LABORATORY INVESTIGATIONS INTO A NEW METHOD OF REDUCING NITROGEN-OXIDE IN THE PRESENCE OF FREE OXYGEN

This paper reports on investigations into au new method of reducing nitrogen oxide in the exhaust gases of engines which are operated under lean air/fuel conditions, as are, for instance, hydrogen-operated engines. The proposed method is called the ''ARD-technique'', which means Adsorption, Reduction or Reaction and Desorption. As compared with today's conventional catalytic processes, application of the ''ARD-technique'' means au completely new procedure in exhaust gas treatment. We present the results of laboratory research work using the ''ARD-techniquc'' in combination with commercially available adsorbers, oxygen-containing synthetic exhaust gases and gaseous hydrogen as the reduction medium. Depending on the relevant experimental parameters such as the temperature, the flow conditions and gas compositions, the measurements yield values between 50% and more than 90% for the obtainable NOx conversions.