oven plant are mixed. By choosing the gas streams that are brought together to form a mixed gas and/or by changing the mixing ratios of the gas streams that are brought together, at least two streams of useful gas are produced, differing with regard to their composition and respectively prepared to form streams of syngas.

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, 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.

A method for operating a blast furnace for producing of pig iron, comprising the steps of including heating a stream of hydrocarbon gas and a stream of steam in a first heater to provide a heated stream of hydrocarbon gas and steam, feeding and partially reforming the heated stream of hydrocarbon gas and steam in a pre-reformer to provide a stream of partially reformed syngas, heating a first stream of blast furnace gas from the blast furnace and the stream of partially reformed syngas in a second heater, before or after their mixing together, to provide a heated carbon feed stream, reforming the heated carbon feed stream in a secondary reformer to provide a second stream of syngas, and feeding said second stream of syngas to the shaft of the blast furnace.

A method for operating a blast furnace for producing of pig iron, comprising the steps of including heating a stream of hydrocarbon gas and a stream of steam in a first heater to provide a heated stream of hydrocarbon gas and steam, feeding and partially reforming the heated stream of hydrocarbon gas and steam in a pre-reformer to provide a stream of partially reformed syngas, heating a first stream of blast furnace gas from the blast furnace and the stream of partially reformed syngas in a second heater, before or after their mixing together, to provide a heated carbon feed stream, reforming the heated carbon feed stream in a secondary reformer to provide a second stream of syngas, and feeding said second stream of syngas to the shaft of the blast furnace.

A method of operating an ironmaking or steelmaking plant with low CO.sub.2-emissions is provided. Hydrogen and oxygen are generated by water decomposition and at least part of the generated hydrogen is injected as a reducing gas into one or more ironmaking furnaces with off-gas decarbonation and reinjection into the furnaces of at least a significant part of the decarbonated off-gas and at least part of the generated oxygen is injected as an oxidizing gas in the one or more ironmaking.