An Investigation of the Interaction between NOx and SOx in Oxy-Combustion

This study focuses on revealing the interaction of sulfur oxides (SO) and nitrogen oxides (NOx) and investigating the application of Fourier transform infrared (FTIR) spectroscopy to quantify SOx and NOx emissions from gas-phase oxy-combustion systems. The authors aim to contribute to the current state of knowledge by providing speciation data of NOx and SOx species and it elucidates the influence of nitric oxide (NO) on sulfur trioxide (SO3) generation. Detailed kinetic simulations revealed the influence of combustion parameters and the sensitivity analysis confirmed the dominating influence of hydrocarbon fragments on NO reduction. Accompanying experimental analysis exhibited higher reduction of NO to nitrogen (N-2) comparing to the predictions by the kinetic simulations. Moreover, the presence of NO in the system was observed to influence the SO3 generation to a variable degree based on the reaction set employed for kinetic simulations. Experimentally, slight decrease in SO3 concentration was observed in the presence of NO and it can be explained by the radical consumption by NO as SOx and NOx species share the same radical pool. The oxy-combustion mechanisms available in the literature can be improved further to be able to predict this interaction.