Pilot-Scale Combined Reduction of Accumulated Particulate Matter and NOx Using Nonthermal Plasma for Marine Diesel Engine

An effective NOx-reduction aftertreatment system for a marine diesel engine that employs combined nonthermal plasma (NTP) and adsorption is investigated. The system can also treat particulate matter (PM) that employs a diesel particulate filter (DPF) and its regeneration by NTP-induced ozone. The effect of the combined reduction of accumulated PM and NO
_x
is studied. The marine diesel engine of interest provides an output power of 1 MW at 100% of the engine load. The NO
_x
reduction is composed of repeated adsorption and desorption flow processes using NTP combined with NO
_x
adsorbents. With a view toward practical use, experiments on a higher number of cycles are carried out. The amount of adsorbents is 105 kg, which is greater than that in the authors' previous study. As a result, NO
_x
reduction efficiency by NTP is higher than in the previous study and is greater at higher amounts of adsorbents owing to higher NO
_x
desorption. Furthermore, DPF regeneration with plasma-induced O
₃
injection is achieved simultaneously. This aftertreatment system demonstrates an excellent energy efficiency of 114 g(NO
₂
)/kWh. The present after-treatment can generate a synergistic effect of PM and NOx reduction.