Abstract—A comprehensive 3D Computational Particle Fluid Dynamic (CPFD) model is prepared to study the gas-solid isothermal flow in a riser of a dual fluidized bed biomass gasification system. The fluidizing gas is air, and the particles are olivine, char, and their mixture. The isothermal temperature of the particle and fluid flow is maintained at 1300 K. Bubbling, turbulent and fast fluidization regimes in the reactor with their corresponding velocities are identified. The bed inventory emptying method is implemented to find the transport velocity. Average pressure drop and bed material influx and out-flux are monitored at a wide range of gas velocities to determine the stable flow regimes in the bed for solid transport. The fluidization properties of the bed of olivine particles differ significantly from the bed of the mixture of olivine particles and char particles. Effects of the bottom, primary and secondary air flows on the fluidization regime and particle transport rate have been investigated.
Index Terms—CPFD, fluidized bed, fluidization regimes.
Rajan K. Thapa and Britt M. Halvorsen is with the University College of South East Norway, kjølnes ring 56, 3901, Porsgrunn, Norway (e-mail: rajan.k.thapa@hit.no, britt.moldestad@hit.no).
Christoph Pfeifer is with University of Natural Resources and Life Sciences, Gregor-Mendel-Strasse 33, 1180, Vienna Austria, Austria (e-mail: christoph.pfeifer@boku.ac.at).
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Cite: Rajan K. Thapa, Christoph Pfeifer and Britt M. Halvorsen, "Flow Regime Identification in a Fluidized Bed Combustion Reactor," International Journal of Modeling and Optimization vol. 6, no. 3, pp. 188-194, 2016.