Abstract
This paper focuses on assessment of the effect of flue gas recirculation
(FGR) on heat transfer behavior in 1296t/h supercritical coal-fired
circulating fluidized bed (CFB) combustor. The performance test in
supercritical CFB combustor with capacity 966 MWthwas performed with the
low level of flue gas recirculation rate 6.9% into furnace chamber, for
80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary
air to the primary air SA/PA = 0.33. Heat transfer behavior in a
supercritical CFB furnace between the active heat transfer surfaces
(membrane wall and superheater) and bed material has been analyzed for
Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed
material used in the heat transfer experiments had particle density of
2700 kg/m3. A mechanistic heat transfer model based on cluster renewal
approach was used in this work. A heat transfer analysis of CFB combustion
system with detailed consideration of bed-to-wall heat transfer
coefficient distributions along furnace height is investigated. Heat
transfer data for FGR test were compared with the data obtained for
representative conditions without recycled flue gases back to the furnace
through star-up burners.
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