Reduction of CO2 emissions as a result of using hydrogen-rich reduction gases for producing direct reduced iron

The use of hydrogen-rich gases such as natural gas or coke oven gas as a reduction agent for the production of direct reduced iron (DRI) as well as its processing to steel in an electric arc furnace, will open up new possibilities to lower the CO2 emission per t of steel to results which will be substantially below those achieved in conventional crude steel production via the blast furnace/BOF route. While the conventional way, in spite of optimally adjusted process conditions (<300 kg coke/t of hot metal) will result in a CO2 emission of about 1600 kg CO2/t of crude steel, direct reduction on natural gas basis with the electric arc furnace will enable a reduction of emissions between 29 and 39% down to 1135 - 962 kg CO2/t of crude steel. The use of hydrogen being processed by coke oven gas will lead to results of about 780 kg CO2/t of crude steel. Considering that coke oven gas is only available in integrated iron and steel plants (blast furnace/coke oven plant), the integration of a DR plant into an existing iron and steel plant with a coke oven plant, with the direct use of the (partly cleaned) coke oven gas without separating the hydrogen, will achieve results of 1230 kg CO2/t of crude steel, with the DRI being melted in an electric arc furnace. The production of hydrogen from coal or heavy fuel oil for later use as a reduction agent in the production of DRI leads only to a minimal reduction of the specific CO2 emission.