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Temporal release of potassium from pinewood particles during combustion.
- Source :
-
Combustion & Flame . Feb2015, Vol. 162 Issue 2, p496-505. 10p. - Publication Year :
- 2015
-
Abstract
- The temporal release of K from single pinewood particles of four different initial masses (20–50 mg) in a Hencken burner was measured in-situ by laser-induced break down spectroscopy (LIBS). Particle temperature during the combustion was measured by two-color pyrometry. A calculation method was developed to determine the K release flux across the plume based on LIBS measurement and computational fluid dynamics (CFD) model. For all the 4 particle sizes, the temporal release rate of K showed a peak during devolatilization, a monotonous increase during char combustion and a monotonous decrease during the ash stage. It is found that the cumulative fraction of released K was below 4% in the devolatilization stage and ∼20% in the char combustion stage. The particle mass did not have significant influence on the K release. The mechanism of the K release during the char combustion was analyzed, based on the initial portioning of K as inorganic K and organically-bound Char-K. The inorganic K releases mainly by thermal decomposition. The Char-K releases mainly by converting first to inorganic K when the char is burnt and then by releasing to gas phase from the inorganic K. A kinetic model for the release of K during pinewood char combustion was developed on this basis. The kinetic parameters for the release of K was found to be influenced by the initial partitioning between the inorganic K and the Char-K. The correlated initial proportion of inorganic K in pinewood char was found to be 0.37, while the correlated pre-exponential factor and the activation energy for K release were 12.5 1/s and 89.9 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00102180
- Volume :
- 162
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Combustion & Flame
- Publication Type :
- Academic Journal
- Accession number :
- 100156442
- Full Text :
- https://doi.org/10.1016/j.combustflame.2014.07.030