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

Vanadium-based catalyst is often used in selective catalytic reduction (SCR) technology for abating NOx in diesel engine exhaust. However, its 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 NOx from diesel engine exhaust. The results show that the denitration efficiency of the NTP+AC+NH3 system can reach 91.8% after 1 hour’s NTP action at 0.5kJ/L 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 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 as a possible replacement for the vanadium-based SCR in diesel engine exhaust denitration.