Diesel engine exhaust denitration using non-thermal plasma with activated carbon

Abstract

Vanadium-based catalysts are often used in selective catalytic reduction (SCR) technology for abating NO_x in diesel engine exhaust. However, their poor catalytic ability at low temperature, high toxicity and cost are big turnoffs. In this paper, the combination of non-thermal plasma (NTP) generated by dielectric barrier discharge and activated carbon (AC) is used to remove NO_x from diesel engine exhaust. The results show that the denitration efficiency of the NTP + AC + NH₃ system can reach 91.8% after 1 hour of NTP action at 0.5 kJ L⁻¹ energy density for simulated exhaust gas. The AC characterization results show that NTP increases the specific surface area of AC. AC is rather stable at 300 °C and the NTP + AC + NH₃ system can maintain high denitration efficiency for at least 5 hours. For real exhaust gas, the denitration efficiencies of the NTP + AC + NH₃ system can reach 92.5% (>300 °C) and 76.9% (<200 °C), respectively. There is great potential for NTP + AC + NH₃ technology to be a possible replacement for vanadium-based SCR in diesel engine exhaust denitration.