Segregation phenomena in gravity separators: A combined numerical and experimental study

• In this paper we formulate a computational framework for characterizing and optimizing the performance of adestoner, an example of a density-based separation technique. The numerical framework combines ComputationalFluid Dynamics (CFD) simulations with a Discrete Element Method (DEM), implemented in an opensourcecomputation package (OpenFOAM). This framework is validated first by comparing the simulationswith experiments for a standardized test case and further with our experimental study of a pilot-scale destoner.We evaluate the combined effects of process conditions, such as separator deck inclination, vibration speed andfluidization velocities on destoner performance. Our simulations showhowthe heavy product fraction in the discardsstreamincreases over timewith a corresponding accumulation of the ‘valuable’ light product at the base ofthe deck, indicating segregation between the stones (heavy product) and the grains (light product).We also findthat these separation profiles are highly sensitive to changes in deck surface air velocities, with the gradual developmentof segregation zones at velocities close to the minimum fluidization velocity of the heavier component.Optimal separation is seen at a deck inclination of 4° and a fluidization velocity of between 1.75 and2 m/s. Our simulation results also agree well with the experimental findings indicating the usability of the proposedframework for the design and optimization of gravity separators.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Numerical simulations

Gravity separators

OpenFOAM

Design and optimization

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