Correlating Impacts of Injected Fuels on Carbon Emissions in Blast Furnace with Computational Fluid Dynamics Modeling

Abstract

A major challenge for steelmaking is the reduction of CO2 emissions. In this regard, the blast furnace (BF) is critical due to the high associated CO2 levels. This investigation assesses the impact of tuyere‐injected fuels on BF CO2 emissions. Specifically, computational fluid dynamics results obtained previously at Purdue University Northwest are analyzed to obtain CO2 emissions when natural gas (NG), syngas, hydrogen, or hydrogen/NG are injected. CO2 emissions are compared with those produced when 95 kg of NG/thm is injected. Among these scenarios, the largest CO2 reduction occurs when 102 kg of syngas/thm (COG feedstock #1) is injected at 973 K, reducing CO2 by 190.6 kg thm−1. The largest CO2 reduction obtained with NG occurs when 130 kg thm−1 is injected at 600 K, reducing emissions by 65 kg thm−1. H2 injection also reduces CO2, but requires careful adjusting to reach stable operation. For instance, injecting 35 kg of H2/thm reduces CO2 by 52 kg thm−1. Increasing gaseous injection rates can significantly reduce CO2 emissions, with fuel preheating providing an addendum, but high injection rates can lead to unstable operation. Furthermore, results show a correlation between CO2 emissions and average temperature of shaft region for multiple fuels and injection conditions.