Characteristics of grid zone heat transfer in a gas-solid fluidized bed
The grid zone in a gas-solid fluidized bed reactor has been observed to play a critical role in governing the reactor performance, particularly in shallow and large beds with fast reactions. However, despite its importance the grid zone behavior is far from completely understood, due mainly to its complexity and the few efforts to study it. One of the important aspects on the grid zone behavior is the heat transfer between the bed and immersed horizontal tubes. Although this subject has been under intensive study in the bubbling zone and freeboard area, no systematic work has been performed in the grid zone. Others examined the phenomenon and concluded that the existing heat transfer correlations for the bubbling zone give erroneous results when applied to the grid zone, especially at high velocities. The finding is expected since the two zones are significantly different in their hydrodynamic characteristics. An example of a process involving grid zone heat transfer is the shallow fluidized bed heat exchanger. The exchanger is operated at an extremely low bed height (6-10 cm) with horizontal fin tubes in the grid region. The authors reported a higher than expected heat transfer rate (compared to the bubbling bed heat transfer rate).
- Research Organization:
- Dept. of Chemical Engineering, Lamar Univ., Beaumont, TX 77710
- OSTI ID:
- 5520852
- Journal Information:
- A.I.Ch.E. J.; (United States), Journal Name: A.I.Ch.E. J.; (United States) Vol. 33:5; ISSN AICEA
- Country of Publication:
- United States
- Language:
- English
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