Study on heat transfer characteristics of the high temperature reheater tube panel in a 300 MW CFB boiler with fluidized bed heat exchanger

•A cell model for the ash-side heat transfer behavior in the FBHE was developed.•Ash-side heat transfer coefficient profile along ash flow direction in FBHE was obtained.•The 3rd and 4th tube panels of chamber II had the highest outer wall temperature.

On the basis of measurements on the fluidized bed heat exchanger (FBHE) of a 300 MW lean-coal-fired circulating fluidized bed (CFB) boiler under different thermal loads and numerical calculation for steam mass flow rate distribution inside the high temperature reheater (HTR) tube panels, the ash-side heat transfer coefficient distribution along the ash movement direction inside the FBHE was obtained in this paper. A cell model with energy and material balances was also developed for the FBHE. The measured and calculated results indicate that the post-combustion phenomenon exists in the FBHE. The ash-flow movement inside the FBHE has an important impact on the bed-to-tube heat transferring process. Specifically, along the ash moving direction, steam temperature at the outlet of corresponding tube panel decreases gradually, as well as the local ash-side heat transfer coefficient. These results can provide referential materials for design and operation of the FBHE in large-scale CFB boilers.

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