(400b) Interaction Between NO and Char in the Presence of Oxygen

Wenxia Yan^1,2, Songgeng Li^1,2and Cuigang Fan^1,2

¹ Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China

²University of Chinese Academy of Sciences, Beijing, China

NO_x emission from combustion of coal remain a problem of considerable interest. Deep reduction of NO_x has been required to meet more restrict environmental protection regulation in China. Use of carbonaceous materials as a reducing agent for NO removal has the advantages including the inexpensive carbon materials, their abundance and easy availability, very high reduction efficiency without using any catalysts and thus low cost. However, the interaction between NO and carbon is complicated and still under debate although much effort has been devoted in the past decades.

In this process, NO is reduced by carbon. CO, CO2 and N2 are formed. In this work, eleven coal chars are studied in a laboratory scale fixed bed reactor for NO removal. It is found out that the eleven coal chars exhibit different performance in terms of the selectivity of NO-char reaction in the presence of oxygen. Basically, it can be divided into two groups. One group of chars has the positive correlations of CO formation with NO reduction. The other group has completely the inversed trend. Various characterization techniques like XPS, BET and TEM have been employed to examine their physiochemical properties in attempt to give an explanation of this phenomenon. It is found that surface oxygen complexes play an important role. Further, the oxygen species are distinguished and their roles have been elucidated. Their textural and structural properties have also been discussed. Two different reaction mechanisms, i.e., surface carbon-oxygen complexes involved reactions and directly burn-off unoccupied surface, are put forward to explain different performance exhibited by the samples examined in this work.

Contact information： sgli@ipe.ac.cn