US EPA

1548997 

Journal Article 

Effects of ammonia substitution on combustion stability limits and NOx emissions of premixed hydrogen-air flames 

Joo, JM; Lee, S; Kwon, OC 

2012 

Yes 

International Journal of Hydrogen Energy
ISSN: 0360-3199 

37 

8 

6933-6941 

10.1016/j.ijhydene.2012.01.059 

WOS:000303952300066 

The combustion stability limits and nitrogen oxide (NOx)
emissions of burner-stabilized premixed flames of ammonia (NH3)-substituted hydrogen (H-2) air
mixtures at normal temperature and pressure are studied to evaluate the potential of partial NH3
substitution to improve the safety of H-2 use. The effects of NH3 substitution, nitrogen (N-2)
coflow and mixture injection velocity on the stability limits and NOx, emissions of NH3-H2-air
flames are experimentally determined. Results show a reduction of stability limits with NH3
substitution and coflow, supporting the potential of NH3 as a carbon-free, green additive in H(2
-)air flames and indicating a different tendency from that for no coflow condition. The NOx
emission index is almost constant even with enhanced NH3 substitution, though the absolute value
of NOx emissions increases in general. At fuel-rich conditions, the NOx emission index decreases
with increasing mixture injection velocity and the existence of coflow. The thermal deNO(x)
process in the post-flame region is involved in reducing NOx emissions for the fuel-rich flames.
Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights
reserved. 

Hydrogen; Ammonia; Premixed flames; Combustion stability limits; NOx emissions