SO₂ reduction in sintering flue gas by desulfurizer injection and activated coke technology

A large amount of air pollutants such as sulfur dioxide (SO₂), nitrogen oxides (NO_x), and dust can be produced in the process of iron ore sintering, which is the main source of steel pollutant emissions. A certain steel plant′s 435 m² sintering machine employs a countercurrent integrated process with activated coke for the reduction of pollutant emissions. The emission control equipment has experienced prolonged operation, leading to aging issues. Consequently, the concentration of SO₂ has exceeded the maximum threshold that the emission control system can withstand. Following emission control, the SO₂ concentration in the exhaust gas has surpassed acceptable limits, and it has adversely impacted the denitrification capability of the activated coke. In order to alleviate the pressure of active coke emission reduction, a desulfurizer injection emission reduction system was set up in the sintering flue, forming combined emission reduction technology of "process optimization" and "end-of-pipe treatment" for flue gas pollutants. The practical application results demonstrate that, following the injection of desulfurizing agents, the SO₂ concentration in the inlet flue gas of activated coke decreases from 853.78 mg/m³ to 668.76 mg/m³, meeting the operational conditions required for the normal operation of the activated coke desulfurization and denitrification process. This effectively addresses the issue of excessive SO₂ concentration. The dust concentration at the activated coke′s inlet increases from 25.48 mg/m³ to 31.39 mg/m³, with relatively minor increment in dust content in the exhaust gas. The emission control process′s desulfurization and denitrification efficiency remain unaffected by these changes and not experience any adverse effects. After the flue gas is reduced by the activated carbon system, the ultra-low emission requirement is reached. This study has reference value for the field industrial application of sintering flue gas pollutant treatment technology.