System for energy optimization in a plant for producing direct-reduced metal ores

A system for energy optimization in a plant for producing direct-reduced metal ores, comprising:

• at least one reduction unit, a gas separation device for separation of gas mixtures, a gas heating device connected upstream of the reduction unit and downstream of the gas separation device in a direction of gas flow;
• a supply line for feeding process gas from at least one plant for pig iron production and toward the reduction unit;
• an expansion turbine fitted between the gas separation device and the gas heating device and connected upstream of the reduction unit, the turbine is configured such that a drop in pressure between the gas separation device and the reduction unit is able to be converted into forms of energy usable for operation of further components of the plant for producing direct-reduced metal ores;
• and
• the turbine is configured for regulating a volume of process gas flowing from the gas separation device to the reduction unit and/or for regulating pressure of the process gas exiting the gas separation device for separation of gas mixtures.