Ruthenium-Based Catalyst in EGR Leg of a D-EGR Engine Offers Combustion Improvements Through Selective NO _X Removal

A recent collaborative research project between Southwest Research Institute^® (SwRI^®) and the University of Texas at San Antonio (UTSA) has demonstrated that a ruthenium (Ru) catalyst is capable of converting oxides of nitrogen (NO_X) emissions to nitrogen (N₂) with high activity and selectivity. Testing was performed on coated cordierite ceramic cores using SwRI’s Universal Synthetic Gas Reactor^® (USGR^®). Various gas mixtures were employed, from model gas mixes to full exhaust simulant gas mixes. Activity was measured as a function of temperature, and gaseous inhibitors and promoters were identified. Different Ru supports were tested to identify ones with lowest temperature activity. A Ru catalyst can be used in the exhaust gas recirculation (EGR) leg of a Dedicated-EGR (D-EGR) engine [1,2], where it uses carbon monoxide (CO) and hydrogen (H₂) present in the rich gas environment to reduce NO_X to N₂ with 100% efficiency and close to 100% selectivity to N₂. The NO_X-free EGR gases can then be fed into the intake air without concerns that the NO_X will lead to pre-ignition under high engine efficiency operating conditions. This catalysis may find application in other rich-burn and reducing gas mixture environments.