276414 Numerical Simulations and Experiments On Heat Transfer Around a Probe in the Downer Reactor of a Triple-Bed Combined Circulating Fluidized Bed

Thursday, November 1, 2012: 4:27 PM
Conference B (Omni )
Yongpan Cheng1, Guoqing Guan2, Masanori Ishizuka3, Chihiro Fushimi4, Atsushi Tsutsumi3 and Chi-Hwa Wang5, (1)Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore, (2)North Japan Research Institute for Sustainable Energy (NJRISE), Hirosaki University, Hirosaki, Japan, (3)Institute of Industrial Science, The University of Tokyo, Tokyo, Japan, (4)Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan, (5)Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore

Due to very short residence time in the downer, heat transfer performance inside it has great significance for coal gasification. In this study heat transfer around a heating probe in the downer of a circulating fluidized bed was studied through both experimental and numerical work. Both experimental results and numerical results revealed that average heat transfer coefficients decreased with the increasing superficial air velocity or decreasing solids mass flux, which could be attributed to the decreasing solids holdup, as particle convection was dominant in the heat transfer mechanism under current cases. Numerical simulation also revealed that heat transfer may deteriorate with the increasing particle size. Finally it was found that the heat transfer performance with constant temperature boundary condition around the probe was much better than that with constant heat flux boundary condition. These results may help us better understand the heat transfer in the downer and design downer with high efficiency.

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See more of this Session: Circulating Fluidized Beds
See more of this Group/Topical: Particle Technology Forum