Experimental and numerical performance evaluation of a thermal oxidizer for industrial lean burn natural gas engines

Abstract

Methane slip in industrial lean burn natural gas engines is a significant source of greenhouse gas emissions. With growing regulations on the emissions of hydrocarbon pollutants, especially methane, new reduction technologies for these engines are needed. This research investigates the performance of a new type of thermal oxidizer, known as an Oxiperator, for reducing methane emissions from a lean burn natural gas engine. This study begins with baseline testing of a Cummins QSK19G engine to determine the optimal operating conditions for the Oxiperator. It was found that the most optimal operating condition for the Oxiperator is with a high air-to-fuel mixture. It was then followed by a performance evaluation of the Oxiperator to assess its ability to oxidize methane in the exhaust. The first key result from this performance evaluation is that the minimum concentration of total hydrocarbons required to maintain oxidation was found to be 4400 ppm. The second key result was that the lowest temperature that the Oxiperator can be where the oxidation reaction is still recoverable is 815 °C. The performance of the Oxiperator was also modeled using CONVERGE CFD. The simulation results were then compared to the actual test results. The CFD model shows that it could be an effective tool for predicting the performance of the Oxiperator, though there are many areas for improvement. This research contributes to the development of methane emissions control technologies for lean burn natural gas engines and identifies considerations for improvements on the future Oxiperator design.