High Reduction Efficiencies of Adsorbed NOx in Pilot-Scale Aftertreatment Using Nonthermal Plasma in Marine Diesel-Engine Exhaust Gas

An efficient NOx reduction aftertreatment technology for a marine diesel engine that combines nonthermal plasma (NTP) and NOx adsorption/desorption is investigated. The aftertreatment technology can also treat particulate matter using a diesel particulate filter and regenerate it via NTP-induced ozone. In this study, the NOx reduction energy efficiency is investigated. The investigated marine diesel engine generates 1 MW of output power at 100% engine load. NOx reduction is performed by repeating adsorption/desorption processes with NOx adsorbents and NOx reduction using NTP. Considering practical use, experiments are performed for a larger number of cycles compared with our previous study; the amount of adsorbent used is 80 kg. The relationship between the mass of desorbed NOx and the energy efficiency of NOx reduction via NTP is established. This aftertreatment has a high reduction efficiency of 71% via NTP and a high energy efficiency of 115 g(NO2)/kWh for a discharge power of 12.0 kW.