The behavior of trace elements in fluidized bed combustion
- Instituto Nacional del Carbon (CSIC), Oviedo (Spain); and others
The present study focuses on the behavior of major, minor and trace elements during fluidized bed coal combustion, at 850{degrees}C in a 0.14 m i.d. atmospheric reactor. The combustion ashes were continuously taken out of the bed. The rest were elutriated by the combustion gases and collected in two cyclones and a baghouse filter located at the outlet. A low volatile bituminous coal from the Asturian Central basin (North of Spain) was used for the experiments that comprised two tests; with and without addition of limestone. The concentrations of 57 elements were determined in the coal and in the different combustion ashes by ICP-MS, ICP-EAS, and XRF. Elements normally present in the combustion flue gases as vapor, such as Hg and As were sampled in impingners, and determined by cold vapor atomic absorption, and ISO R-601 standard method. Using these methods these elements were not detected in the gas phase. No major differences were observed on the behavior of trace elements during combustion with and without limestone addition. The results show a clear grain size segregation of elements of environmental concern such as As, Co, Cu, Hg, Mo, Ni, Ph, Sb and Se. These elements are enriched in the finest grain size fraction. The grain size partitioning could be attributed to the following processes: (a) physical segregation of major and trace elements in the reactor, due to differences on the distribution of these elements in the feed coal and, (b) chemical segregation due to volatilization and condensation from flue gas.
- OSTI ID:
- 420508
- Report Number(s):
- CONF-960807-; ISSN 0569-3772; TRN: 97:000002-0009
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Vol. 41, Issue 3; Conference: 212. national meeting of the American Chemical Society (ACS), Orlando, FL (United States), 25-30 Aug 1996; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
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