posted on 2021-10-22, 23:44authored byXiaolong Liu, Yang Zou, Ran Geng, Tingyu Zhu, Bin Li
In this work, steel slag slurry was used in combination with O3 oxidation for the simultaneous removal of SO2 and
NOx in a laboratory-scale wet flue gas
desulfurization process. The effects of the oxidation temperature,
steel slag concentration, initial SO2 concentration, and
pH value on the desulfurization and denitrification efficiencies were
studied. The results showed that the highest NOx removal efficiency occurred at an oxidation temperature of
90 °C. With an increase of the oxidation temperature above 90
°C, the denitrification efficiency decreased due to the decomposition
of N2O5. The effect of the SO2 concentration
on denitrification was complicated. When the concentration of SO2 was 500 ppm, generation of SO32– promoted the absorption of NO2. However, higher SO2 concentrations strengthened the competitive absorption of
SO2 and NOx. In the pH range
of 8.5–4.5, the denitrification efficiency was maintained at
about 96%. The component analyses of the aqueous solution and the
solid residue were conducted to investigate the compositions of the
absorption products. The results showed that NO3– and SO42– were the major anions in
the aqueous solution. The nitrogen balance was analyzed to be 95.8%,
clearly illustrating the migration and transformation path of nitrogen.
In the solid residue, most alkaline substances were consumed, and
the final products were mainly CaSO4 and FeO. Accordingly,
the reaction mechanism of simultaneous desulfurization and denitrification
using steel slag combined with ozone oxidation was proposed.