Effects of experimental parameters on simultaneous removal of SO₂ and NO by VUV/H₂O₂ advanced oxidation process in a pilot‐scale photochemical spraying tower

Abstract

BACKGROUND: Emissions of SO 2 and NO from flue gas have caused serious environmental pollution issues. UV/vacuum ultraviolet(VUV)-activated H 2 O 2 advanced oxidation technology is one of the most promising processes to realize the simultaneous removal of SO 2 and NO. From the application perspective, it is necessary to carry out further research in a pilot-scale photochemical reactor with industrial conditions and actual coal-fired flue gas running conditions. RESULTS: Results showed that SO 2 removal efficiency can reach 100% under most experimental conditions. An increase of the VUV irradiation intensity, H 2 O 2 concentration and solution pH can promote NO removal, but the growth rate of that gradually slows down. It is not conducive to NO removal when the flue gas flow and NO concentration increases. Increasing liquid-gas ratio has dual effects on NO removal; NO removal efficiency increases at first, and then decreases sharply. SO 2 concentration has no great impact on removal of NO. Results of ion chromatography (IC) demonstrate that SO 4 2− and NO 3 − are the major removal products of SO 2 and NO. CONCLUSION: The VUV-activated H 2 O 2 advanced oxidation technology is suitable for industrial application. The investment and operating costs of this technology are lower than those of the combined processes NH 3 -SCR and Ca-WFGD.

Simultaneous removal of NO and SO2 from flue gas by FeIIEDTA/sodium dithionite solutions

“…Although SO 2 and NO can be removed by the limestone‐lime method and selective catalytic reduction (SCR) processes, respectively, the combination of these methods for simultaneous desulfurization and denitrification requires a large area, intricate processes and high operating costs, which results in ammonia leakage and spent catalysts. Hence, the simultaneous removal of SO 2 and NO by a single process has become a leading research direction in the field of air pollution control …”

“…Hence, the simultaneous removal of SO 2 and NO by a single process has become a leading research direction in the field of air pollution control. 7 Complexation absorption technologies are extensively studied currently for simultaneous desulfurization and denitrification, among which Fe II EDTA, as a conventional and efficient complex absorbent of NO and SO 2 in the wet absorption of exhaust gas, has been investigated extensively since the 1970s by many research groups because of its fast complexing ability on NO. 8 Fe II EDTA can rapidly catch NO to produce the ferrous-nitrosyl complex Fe II EDTA-NO [Eqn (1)], for which the equilibrium constant is generally 10 7 mol −1 .…”