Based on particle image velocity (PIV) technology and particle diffusion law

the diffusion coefficient of SAPO-34 catalyst particles in turbulent fluidized bed for methanol to olefins (MTO) was studied. A two dimensional transparent glass fluidized bed reactor was used to study the particle diffusion coefficient as functions of operating gas velocity and particle size. The motion of SAPO-34 particles was recorded by high speed camera

based on which both longitudinal and lateral velocities were calculated via image processing technology

hence the diffusion coefficient was obtained according to particle diffusion law. It showed that both longitudinal and lateral diffusion coefficient of SAPO-34 particles (Geldart A) increased with operating gas velocity. The longitudinal diffusion coefficient ranged from 10-3 m2·s-1 to 10-2 m2·s-1

and the lateral diffusion coefficient from 10-1 m2·s-1 to 10-2 m2·s-1. In addition

under the same fluidization operating gas velocity

the particles with smaller particle size possessed larger diffusion coefficient than those with larger one. It is of significance for the research related to the motion law of particles in turbulent fluidized bed.