HCN and NH3 Formation during Coal/Char Gasification in the Presence of NO

Understanding the conversion of coal-N during gasification is an important part of the development of gasification-based power generation technologies to reduce NO x emissions from coal utilization. This study investigated the conversion of coal-N in the presence of NO during the gasification of three rank-ordered coals and their chars in steam and low-concentration O2. Our results show that NO can be incorporated into the char structure during gasification. The inherent char-N and the N incorporated into the char from NO-char reactions behave very similarly during gasification. During the gasification in steam, significant amounts of HCN and NH3 can be formed from the incorporated N structure in char, especially for the relatively “aged” chars, mainly due to the availability of abundant H radicals on the char surface during the gasification in steam. During the gasification in 2000 ppm O2, the formation of HCN or NH3 from the N structures in char, including those incorporated into the char from the NO-char reactions, was not a favored route of reaction mainly due to the lack of H on char surface in the presence of O2.