CO2 emission evaluation and cost analysis of oxygen blast furnace process with sintering flue gas injection

In order to achieve ultra-low emissions of SO2 and NOx, the oxygen blast furnace with sintering flue gas injection is presented as a promising novel process. The CO2 emission was examined, and a cost analysis of the process was conducted. The results show that in the cases when the top gas is not circulated (Cases 1–3), and the volume of injected sintering flue gas per ton of hot metal is below about 1250 m3, the total CO2 emissions decrease first and then increase as the oxygen content of the blast increases. When the volume of injected sintering flue gas per ton of hot metal exceeds approximately 1250 m3, the total CO2 emissions gradually decrease. When the recirculating top gas and the vacuum pressure swing adsorption are considered, the benefits of recovered gas can make the ironmaking cost close to or even lower than that of the ordinary blast furnace. Furthermore, the implementation of this approach leads to a substantial reduction in total CO2 emissions, with reductions of 69.13% (Case 4), 70.60% (Case 5), and 71.07% (Case 6), respectively. By integrating previous research and current findings, the reasonable oxygen blast furnace with sintering flue gas injection can not only realize desulfurization and denitrification, but also achieve the goal of reducing CO2 emissions and ironmaking cost.