Per: José Adilson de Castro (universidade federal fluminense), giulio antunes de medeiros (universidade federal fluminense), leonardo martins da silva (universidade federal fluminense), elizabeth mendes de oliveira (centro federal de educação tecnológica)
Abstract:
A numerical simulation procedure is proposed for analyzing hydrogen, oxygen, and blast furnace gas (BFG) injections mixed with pulverized coal within the tuyeres of large blast furnaces. The massive use of hydrogen-rich gas is highly attractive to the steelmaking blast furnace in the context of carbon net-zero hot metal production. Likewise, this new approach allows for increasing productivity and decreasing the specific emissions of carbon dioxide toward a net-zero carbon ironmaking technology. Nevertheless, mixed gas with pulverized coal injections is a complex technology with drastic changes in the inner temperature and gas flow patterns, in addition to their effects on the chemical reactions and energy exchanges. Focusing on the evaluation of inner furnace status under such complex operation a comprehensive mathematical model has been developed using the multi-interactions of phases theory. The model treats simultaneously the lump solids (sinter, small coke, pellets, granular coke, and iron ores), gas, liquid metal, slag, and pulverized coal phases. The governing conservation equations are formulated for momentum, mass, chemical species, and energy simultaneously discretized and solved using the finite volume technique. The numerical model is verified against a reference operational condition using pulverized coal of 195 kilograms per ton of hot metal (kg/thm). Thus, combined injections of varying fuel hydrogen, BFG, and oxygen concentrations are simulated for 160 and 220 kg/thm of coal injection. Theoretical analysis showed that stable operations conditions could be achieved with a productivity increase of 47%. Finally, we demonstrated that the net carbon utilization per hot metal ton decreased 21%.
