NO Reduction Scale of Three Typical Chinese Coals during Oxy-Coal Combustion

ABSTRACT

Oxy-coal combustion has become one of the most promising technologies for its ability to capture carbon dioxide and produce low pollutant emissions. In particular, the NO emission from oxy-coal combustion is found to be much lower than that in air combustion, but the NO reduction degree varies. In order to ascertain a rough NO reduction potential for Chinese coals, three types of coals (lignite, bituminous coal and anthracite) were combusted in a drop-tube furnace (DTF) in air and oxy-coal atmosphere during this study. The results showed that oxy-coal combustion could largely reduce NO emission down to 50% for the three coals. The NO reducing potential of oxy-coal technology for the lignite was higher than that for the bituminous coal and the anthracite. High content of volatiles in the lignite was considered as the major reason. NO removal was suppressed in the bituminous coal combustion due to the impacts of CaO and Fe₂O₃.