Application of steam injection in iron ore sintering: fuel combustion efficiency and CO emissions

Improving the combustion efficiency of fuels is essential to reducing pollutant emissions in the iron ore sintering process. The sintering bed surface steam-injection technology has attracted significant research interest for its potential advantages in low-energy consumption and low emission. The effect of steam injection on fuel combustion efficiency and CO emission was studied by comparing the thermodynamic response from the sintering process before and after steam injection. The mechanism of improving combustion efficiency was also revealed. The results indicated that the sintering gas medium of H2O-H-2-N-2-O-2 with the blown steam improved the heat transfer conditions of fuel combustion and promoted the water gas reaction. The optimum state of steam injection was achieved at 15 min after ignition with 0.02 m(3) min(-1). The CO emission reduction is 10.91% compared with the base case. The combustion efficiency was 88.83%, 6.15% higher than conventional sintering, and the solid fuel consumption was reduced by 1.15 kg t(-1). It was indicated that steam injection would improve combustion efficiency and reduce solid fuel consumption. Meanwhile, the steam injection could improve the combustion kinetic conditions in the zone of unburned fuel and low oxygen partial pressure. It was conducive to the reaction of H2O with C and CO to convert the CO of reducing atmosphere to CO2, which in turn realized the complete combustion of fuel and CO and improved the efficiency of fuel combustion.