Numerical investigations of a pseudo-2D spout fluidized bed with draft plates using a scaled discrete particle model

Spout fluidized beds are often utilized for the gas-solid operations involving physical and/or chemical transformations such as drying, coating, granulation, combustion, gasification, etc. This is because these beds combine advantages of both spouted and fluidized beds. Following the spout fluidized bed development, several geometrical modifications have been proposed to optimize the bed performance. One of the modifications includes a draft tube insertion inside the bed, which results in improved performance by providing a restriction on particle cross flow. Moreover, the draft tube insertion leads to a stable spouting at lower flow rates, due to the reduced inlet gas bypassing (from spout to the annulus).In this work, a discrete particle model (DPM) with a sub-grid scale (SGS) turbulence model was used to simulate the bed dynamics and analyze the effects of the draft plates and particles physical properties by considering two regimes namely, the spouting-with-aeration and fluidized bed-spouting-with-aeration (dispersed spout), which are of interest from an industrial point of view. The obtained results were compared with our experimental data (Sutkar et al., 2013b) from particle image velocimetry (PIV) and digital image analysis (DIA). Furthermore, an alternative simulation approach has been used to simulate dynamics of the industrial scale gas-solid contactors consisting very large particles with reduced total computational time by changing the physical properties of the particles to maintain constant Archimedes and Reynolds numbers. The obtained results were compared with the experimental data, as well as with simulation data obtained with the original physical properties.

Subjects

CFD

Coarse graining

Discrete particle model

Draft plates

Fluid mechanics

Spout fluidized beds

DDC Class

540: Chemie

600: Technik

620: Ingenieurwissenschaften

More Funding Information

Dutch Technology Foundation STW, Applied Science Division of NW

Technology Program of the Ministry of Economic Affairs in The Netherland

Deutsche Forschungsgemeinschaft (DFG)

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Numerical investigations of a pseudo-2D spout fluidized bed with draft plates using a scaled discrete particle model