Unfiltered Diesel Engine Exhaust Treatment by Discharge Plasma: Effect of Soot Oxidation

Abstract

A cascaded system of electrical discharges (Non-thermal plasma), catalyst and adsorption process was investigated for the removal of oxides of nitrogen (NOx) and carbon monoxide (CO) from a Diesel engine raw exhaust. The three processes were separately studied first, and then the cascaded processes, namely plasma-catalyst and plasma-adsorbent, were investigated. In this paper main emphasis was laid on the effect of carbonaceous soot oxidation on the plasma treatment process. While the cascaded plasma-catalyst process exhibits a higher CO removal, the cascaded plasma-adsorbent process exhibits a higher NOx removal. The experiments were conducted under no-load. The plasma and adsorbent reactors were kept at room temperature throughout the experiment while the catalyst reactor was kept at 200°C/300°C.