NOx emission characteristics in rich-lean combustion of hydrogen

Characteristics of NO, formation in a gas turbine fuelled with hydrogen were analyzed with both an experimental and a numerical approach. This research experimentally investigated NO, reduction effect of rich-lean combustion in a coaxial burner. Hydrogen emits no Prompt NO even in rich mixture conditions, and can be more effective to reduce NOx in the rich-lean combustion system than hydrocarbons. The results show that the rich-lean combustion of hydrogen successfully reduces NOx emission compared with diffusive combustion. In the rich-lean combustion, hydrogen combustion has lower NOx emission compared to methane combustion, especially with larger equivalence ratio of richer side mixture. Calculations of NOx formation in the rich-lean combustion were also done employing the extended Zel'dovich NO formation mechanism. (C) 2002 Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V. All rights reserved.