Removal of NOx and SO2 from simulated ship emissions using wet scrubbing based on seawater electrolysis technology

- A ship emission control strategy based on seawater electrolysis technology was proposed and investigated.
- The pH-dependent distribution of active chlorine species has a significant impact on NOx removal efficiency.
- High removal efficiency could be achieved by electrolyzed seawater in double stage reactors.

This paper proposed a promising method for removal of NOx and SO2 from simulated ship emissions by wet scrubbing using electrolyzed seawater. Several factors were investigated on removal efficiencies of NO and NOx in a semi-continuous bubble column reactor. Results showed that NOx removal was enhanced with the increase of active chlorine concentration, NO inlet concentration, reaction temperature, and concentrations of coexisting gases (CO2 and O2), but was inhibited with increasing gas flow rate. The pH of the electrolyzed seawater had a significant impact on the NOx removal. Then, simultaneous removal of NOx and SO2 in both single stage and double stage reactors were studied preliminarily. Maximum removal efficiencies of NOx and SO2 from simulated ship emissions (NOx 1000 ppm, O2 15%, CO2 5%, SO2 751 ppm) were 92% and 100% respectively under optimum conditions. Final products (NO2− and NO3−) of the process effluent were analyzed by the ion chromatography, and reaction pathways were also discussed.