Oxidation of Carbon Soot Layer using Pulsed Discharge Plasma 2001-01-3511
Simultaneous removal of NOx and carbon soot from diesel exhaust has been experimentally studied. We tested two types of plasma reactor (filter type and pellet type) to remove carbon soot and NOx. These reactors were driven by pulsed square high voltage. Simulated gas was used in this experiment. The filter-type plasma reactor consists of a stainless mesh tube as a high voltage electrode covered with a quartz fiber filter (or glass cloth). In the filter-type plasma reactor, about 97-98% of suspended particles were effectively collected on the surface of the filter with a weak discharge (Specific input energy value around 10J/L). The collected carbon soot was oxidized to CO2 with the SIE of about 200 J/L. A yield of generated CO2 per energy was 26mg/kJ. On the other hand, in the packed pellet-type plasma reactor, carbon soot was efficiently oxidized to CO2 compare with the filter-type plasma reactor. A yield of generated CO2 per energy was 204mg/kJ. With lower SIE of 50J/L, the experimental result indicated that the carbon soot obtained from the diesel exhaust was oxidized to CO2. At the same time 50% of NO was oxidized to NO2. Using C2H4 addition, more than 90% of NO was oxidized to NO2.