Material and energy flow simulation and economic analysis for a novel suspension ironmaking techonology

Currently, the blast furnace process is the most dominant ironmaking process, which produces more than 90% of the world's iron. However, because of its significant environmental issues, especially caused by carbon dioxide emission, an alternative intensive ironmaking process using environment friendly technology has been required to be applied to decrease the number of the blast furnace plants. Novel "gas-solid suspension ironmaking technology" based on gas-solid reduction of domestically available fine iron ore concentrate was conceived to solve this issue. So far, preliminary experiments using hydrogen showed prominent results at high temperature (1200°C-) and with a large amount of excess hydrogen, which overcomes the equilibrium of the reduction of wustite by hydrogen.;A pilot/commercial scale process flow sheet using this technology was constructed and simulated by a commercial software METSIM. As possible flow sheet configurations, the "1-step process" and "2-step process" were simulated and compared for the cases using purchased hydrogen, combined with a steam-methane reforming (SMR) process, and with direct use of natural gas without reforming. Throughout simulations, the term "excess driving force" was introduced and used to express the degree of excess hydrogen required to overcome the equilibrium.;Using the results of material and energy balance obtained by simulations, economic feasibility analysis based on "discount cash flow analysis" was performed. In the analysis, Net Present Value (NPV) was calculated using estimated capital and operating costs. Sensitivity analysis was also performed on the estimated NPV using several item cost variations.