The influences of power supply on lean NO<inf>x</inf> removal by plasma-facilitated selective catalytic reduction

Abstract

Plasma-facilitated selective catalytic reduction(PF-SCR) was considered as a promising method to realize controlling of NO x in the lean-burn engine exhaust. But the influences of power frequency lack detailed description. Powers with frequency 50Hz, 800Hz and 10kHz were applied respectively to produce plasma in the experiments, and twostage process consisting of plasma pretreatment of the exhaust before flow over a lean NO x catalyst was studied. The results showed that 50Hz power was more efficient on NO x removal than other two power supplies according to energy density. It may be attributed to that highest voltage was supplied by 50Hz power in the three powers at the same energy density, which led to more NO and C 2 H 4 oxidation after plasma. As a result, NO 2 , more active reactant than NO, was produced more by 50Hz power. The gas components in the exit of plasma reactor were identified by GC-MS and GC, and the transforming routes of nitrogen element and carbon element were also concluded simply.