A Pilot-Scale Experiment for Total Marine Diesel Emission Control Using Ozone Injection and Nonthermal Plasma Reduction

Due to the fact that 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 required to achieve the efficient simultaneous removal of NO_x and particulate matter (PM). In the present study, we designed and investigated 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 not requiring precious-metal catalysts and harmful heavy-metal catalysts as well as urea solution. In this aftertreatment system, PM in the exhaust gas is first captured by a ceramic diesel particulate filter. Subsequently, the deposited PM is oxidized and removed by NTP-induced ozone injection. After the PM treatment, NO_x in the exhaust gas is treated by adsorption followed by NTP-combined desorption and reduction processes. These processes are repeated periodically, and total emission control is achieved. Since the deposited PM and the desorbed NO_x are treated at a high-concentration state by ozone and oxygen-lean NTP, a higher performance for total marine diesel emission control is recorded. The maximum efficiencies of NO_x and PM reduction were 94% and 95%, respectively.