Predictions of NO_X in a Laboratory Pulverized Coal Combustor Operating under Air and Oxy-Fuel Conditions

Abstract

A new approach to modeling NO_X under oxy-fuel combustion conditions in a simple staged-oxidizer flow field is presented. The approach is centered on the combination of devolatilization and char oxidation models with a detailed kinetic mechanism for light hydrocarbon combustion. NO_X chemistry is included by the user's selection of the detailed mechanism, while the devolatilization model consists of the chemical percolation devolatilization (CPD) model modified to be independent of oxidizer composition. Literature-based correlations provide elemental composition of the volatiles. Model predictions were compared to experimental measurements with good agreement in several respects. The model provides insights for the interpretation of experimental oxy-fuel combustion NO_X results, and recommendations are given for computational fluid dynamics (CFD) modeling of NO_X in oxy-fuel combustion.

Keywords:

• Coal and char combustion
• Modeling
• NO_X
• Oxy-fuel

ACKNOWLEDGMENTS

The authors gratefully acknowledge funding for this work provided by the U.S. Department of Energy under University Coal Research Grant No. DE-FG26–05NT42530 and American Air Liquide. We also thank Dr. Peter Glarborg for providing input files for the SKG03 mechanism, and Dr. Thomas H. Fletcher for providing CPD model source code.

Notes

∗Stoichiometric ratio, or the mass ratio of actual oxidizer to oxidizer required for stoichiometric conditions.