Mathematical Modeling of the Energy Consumption and Carbon Emission for the Oxygen Blast Furnace with Top Gas Recycling

Abstract

The ironmaking process is the most significant source of CO2 emission in the iron and steel industry, which generates large quantities of greenhouse gases. Recently, oxygen blast and top gas recycling have been applied to the blast furnace to improve the energy efficiency and reduce the pollution from the ironmaking process. However, as a new ironmaking technology, the oxygen blast furnace with top gas recycling (TGR-OBF) is still under development. This paper focuses on the investigation of the energy consumption and carbon emission for the TGR-OBF process by modeling the stack, the bosh, the combustion zone, and the gas recycling system. Effects of the key parameters in the TGR-OBF process on the carbon consumption of reactions and the energy consumption of the system are investigated by orthogonal experiments. Our results indicate that the TGR-OBF process has the advantages of reducing energy consumption and CO2 emission. The low temperature and high reducing environment in the new furnace is favorable to lower the coke gasification and increase the reaction rate of iron oxide. The recycling of the top gas can significantly reduce CO2 emission, and the main advantage comes when the stripped CO2 is stored. A comprehensive model is established to investigate the oxygen blast furnace with top gas recycling (TGR-OBF) process. The low temperature and high reducing environment in TGR-OBF can reduce coke consumption and increase the reduction rate of iron oxide. Compared with the conventional operation, the TGR-OBF (Case 2) decreases the direct CO2 emission by 55.2% and net CO2 emission by 35.7%.