Simultaneous Removal of Nitrogen Oxides and Particulate Matters from Diesel Engine Exhaust using Dielectric Barrier Discharge and Catalysis Hybrid System

Dielectric barrier discharge (DBD) and catalysis hybrid process was used to remove nitrogen oxides and particulate matters from diesel engine exhaust. The DBD reactor converts a part of NO into NO₂, and then the exhaust gas containing the mixture of NO and NO₂ enters the catalytic reactor where both NO and NO₂ are reduced to N₂. The effect of energy density (power input divided by gas flow rate) and reaction temperature on the removal of nitrogen oxides was investigated with a stationary diesel engine. The hybrid process was able to remove about 80% of the initial nitrogen oxides at an energy density of 25 J/L and 150°C. The removal of particulate matters did not largely depend on the electrode structure, but it was a strong function of the energy density. On the basis of 80% removal efficiency, the energy yield for nitrogen oxides was 40 eV/molecule while that for particulate matters was 83 kJ/mg. The present study suggests that this kind of hybrid process can be applied to simultaneous removal of nitrogen oxides and particulate matters from diesel engine exhausts.