Method and system for energy-optimized and CO2 emission-optimized iron production

A process for producing liquid pig iron or liquid primary steel products and sponge iron from charge materials that are formed from iron ore, comprising:

• reducing the charge materials directly into sponge iron in a first reduction zone, smelting the sponge iron is in a melter gasifier while carbon carriers and gas containing oxygen are fed in, whereby a generator gas containing CO and H2 is produced;
• discharging the generator gas from the melter gasifier;
• first cooling and then dedusting the generator gas produced in the melter gasifier for producing a reducing gas;
• introducing a first partial amount of the reducing gas obtained in the dedusting as a first reducing gas into the first reduction zone, where the first partial amount of the reducing gas is converted to and drawn off as top gas;
• subsequently dust scrubbing the top gas and after the dust scrubbing of the top gas, partly or completely subjecting the top gas to compression and CO2 scrubbing;
• after the CO2 scrubbing of the top gas, admixing at least a first partial amount of the CO2-scrubbed gas with the generator gas that leaves the melter gasifier, wherein the generator gas is cooled;
• obtaining a second partial amount of the reducing gas in the dedusting and admixing the second partial amount of the reducing gas with a second partial amount of the CO2-scrubbed gas, after being heated, for producing a second reducing gas;
• feeding the second reducing gas to at least one further reduction zone for direct reduction of further iron ore,
• wherein the second partial amount of the reducing gas recovered in the dedusting makes up between 5% by volume and 50% by volume, of the overall amount of the reducing gas obtained in the dedusting.