Blast furnace hydrogen-rich metallurgy-research on efficiency injection of natural gas and pulverized coal

Natural gas (NG) can replace part of pulverized coal (PC) in the blast furnace (BF) injection as the clean and highcalorific hydrogen-rich energy, which can reduce environmental pollution and energy consumption in molten iron production. In this work, the method of numerical simulation is used to first compare and analyze the differences of NG and PC mixed injection and only PCI on the thermal state, gas composition and PC burnout in the tuyere and raceway of a Russian BF. The research results show that when NG and PC are injected, the temperature near the wall of the tuyere is higher, but the average temperature in the raceway is lower. Then we further clarify the influences of injection parameters on the transmission and combustion performances of PC under the condition of mixed injection of NG and PC. It can be concluded that with the diameter of the NG lance increases, the oxygen consumed by NG combustion in the tuyere increases, resulting in a decrease in the burnout of PC. The change of the NG lance position has relatively less apparent effect on transmission and combustion within the tuyere and raceway of the BF. In addition, as the NG injection (NGI) rate increases from 47 m(3)/t to 67 m(3)/t, the oxygen consumption of NG in the tuyere and raceway increases, causing the decrease of PC burnout from 70.11% to 68.31%, the reduction of the CO content but the increase of the H-2 content in the primary gas, which can effectively reduce CO2 emissions.