A hydrogen release and storage system (100) of the present invention includes a hydrogen compound member (101), a container (102) that accommodates the hydrogen compound member (101), a heating apparatus (103) configured to heat the inside of the container (102), a cooling apparatus (104) configured to cool the inside of the container (102) and a water supply apparatus (105) configured to supply water to the container (102).

A method and system for operating a seal gas compressor utilized in a direct reduction process including: monitoring a pH level of a water stream used in the seal gas compressor, wherein the pH level of the water stream is affected by a reformer flue gas stream that comes into contact with the water stream, wherein the monitoring step is carried out one or more of upstream of the seal gas compressor and downstream of the compressor; and adjusting the pH level of the water stream to maintain the pH level of the water stream within a predetermined range based on feedback from the monitoring step. The method includes maintaining the pH level of the water stream upstream of the seal gas compressor in a range between 7.5 and 10 and maintaining the pH level of the water stream downstream of the seal gas compressor in a range between 7.8 and 9.5.

Embodiments relate to systems and methods for regenerating and recirculating a CO, H.sub.2 or combinations thereof utilized for metal oxide reduction in a reduction furnace. The reduction furnace receives the reducing agent, reduces the metal oxide, and generates an exhaust of the oxidized product. The oxidized product is transferred to a mixing vessel, where the oxidized product, a calcium oxide, and a vanadium oxide interact to regenerate the reducing agent from the oxidized product. The regenerated reducing agent is transferred back to the reduction furnace for continued metal oxide reductions.

A method and system for operating a seal gas compressor utilized in a direct reduction process including: monitoring a pH level of a water stream used in the seal gas compressor, wherein the pH level of the water stream is affected by a reformer flue gas stream that comes into contact with the water stream, wherein the monitoring step is carried out one or more of upstream of the seal gas compressor and downstream of the compressor; and adjusting the pH level of the water stream to maintain the pH level of the water stream within a predetermined range based on feedback from the monitoring step. The method includes maintaining the pH level of the water stream upstream of the seal gas compressor in a range between 7.5 and 10 and maintaining the pH level of the water stream downstream of the seal gas compressor in a range between 7.8 and 9.5.

A process for the production of sponge iron and a system for the production of sponge iron. The process includes the steps of: producing electrolytic hydrogen and oxygen by electrolysis of water; producing methanol by reacting the electrolytic hydrogen with carbon dioxide; storing the methanol; reforming the methanol using water and/or oxygen to provide carbon dioxide and released hydrogen; providing the released hydrogen as a component portion of a reducing gas to a direct reduction shaft; and reducing iron ore in the direct reduction shaft using the reducing gas to produce the sponge iron.

Provided is a steelmaking line contributing to the realization of a method that achieves energy saving and CO.sub.2 emission reduction when producing reduced iron from iron oxide. The steelmaking line comprises: a blast furnace configured to reduce iron oxide; a reducing furnace configured to reduce iron oxide; a methane synthesizer configured to synthesize methane from blast furnace gas and/or furnace top gas, and hydrogen gas; a blower configured to blow the methane gas synthesized by the methane synthesizer into the blast furnace; a heat-reformer configured to heat or heat-reform the blast furnace gas and/or the furnace top gas, and the methane gas synthesized by the methane synthesizer, to generate reducing gas; a reducing gas blower configured to blow the reducing gas into the reducing furnace; and a supply path configured to supply the furnace top gas to the methane synthesizer and/or the heat-reformer.

Systems for producing iron may include (a) a reactor configured to receive iron ore and a reducing gas, and from these produce iron; and (b) a carbon dioxide reduction electrolyzer configured to produce at least carbon monoxide and/or a hydrocarbon. Such systems may be configured to transport carbon dioxide produced by the reactor and/or produced by combustion of a gas generated by the reactor to a cathode side of the carbon dioxide reduction electrolyzer. Such systems may be further configured to transport at least a portion of the carbon monoxide and/or hydrocarbon produced by the carbon dioxide reduction electrolyzer to the reactor, where the carbon monoxide and/or hydrocarbon serves as at least a part of the reducing gas.

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.

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.

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.