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Title: Heat transfer and hydrodynamic analysis in an industrial circulating fluidized bed boiler

Conference ·
OSTI ID:245047
;  [1];  [2]
  1. Electricite de France, Saint-Denis (France)
  2. Electricite de France, Villeurbanne (France)

In order to scale-up Circulating Fluidized Bed boilers (up to 600 MWe), Electricite de France has initiated a Research and Development program including: laboratory work on mock-up, numerical modeling and on-site tests in the 125 MWe CFB Emile Huchet plant. This paper is devoted to on-site measurements analysis in two main components of this industrial unit: the external fluidized bed heat exchangers and the backpass. This study particularly concerns hydrodynamics and heat transfer with the final target of developing a physical model of a CFB unit. The first part of this paper describes the specific instrumentation set up on external fluidized bed heat exchangers. The comparison between experimental data collected on these heat exchangers and the theoretical heat transfer models mainly used, shows a great difference about the value of the overall heat transfer coefficient. To explain this discrepancy, the particle flow pattern initially used in the thermal balance calculation is modified and a solid bypass is introduced. The analysis of the by-pass behavior, connected to the geometrical and operating parameters of each exchanger, confirms the particle flow pattern suggested. The second part of this paper shows an analysis of the specific measurements set up on the backpass to study heat transfer. The physical model of heat transfer used to assess the importance of each convection, radiation and conduction components is presented. This model allows one to assess the influence of heat exchangers design on heat transfer. Moreover, the analysis of heat transfer variations during sweeping cycles gives the amount of dust that is removed from the heat exchanger tubes. These results are used to evaluate the amount of power that can be recovered by optimizing both design and sweeping of the backpass.

OSTI ID:
245047
Report Number(s):
CONF-950522-; ISBN 0-7918-1305-3; TRN: IM9627%%413
Resource Relation:
Conference: 13. international conference on fluidized-bed combustion, Orlando, FL (United States), 7-10 May 1995; Other Information: PBD: 1995; Related Information: Is Part Of 13. international conference on fluidized bed combustion: Proceedings. Volume 1; Heinschel, K.J. [ed.] [Air Products and Chemicals, Inc., Allentown, PA (United States)]; PB: 719 p.
Country of Publication:
United States
Language:
English