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Hydrodynamic Investigation of Tapered-in Fluidization and Comparison with Tapered-out Fluidized Beds and Cylindrical Fluidized Beds

panjehshahin, Ahmad | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49228 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Molaei, Asghar
  7. Abstract:
  8. Tapered-in fluidized beds, have unique dynamic characteristics compared to cylindrical fluidized beds, because of the velocity gradient in the axial direction. Therefore in the recent years, tapered fluidized beds were widely used in various processes such as biochemical reactions, biological, crystallization, gasification, liquefaction, etc. In this study, a two-dimensional gas-solid model using Eulerian-Eulerian approach along with the kinetic theory of granular solid in a tapered-in fluidized bed was applied. Moreover, the tapered-in fluidized beds were compared with the tapered-out fluidized beds and cylindrical fluidized beds in order to investigate the hydrodynamic behavior of the beds. Operating variables studied in this study include specularity coefficient, tapered angle, initial height of the solid particles, inlet fluid velocity, and density and solid particle diameter. The simulation results indicate that specularity coefficient does not have a significant influence on the pressure drop and volume fraction of solids, however, this parameter is inversly related to the average velocity of solid particles. The obtained results show that by increasing tapered angle in tapered-in fluidized beds the gas bubble diameter is reduced and the pressure loss decreases in all these beds. Also the simulation results indicate that by increasing the density and diameter of solid particles, the diameter of gas bubbles and bed expansion ratio decrease
  9. Keywords:
  10. Bed Pressure Drop ; Tapered Fluidized Bed ; Bed Expansion Ratio ; Eulerian-Eulerian Approach ; Tapered-Angle ; Bubble Diameter

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