Prediction of NOx and CO Emissions from an Industrial Lean-Premixed Gas Turbine Combustor Using a Chemical Reactor Network Model

NOx and CO emissions from gas turbines are limited by European legislation to 25 ppmvd for natural gas operations. To meet this objective, and that of future legislation, it is necessary to develop a numerical tool that can predict NOx and CO emissions quickly and accurately. In this study, a chemical reactor network (CRN) is developed based on computational fluid dynamics (CFD). A combustor is modeled by using Star-CCM+, a commercial CFD code. The network consists of 22 chemical reactor elements, which act as different reaction zones in the combustor. The predictions of exhaust emissions in this work were carried out using the CHEMKIN code and the full GM 3.0 chemical kinetics mechanism. The model combustor tests were conducted at different conditions using various flow rates and equivalence ratios for the main and pilot injector at three different inlet temperatures. The predicted NOx and CO emission results closely matched the experimental data. The present study focuses on the effects of inlet temperature and pilot-to-total fuel ratio on NOx emissions at various load conditions using NO formation pathway analysis.