Simultaneous removal of NO and SO from simulated marine ship flue gas in a novel wet scrubbing system based on divided diaphragm seawater electrolysis technology: efficiency optimization and economic assessment.

This work constructed a divided diaphragm seawater electrolysis system with two tandem packed towers for the synergistic removal of NO and SO. The first tower was mainly used to oxidize NO and SO by AC (active chlorine), and the second tower was used to further absorb NO. The factors affecting on NO removal, including ACC (active chlorine concentration), pH value, initial NO concentration and temperature in the oxidation tower were investigated. Moreover, the effect of different inlet gas concentrations and current values were explored. The results showed that with the increase of ACC, the NO and NO removal efficiency increased rapidly, but when the ACC was higher than 500 mg/L [Cl], the removal efficiency did not increase further in the oxidation tower. Low pH values in the oxidation tower were favorable for NO removal. NO removal efficiency reached a maximum at 40 °C. Higher NO and SO concentrations were favorable for NO removal. The decline of pH in the anode cell was not conducive to the storage of AC in the continuous electrolysis removal process. NO and SO were almost completely removed after being scrubbed in the oxidation and absorption towers. The relationship between current and removal efficiency of NO and SO in the oxidation tower was also analyzed. Finally, the removal mechanism and the application prospects were discussed.