Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

Nigel Clark.


A large percentage of stationary engine applications are natural gas fueled. The cleanest of these large bore engines currently produce on the order of one gram of NOx per brake-horsepower hour (g/bhp-hr) of work done. The goal of this work is to reduce these emissions to 0.1 g/bhp-hr levels. Selective NOx Recirculation (SNR) is a technology which will help achieve these 0.1 g/bhp-hr levels. SNR has been proven in gasoline and diesel engines, with up to 90% NOx conversion rates being achieved, but not much is known about its overall efficiencies when used with natural gas engines. This technique involves adsorbing NOx from an exhaust stream, then selectively desorbing the NOx into a concentrated NOx stream, which is fed back into the engine, thereby converting a percentage of the concentrated NOx into harmless gases. Understanding the NO conversion process plays a major role in optimizing the SNR technology. The NO conversion process was modeled using CHEMKIN, a chemical kinetic solver. The results showed decreasing the air-fuel ratio of the engine to slightly rich operation and adding EGR could increase the experimentally measured NO conversion of approximately 20% up to 90%.