Provision of a gas production apparatus that can stably produce a product gas with carbon monoxide as its main component from a separated gas including carbon dioxide as a main component.

The gas production apparatus 1 consists of the following: a separation and capture section 5, which separates and captures separated gas containing mainly of carbon dioxide from the exhaust gas taken from the line of the exhaust gas equipment; a reaction section 4 including at least a reactor, which is connected to downstream of the separation and capture section 5, contains a reducing agent that generates carbon monoxide through a reduction reaction of carbon dioxide brought into contact with the separated gas, and is capable of separating at least some of oxygen atoms separated from carbon dioxide; a pressure regulating section 7 connected to downstream of the reactor 4 to regulate the pressure of the separated gas supplied to the reactor; and the flow regulating section 6 connected on the upstream of the separation and capture section 5 and regulates the flow rate of the separated gas supplied to the reactor.

System and method for producing steel is provided that efficiently reduce carbon dioxide emissions. A steel production system includes: a first gas generating section configured to obtain a first gas by converting carbon monoxide, to carbon dioxide, in a gas containing the carbon dioxide and carbon monoxide; a reducing gas supply section 3 configured to supply a reducing gas containing a reducing substance to reduce a reducing agent, the reducing agent containing metal oxide to reduce carbon dioxide and being oxidized by contact with the carbon dioxide; and a reaction section 4 including a plurality of reactors 4a and 4b, respectively connected to at least one of the first gas generating section and the reducing gas supply section 3, and the reducing agent arranged in the reactors 4a and 4b, the reaction section being capable of switching between the first gas and the reducing gas to be supplied to each of the reactors 4a and 4b, wherein a second gas is configured to be supplied to a blast furnace, the second gas being obtained by contacting the first gas supplied to the reactors 4a and 4b with the reducing agent to convert the carbon dioxide to carbon monoxide and the second gas having the carbon monoxide as a main component.

System and method for producing steel is provided that efficiently reduce carbon dioxide emissions. A steel production system includes: a first gas generating section configured to obtain a first gas by converting carbon monoxide, to carbon dioxide, in a gas containing the carbon dioxide and carbon monoxide; a reducing gas supply section 3 configured to supply a reducing gas containing a reducing substance to reduce a reducing agent, the reducing agent containing metal oxide to reduce carbon dioxide and being oxidized by contact with the carbon dioxide; and a reaction section 4 including a plurality of reactors 4a and 4b, respectively connected to at least one of the first gas generating section and the reducing gas supply section 3, and the reducing agent arranged in the reactors 4a and 4b, the reaction section being capable of switching between the first gas and the reducing gas to be supplied to each of the reactors 4a and 4b, wherein a second gas is configured to be supplied to a blast furnace, the second gas being obtained by contacting the first gas supplied to the reactors 4a and 4b with the reducing agent to convert the carbon dioxide to carbon monoxide and the second gas having the carbon monoxide as a main component.

Methods and systems for producing steel or similar molten-iron-containing materials in melting or smelting furnaces utilizing pre-reduced iron ore, known also as direct reduced iron (DRI) or sponge iron, wherein the emission of CO.sub.2 and other greenhouse gases is significantly low. Such methods and systems are based on producing DRI in a direct reduction furnace with a reducing gas comprising hydrogen; melting at least a portion of the DRI in a melting furnace in order to generate hot gases; producing steam and/or hot water using the heat contained in the hot gases. From the steam and/or hot water hydrogen is produced by electrolysis, at least a portion of which is fed to the direct reduction furnace as a component of the reducing gas to produce the DRI.

A method for operating a metallurgical furnace and a simplified way of providing synthesis gas for a metallurgical furnace, includes the following steps performing a combustion process outside the metallurgical furnace by combusting a carbon-containing material with an oxygen-rich gas to produce an offgas, which offgas is a CO.sub.2 containing gas; and combining the offgas, while having an elevated combustion-induced temperature due to the combustion process, with a hydrocarbon-containing fuel gas to obtain a first gas mixture having a temperature above a reforming temperature necessary for a reforming process, preferably a dry reforming process; the first gas mixture undergoing the reforming process, thereby producing a synthesis gas containing CO and H.sub.2, the reforming process being performed non-catalytically; and feeding the synthesis gas into the metallurgical furnace.

A method for operating a metallurgical furnace and a simplified way of providing synthesis gas for a metallurgical furnace, includes the following steps performing a combustion process outside the metallurgical furnace by combusting a carbon-containing material with an oxygen-rich gas to produce an offgas, which offgas is a CO.sub.2 containing gas; and combining the offgas, while having an elevated combustion-induced temperature due to the combustion process, with a hydrocarbon-containing fuel gas to obtain a first gas mixture having a temperature above a reforming temperature necessary for a reforming process, preferably a dry reforming process; the first gas mixture undergoing the reforming process, thereby producing a synthesis gas containing CO and H.sub.2, the reforming process being performed non-catalytically; and feeding the synthesis gas into the metallurgical furnace.

A method for operating a blast furnace, including collecting a blast furnace gas from the blast furnace, the blast furnace gas being a CO.sub.2 containing gas, combining the blast furnace gas with a fuel gas to obtain a gas mixture, the fuel gas being a hydrocarbon containing gas, subjecting the gas mixture to a reforming process, thereby producing a synthesis gas containing CO and H.sub.2; and feeding at least a portion of the synthesis gas and an oxygen-rich gas into the blast furnace, where the blast furnace gas is combined with the fuel gas while containing substantially the same amount of CO.sub.2 as when exiting the blast furnace and wherein the blast furnace gas is combined with the fuel gas in an over-stoichiometric ratio, so that the synthesis gas contains a surplus portion of the blast furnace gas.

A method for operating a blast furnace, including collecting a blast furnace gas from the blast furnace, the blast furnace gas being a CO.sub.2 containing gas, combining the blast furnace gas with a fuel gas to obtain a gas mixture, the fuel gas being a hydrocarbon containing gas, subjecting the gas mixture to a reforming process, thereby producing a synthesis gas containing CO and H.sub.2; and feeding at least a portion of the synthesis gas and an oxygen-rich gas into the blast furnace, where the blast furnace gas is combined with the fuel gas while containing substantially the same amount of CO.sub.2 as when exiting the blast furnace and wherein the blast furnace gas is combined with the fuel gas in an over-stoichiometric ratio, so that the synthesis gas contains a surplus portion of the blast furnace gas.

The present invention provides a reduction system and method that can be operated with any proportion of gaseous hydrogen-containing gases and gaseous hydrocarbon-containing gases having the possibility of continuing its operation, ensuring an high process availability and negligible loss of production, when the gaseous hydrogen-containing gas for any reason is not available and allow the substitution of the gaseous hydrogen-containing gas with a gaseous hydrocarbon-containing gas with minor adjustments in the plant operation. The reduction system of the invention is designed to be implemented in new and already built direct reduction plants to operate efficiently and has lower capital and operation costs.

The present invention provides a reduction system and method that can be operated with any proportion of gaseous hydrogen-containing gases and gaseous hydrocarbon-containing gases having the possibility of continuing its operation, ensuring an high process availability and negligible loss of production, when the gaseous hydrogen-containing gas for any reason is not available and allow the substitution of the gaseous hydrogen-containing gas with a gaseous hydrocarbon-containing gas with minor adjustments in the plant operation. The reduction system of the invention is designed to be implemented in new and already built direct reduction plants to operate efficiently and has lower capital and operation costs.