Visualization Study on the Methane Segregation Injection Technology in Iron Ore Sintering Process

It is widely reported that sinter strength would be weakened due to the damaged heat condition adopting low grade solid fuels, such as biomass. Moreover, the unevenly distributed heat in sintering bed is considered to be problematic on the quality of sintered ores. Aiming at solving these problems, the gaseous fuel (methane) injection method is experimentally investigated. Furthermore, the methane segregation injection method is firstly proposed. In this paper, the heat pattern in melting zone is recorded by the thermal infrared imager. The premixed air and methane is injected to the melting zone from the top surface of sintering pot and burned near the solid fuels combustion zone. Methane concentrations of 0.0% and 0.5% are tested, keeping the total calorific heat input unchanged. The non-segregation (0.5%-0.5%) and segregation (0.8%-0.2%) injection cases are also compared. The results indicate that methane injection method could extend the melting zone from the upstream without increasing the energy consumption, which is helpful to the improvement of sinter strength. From the infrared images, it is observed the melting zone becomes much more uniform after employing the segregation injection method. The present study provides an effective way to maintain the sinter quality when using low grade fuels in sinter plant, and minimize the imbalance of heat distribution in sintering bed.