2014 Volume 54 Issue 11 Pages 2541-2550
Flue gas recirculation (FGR) is being introduced into the sintering process with the aim of reducing the emissions of pollutants. The influences of FRG ratio and circulating flue gas properties such as components, contents and temperature on sintering process are researched. The results show that a cleaning production with good sinter indexes can be obtained in the case of FGR ratio of 30–40%. As the circulating flue gas passes through the sintering bed, the combustion speed of fuel is reduced with O2 content decreasing; CO in circulating flue gas can be reused due to its post-combustion in the sinter zone; the combustion speed and efficiency of fuel are reduced if CO2 content is too high; the velocity of gas-solid heat transfer is increased while the condensation at over-wet zone is intensified with the increase of H2O(g) content; and the thermal state of sintering bed is improved if the temperature of circulating flue gas is not too high. The sinter indices can be maintained in case of FGR with 15 vol%O2, 6 vol%CO2, less than 8 vol%H2O(g) and 150–250°C of inlet gas.