Pilot-scale experiment of total marine diesel emission control using ozone injection and nonthermal plasma reduction

Since it is difficult to fulfill the recent stringent regulations governing marine diesel engine emission by means of combustion improvement alone, an effective aftertreatment technology is needed to achieve efficient NO_x and particulate matter (PM) simultaneous removal. In the present study, we design and investigate an effective aftertreatment system that employs a combination of ozone injection and nonthermal plasma (NTP) reduction for a marine diesel engine. The proposed technology offers the advantage of the useless of precious-metal catalysts, urea solution, and harmful heavy-metal catalysts. In the aftertreatment system, PM in the exhaust gas is first captured by a ceramic diesel particulate filter (DPF). Subsequently, the deposited PM is oxidized and removed by NTP-induced ozone injection. After the treatment, NO_x in the exhaust gas is treated by the following two flow processes using NTP combined with NO_x adsorbents: (a) adsorption and (b) desorption processes. These processes are repeated periodically and total emission control is achieved. Because the deposited PM and the desorbed NO_x are treated at high-concentration state by ozone and oxygen-lean NTP, the higher performance for total marine diesel emission control is recorded. The maximum efficiencies of NO_x and PM reduction were 94% and 95%, respectively.