Diesel NOx aftertreatment by combined process using temperature swing adsorption, NOx reduction by nonthermal plasma, and NOx recirculation: Improvement of the recirculation process

Abstract

NOx emitted from a stationary diesel engine generator was treated with a hybrid system comprising NOx reduction by nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N2 and highly concentrated NOx, which is effectively reduced by NTP treatment. Improved treatment performance and efficiency are achieved by re-injecting the NTP-treated gas mixture into the engine intake. The system comprises two switchable adsorption chambers; the operation of this system was simulated by using a one-chamber system. The maximum energy efficiency for NOx treatment is 200g(NO2)/kWh. The respective contributions of NTP and injection of N2 and NOx to the performance were theoretically analyzed. The analysis predicts that high energy efficiency and high NOx-removal efficiency can be simultaneously achieved with this system but miniaturization of the adsorption chambers will be a challenge.