CFD-DEM Analysis of Particle Attrition in a Jet in a Fluidised Bed
Abstract
In fluidised bed processes, the solids are in vigorous motion and thus inevitably subjected to
mechanical stresses due to inter-particle and particle-wall impacts. These stresses lead to a gradual
degradation of the particles by surface wear, abrasion and body fragmentation commonly termed attrition.
One significant contribution of attrition comes from the air jets of the fluidised bed distributor. Particles are
entrained into the air jet, where they get accelerated and impacted onto the fluidised bed particles. The jet
induced attrition only affects the part of the bed which is limited by the jet length, where the mode of attrition
is largely collisional. The overall jet attrition rate is therefore the result of the combination of the single particle
damage and the flux of particles entering into that region. The attrition behaviour of particles in the jet region
is analysed by evaluating their propensity of breakage experimentally and by simulating an air-jet in a bed of
particles by CFD-DEM. The frequency of collisions and impact velocities are estimated from which the
attrition due to a single air-jet is predicted.
Domains
Chemical engineering
Origin : Files produced by the author(s)
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