EFFECT OF COMBUSTION AIR DILUTION BY WATER VAPOR OR NITROGEN ON NO_x EMISSION IN A PREMIXED TURBULENT NATURAL GAS FLAME: AN EXPERIMENTAL STUDY

摘要

A study of the effects of combustion air dilution by water vapor or nitrogen on NO_x emission in a premixed turbulent natural gas flame was performed for lean conditions. NO_x concentrations were measured with dry air, water vapor dilution or nitrogen dilution of the combustion air at varying air factor at three different power/ pressure settings. Results showed for all cases a significant reduction in NO_x emission as an effect of combustion air dilution by water vapor and nitrogen for constant T_(ad). The results also showed that the reducing effect of water vapor dilution is larger than the reducing effect of nitrogen dilution. It is therefore concluded that water vapor dilution of the combustion air not only reduces NO_x emission in premixed turbulent flames by lowering flame temperature and oxygen deficiency, but also by chemical action.