Diesel NO_x aftertreatment by combined process using temperature swing adsorption, nonthermal plasma, and NO_x recirculation: NO_x removal accelerated by conversion of NO to NO_2

摘要

NO_x emitted from a stationary diesel engine generator was treated with a hybrid system that achieves NO_x reduction by means of nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N_2 and highly concentrated NO_x, which is effectively reduced by NTP treatment. The performance of NO_x treatment is enhanced by the re-injection of the concentrated NO_x into the engine intake. In this study, in particular, an oxidation catalyst was placed before the adsorber to enhance the adsorption of NO_x by converting NO to NO_2, with the aim of achieving a higher removal efficiency with a low adsorbent volume. The results show that it is possible for the treatment system to be downsized using the oxidation catalyst. The system's energy efficiency (the ratio of the amount of NO_x to the input electrical energy) ranges from 260 to 304g(NO_2)/kWh.