Steelmaking line and method of producing reduced iron

A steelmaking line comprising:

• a blast furnace configured to reduce iron oxide;
• a reducing furnace configured to reduce iron oxide;
• a methane synthesizer configured to synthesize methane from hydrogen gas and at least one of blast furnace gas and reducing furnace top gas, the blast furnace gas being generated from the blast furnace as a by-product and containing carbon dioxide, carbon monoxide, and hydrogen, and the reducing furnace top gas being discharged from a furnace top of the reducing furnace and containing carbon dioxide, carbon monoxide, and hydrogen;
• 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 methane gas synthesized by the methane synthesizer and at least one of the blast furnace gas and the reducing furnace top gas, to generate reducing gas containing carbon monoxide gas and hydrogen gas;
• a reducing gas blower configured to blow the reducing gas into the reducing furnace;
• and
• a supply path configured to supply the reducing furnace top gas to at least one of the methane synthesizer and the heat-reformer.