Experimental Study on DeNOx Performance by Plasma-Catalyst (Ag, Au/Al2O3) System

Plasma-catalyst (Ag, Au/Al₂O₃) systems were applied to NOx reduction in a model lean-burn engine exhaust gas. Also, DeNOx test of real diesel exhaust gas was performed by plasma-Ag/Al₂O₃ system. In the case of model exhaust gas, the catalytic activity for NOx reduction was enhanced by the assistance of plasma in the wide temperature range. The NOx conversion efficiency of plasma-Ag/Al₂O₃ was 40∼90% under the condition of C₃ H₆ 3200ppm (C₁/NOx = 5.96) and 10% O₂ over the temperature range of 250∼400°C. The plasma-Au/Al₂ O₃ system showed remarkable low temperature NOx reduction activity at 100∼250°C.

The real engine full flow test was performed for 70% of the full load and at engine speed of 1500rpm. NOx removal of 46% from the diesel exhaust gas was achieved by the plasma-Ag/Al₂O₃ catalyst system at 364°C(C₁/NOx = 6). In the case of higher C₁/NOx = 10, the NOx conversion increased up to 73% at 381°C. Also, DeNOx engine tests were performed for full load of 1500, 2000 and 2500rpm. The DeNOx efficiency was about 45%, which was similar to the laboratory test results.