P. E. Duarte, Business Director; J. Becerra, Vice-President of Engineering, HYL Technologies SA de CV (Tenova HYL), Monterrey, Mexico; pablo.duarte@mx.tenovagroup.com

In integrated blast furnace (BF) based steel mills, there is always an excess of coke oven gases, converter gases and blast furnace top gases, which are normally used in power stations. An alternate approach is to use this available energy for the production of direct reduced iron, which can be fed as metallic charge to BF providing an increase in production of crude steel or alternatively, a significant reduction of fossil fuels specific consumption. The optimized utilization of primary fossil energy will have the effect of significantly reducing the specific CO₂ emissions per ton of crude steel. The specific CO₂ emissions via the conventional BF/BOF route is about 1.7 — 1.8 t of CO₂/t crude steel, even on an optimized process route basis. Utilizing the DRI being produced with natural gas, coke oven gas and BF top gas as metallic charge to BF or in an electric arc furnace, allows significant reductions in absolute and specific CO₂ emissions. The Energiron DR process intrinsically includes a CO₂ absorption system for the selective elimination of CO₂, leaving only 30 % of total carbon entering the process as non-selective emission through flue gases from the PG heater stack. CO₂ stripping is achieved by using the top gas waste sensible heat, avoiding the need of additional energy requirements. With this proposed simple approach, a complete non-selective CO₂-free emissions “green”DR plant is now available in the market. Its applicability and efficiency has to be evaluated according to the specific conditions at each single site.

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4. Duarte, P. E.; Tavano, A.; Zendejas, E.: Achieving carbon-free emissions via the Energiron DR process, AISTech 2010, May 2010, Pittsburgh, USA.