The emission characteristics measurement of the iron-steel sintering flue gas shows that the SO₂ concentration is high in the middle of the sintering machine and low at the head and tail parts along the sintering direction. The dioxins concentration has positive a correlation with the flue gas temperature, and reaches a peak value as the temperature above 250℃. The proportion of the SO₂ concentration below 2000 mg/m³ occupies 63%, and the over 2000 mg/m³ occupies 37%. Therefore, the desulfurization efficiency should be higher than 90% and 96%, respectively. The proportion of the NO_x concentration below 300 mg/m³ is 86%, and the flue gas can be discharged directly without treatment. However, the proportion of NO_x concentration between 300 and 600 mg/m³ is 14%, and the denitration efficiency should be higher than 50%. The dioxins concentration between 1.0 and 5.0 ng TEQ/m³ has to be reduced to reach the national standard. According to the emission characteristics of high SO₂ and dioxins concentrations from the sintering flue gas, four kinds of multi-pollutant simultaneous control technologies are reviewed. Activated carbon adsorption belongs to an integrated control technology, while SDA (spray drying adsorption), MEROS (maximized emission reduction of sintering) and IOCFB (inner outer circulating fluidized bed) methods belong to collaborative control technologies based on the SO₂ absorbed by calcium-based sorbents and the dioxins adsorbed by activated carbon. Industrial applications of the four technologies are demonstrated and the removal efficiencies are compared with each other.

iron and steel industry  /  sintering flue gas  /  pollutant emission