Patent ID: 6546717
Filing Date: 2003-04-15
Classification: B01D,F01N,F02B,Y02A,Y02T

Abstract:
A method of combatting air pollution from a lean-burn engine whose exhaust gas comprises NO and SO2, comprising the steps of:oxidizing NO to NO2 selectively over oxidizing SO2 to SO3 by contacting the exhaust gas with ozone at a temperature of from 50Â° C. to 250Â° C. and in the absence of material catalytic for oxidizing SO2 to SO3, wherein NO2 produced is adsorbed by an adsorbent which adsorbs the NO2 when the exhaust gas is lean and releases the adsorbed NO2 when the exhaust gas is rich, and the exhaust gas is periodically made rich to release the adsorbed NO2; reducing NO2 to nitrogen; and discharging unreacted SO2 to atmosphere.