The relative importance of the contribution of volatile-N to the formation of NO and N{sub 2}O during the combustion of coal in a FBC
- Univ. Nova de Lisboa, Monte da Caparica (Portugal). Dept. de Quimica
- Inst. Nacional de Engenharia e Technologia Industrial, Lisboa (Portugal). Dept. de Tecnologias de Combustao
The chemistry of nitrous oxide (N{sub 2}O) formation and subsequent decomposition during coal combustion in a FBC still continues to be investigated although a lot of progress has been achieved in recent years. This paper discusses the results of experimental work undertaken to investigate the combustion of volatiles released during the fluidized bed combustion of coals. The combustion of volatiles was investigated in a separate combustor following the devolatilization of coal particles in a fluidized bed under the same heating conditions as in combustion. The levels of NO and N{sub 2}O were determined and were compared with those obtained from burning of parent coals and chars produced during the devolatilization. The analysis of the main nitrogen species released into the gas phase, HCN and NH{sub 3} was carried out. The results confirm that HCN is the main precursor responsible for the formation of N{sub 2}O. It was found that the main source of both N{sub 2}O and NO is the combustion of char, however, the volatiles significantly contribute to the amount of N{sub 2}O formed. Char also appears to give rise to a considerable reduction of both N{sub 2}O and NO during combustion. The presence of volatiles very close to the char particle surface could lead to the suppression of oxidation reactions in the gas phase, thus giving rise to a reduction in the total amount of N{sub 2}O and NO formed.
- OSTI ID:
- 357876
- Report Number(s):
- CONF-9705116--; ISBN 0-7918-1557-9
- Country of Publication:
- United States
- Language:
- English
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