The Characteristics of Recycled-NO Reduction in O

O2 /CO2 coal combustion is a promising technology for easy CO2 recovery and low NOx emission. O2 /CO2 coal combustion system has very high CO2 concentration, and so O2 /CO2 ratio is very important parameter in this system. In this study, the effect of CO2 concentration on recycled NO reduction was investigated experimentally and numerically. It was revealed that the recycled NO reduction ratio was increased with decreasing CO2 concentration. This was because high CO2 concentration enhanced the reaction to produce OH radical (CO2 + H → CO + OH). Both calculations and experiments showed OH radical increased with an increase in CO2 concentration. However, increasing OH radical enhanced the consumption of H2 which is needed for the reduction of secondary NO. It was shown that high CO2 concentration inhibits recycled-NO reduction from the new point of CO2 reactivity.Copyright © 2011 by ASME