Particle velocity distributions were investigated in draft tube and annulus region of a φ600 mm CSVQS cold-state setup under conditions of gas velocities at 0.2 and 0.3 m·s-1 in the draft tube

at 0.03 and 0.07 m·s-1 in the annulus region and 0 and 0.13 m·s-1 in the stripper. Mean residence time distribution of particles in the pre-tripper section was also calculated by the method proposed here. Experimental results demonstrated that gas flowed as center-airlifting circulation in the pre-stripper section and most of the gas went into the draft tube under the above-stated operating conditions. Under constant gas velocity in the draft tube and increased gas velocity in the annulus region

the radial velocity distribution of particles changed from steep to smooth without stripper wind whereas that distribution changed slightly with stripper wind. Under the same gas velocity in the annulus region and increased velocity in the draft tube

the radial velocity distribution of particles changed from smooth to steep without stripper wind whereas distribution remained quite steep with stripper wind under the two different velocities in the draft tube. Compared to that in the draft tube

the radial velocity distribution of particles in annulus region kept almost no change with varied operating conditions. When the gas velocity was increased in the draft tube or was decreased in the annulus section

the average residence time distribution of particles was narrowed and the mass fraction of particles was decreased. When the circulation strength of particles in the pre-stripper section was increased

the average residence time distribution of particles was narrowed but the mass fraction of particles was changed irregularly.