US Patent 8940076 Method for producing direct reduced iron with limited CO

Production method and apparatus for direct reduced iron (DRI), a.k.a sponge iron, by contacting iron oxides with recycled and regenerated hot reducing gases containing H2 & CO2. This invention decreases uncontained emission of CO2 to the atmosphere from combustion of carbon-bearing fuels in the reducing-gas heater by substituting, at least partially, a gas mainly comprising hydrogen in lieu of the usual carbon-bearing fuels. The hydrogen fuel stream, depleted of CO2 by means of a physical gas separation unit (which can be a PSA/VPSA type adsorption unit, a gas separation membrane unit or a combination of both such units) is derived from at least a portion of regenerated reducing gases being recycled to the reduction reactor. The derived hydrogen fuel stream is combusted in the reducing gas heater and/or other thermal equipment in the reduction plant, thus decreasing the CO2 emissions directly to the atmosphere.