Sampling and Measuring NO and NO2 in Combustion Systems

摘要

This study examines the effects of probe configuration and combustor operating parameters on NO/NO2 distributions in flames. A fundamental understanding of physical and chemical phenomena pertinent to NO2 measurement in combustion systems is important because of the gas's significant role in smog formation and in combustion processes, as well as its hazard to human health. A flat flame burner system was modified, refurbished and optimized for operation over a range of reaction throughputs, fuel-air equivalence ratios, and combustion processes. Comprehensive NO/NOx measurements were made using various probes. Low NO2 levels were recorded with cooled and uncooled quartz probes; uncooled stainless steel probes showed virtually no differences between NO and NOx; water cooled stainless steel probes measured significant NO2 concentrations; water cooled sterling silver probe results were similar to those of cooled stainless steel probes. Data indicate that probe configuration, burner pressure, and stoichiometry significantly affect NO/NOx measurements. A kinetic model was developed to clarify and explain sampling probe effects on NO/NO2 interconversions within the probes.