NOx Removal in Diesel Engine Exhaust Using Nonequilibrium Plasma and Chemical Process.

In the previous studies, we proposed a two stage plasma-chemical process for control of NOx gas emitted from electric power plants and factories. This process consists of a plasma process to oxidize NO to NO2 with low electric power and low byproducts, and a chemical process to reduce NO2 to N2 using Na2SO3. Almost 100% NOx removal efficiency was achieved for simulated exhaust gas using this hybrid method. In the present study, this method was first applied to a real exhaust gas from a diesel engine and the removal characteristics of NOx were examined. As a result, the plasma reactor could oxidize nearly 100% of NO to NO2 with the 50% load in the diesel engine. The NO oxidation decreased with increase in gas temperature and humidity. Using the plasma-chemical hybrid method, a 87% NOx removal efficiency was obtained with the specific energy density. 140J/L.