Abstract：The flow behaviors of silica sand with the mean diameter of 0.347 mm and the bulk density of 1 435 kg/m³ in the riser were investigated with different loop seals and different exits of the riser at pressure from 0.1 to 0.5 MPa on a cold-model experimental facility of pressurized circulating fluidized bed with the riser diameter of 300 mm and the height of 8 700 mm. The results show that at the elevated pressure, the apparent solid holdup is lower at the upper part and higher at the bottom part of the riser, the apparent solid holdup tend to an uniform distribution with the increase of the superficial air velocity. When the bed inventory and superficial air velocity are kept unchanged, the solid holdup at the upper part of the riser increases with the elevated pressure. Normal circulation process can be established with both the loop seals with the diameters of 150 mm and 200 mm, the solid holdup distribution in the riser can not be changed with the diameter variation of the loop seals. The apparent solid holdup at the top of the riser can be increased with an abrupt exit of the riser.

Keywords: pressurized coal gasification; pressurized circulating fluidized bed; cold-model experimental facility; apparent solid holdup