Fuel nitrogen conversion and release of nitrogen oxides during coal gangue calcination

Zhang, Yingyi; Ge, Xinlei; Liu, Lili; Wang, Xidong; Zhang, Zuotai

Fuel nitrogen conversion and release of nitrogen oxides during coal gangue calcination

2015

Zhang, Yingyi | Ge, Xinlei | Liu, Lili | Wang, Xidong | Zhang, Zuotai

The pollution emission during the widespread utilization of coal gangue in construction industry has long been neglected. In present study, the NO ₓ release behaviors in a simulation experiment of coal gangue calcination in construction industry were systematically investigated. The corresponding evolution of nitrogen functionalities in coal gangue was also discussed. Results showed that pyrrolic (N-5) and pyridine N-oxide (N-6-O) forms nitrogen were relatively abundant in the raw gangue. During calcination, the N-5 and N-6-O form nitrogen greatly decreased and converted to quaternary nitrogen (N-Q). It was found that NO₂was formed under slowly heating-up condition and at 600 °C under isothermal condition, while only NO was detected with further increase of temperature. From 600 to 1000 °C, the conversion ratio of fuel nitrogen to NO ₓ increased from 8 to 12 %. The char nitrogen was found greatly contribute to NO formation, which may bring difficulty to the abatement of NO ₓ emission during coal gangue calcination.

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