Investigation of the segregation of a binary particle mixture in a square circulating fluidized bed with air staging

To further understand the segregation characteristics of a binary particle mixture in a riser, the flow behaviors of particles with different sizes were experimentally and numerically investigated in a cold square circulating fluidized bed. The impact of the gas velocity, solid circulation rate, initial coarse particle fraction, and air staging on the coarse particle fraction and axial pressure drop were examined. The experimental results show that air staging can significantly promote the pressure drop of a binary mixture at the bottom of the bed compared with that of monosized particles. Meanwhile, the segregation of the binary mixture at the bottom is hindered. It was also found that there was clear radial segregation owing to a higher coarse particle fraction near the wall compared with the bed's center and its corner.