| 摘要 |
With conventional anchor agitators in gas phase polymerisation, powdery polymer tends to adhere to the inner wall of the polymerisation vessel and a vortex is formed at the central part of the fluidised bed zone of the vessel. These problems are overcome by an anchor agitator which has a rotatable shaft (1), at least two pairs of arms (2,2 min ; 3,3 min ) provided on said shaft in mutally crossing positions and a respective agitation blade (4,4 min ; 5,5 min ) provided at the radially outer end portion of each arm, opposed pairs of blades extending substantially parallel to and being located substantially equidistant from the longitudinal axis (X) of said shaft (1); in which one pair of blades (4,4 min ) is a pair of main blades located farther from the axis (x) of the rotatable shaft (1) than a pair of other, subsidiary, blades (5,5 min ) and each of the main and subsidiary blades meet certain geometrical requirements. This anchor agitator can be used in a vessel for the gaseous phase polymerisation of olefins. |
