Desulfurization and denitrification experiments in SDA system: A new high-efficient semi-dry process by NaClO2

An integrated and effective method to realize simultaneous desulfurization and denitrification by the Spray Dryer Absorption (SDA) method combined with the NaClO2 was carried out in this paper. The optimum conditions on desulfurization were verified, as well as the cooperative effect and removal mechanism between SO2 and NO was speculated. The results showed that the best desulphurization efficiency was obtained when NaOH was added into the slurry with a liquid-solid ratio of 6:1. At the same time, the stirring speed was 250 r/min and the rotational speed of the atomizer was 250 r/s. In addition, NaClO2 was selected as the liquid oxidizer to remove NO, and the efficiencies ranged from 65% to 90% with different concentration. When the flue gas temperature was 70 degrees C, the denitrification efficiency was the best. The concentration of NaClO2 was 1.5%, and the slurry stirring speed and atomizer speed was 250 r/min and 300 r/s, respectively. When SO2 and NO coexisted in the flue gas, not only did SO2 removal efficiency remain high, but NO removal efficiency also exceeded 80%. Obviously, SO2 had an obvious positive effect on the removal of NO, and the related mechanisms as well as some theories were studied in this research.