Oxidation of Carbon Soot Layer using Pulsed Discharge Plasma 2001-01-3511

Simultaneous removal of NO_x 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 NO_x. 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.