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

, M.Sc. Thesis Sharif University of Technology panjehshahin, Ahmad (Author) ; Molaei, Asghar (Supervisor)

Abstract

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...

Modeling and Simulation Study of Ammonia Decomposition in Assisted-Membrane Fluidized Bed Reactors

, M.Sc. Thesis Sharif University of Technology Khalili, Masoud (Author) ; Molaei Dehkordi, Asghar (Supervisor)

Abstract

Increasing need for energy, non-renewable fossil resources and environmental pollution persuaded investigators to offer hydrogen as a clean alternative fuel. One of efficient methods for producing hydrogen is the ammonia catalytic cracking reaction. The present work the most to caused on the simulation of both 1D and 2D in an assisted-membrane tapered fluidized bed reactor. In 1D simulation several tubes of membrane placed inside the reactor, but in the case of 2D simulation two membrane tubes on the reactor walls were used. In 1D and 2D simulations the compartmental and Eulerian-Eulerian approach were used, respectively. The simulation results indicate that in a constant static bed height,...

Modeling and Simulation Study of Tapered Fluidized-Bed Reactors with Gas Reduction

, M.Sc. Thesis Sharif University of Technology Askaripour, Hossein (Author) ; Molaei Dehkordi, Asghar (Supervisor)

Abstract

Existence of a velocity gradient in the axial direction in tapered fluidized beds causes unique dynamic characteristics of this kind of beds relative to cylindrical fluidized beds. Due to this characteristic, fluidized bed reactors with inclined walls have found a wide application in many industrial processes. In this study, tapered-¬in and tapered-¬out fluidized bed reactors have been simulated using Eulerian-¬Eulerian approach and applying the Kinetic Theory of Granular Flows (KTGF) for solid particles to investigate the bed behavior in the presence of two kinds of chemical reaction with gas volume reduction and gas volume increase. The results of hydrodynamic simulations show that the...