Development of an Ammonia/SCR NOx Reduction System For A Heavy Duty Natural Gas Engine

An exhaust gas after-treatment system was developed to reduce oxides of nitrogen (NOx) emissions from a heavy duty diesel derived natural gas engine. The goal of the project was to reduce NOx emissions by 80% with a minimum ammonia slip and without negatively impacting other exhaust emissions.

This system utilized a stationary source, commercially available Selective Catalytic Reduction (SCR) catalyst and an ammonia (NH₃) injection system developed during the course of this project to reduce the NOx emissions.

Preliminary results indicate that NOx emissions were reduced by over 80% during transient operation with an ammonia slip of less than 2 ppm. This system had little impact on other engine emissions and engine performance.