Chemical looping combustion is a new type of flameless combustion technology based on solid oxygen carrier particles

which is of great significance to help carbon emission reduction. The life of oxygen carrier particles restricts the further application of the technology. In this paper

to address the collision wear problem of oxygen carrier particles

the CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) two-way coupling numerical calculation method is proposed. The motion state

distribution characteristics and collision of oxygen carrier particles in a cold fluidized bed are investigated from perspectives of the particle velocity field

collision frequency field

and collision power field. A model of irregular oxygen carrier particles is constructed

which reveals the mechanism of collision wear of the oxygen carrier particles. The results show that the oxygen-carrying particles in the cold fluidized bed exhibit vertical disordered periodic motion

and the dense-phase and dilute-phase zones of particles appear in the fluidized bed space within a single cycle. Among them

the particle velocity in the dilute-phase region is and the collision frequency is low

and the particles have high kinetic energy and high gravitational potential energy; the particle velocity in the dense phase region is low and the collision frequency is high

and the particles corresponding to the maximum collision frequency are mostly of large size

low aspect ratio

and the particle energy is low. The most easily worn area of particles

i.e.

the maximum collision power area (maximum 7.8×10-8 W)

is located at the interface between the dense-phase area and the dilute-phase area. The collision wear energy of particles is provided by the accumulation of kinetic energy and gravitational potential energy of particles. The results reveal the collision wear mechanism of oxygen carrier particles in the cold fluidized bed.