Reactor for a gas-phase olefin polymerization

A reactor for carrying out a gas-phase olefin polymerization in the presence of a polymerization catalyst comprising:

• (i) a first polymerization zone adapted and arranged for growing polymer particles to flow upward under fast fluidization or transport conditions,
• (ii) a second polymerization zone adapted and arranged for the growing polymer particles to flow downward, and
• (iii) a set of bars for introducing feedstock or a barrier stream into the second polymerization zone,
• wherein each bar comprises
• (a) a hollow space along the length of the bar for conveying the feedstock or barrier stream within the bar,
• (b) a particle deviating top for preventing accumulation of the polymer particles on the bars, wherein the particle deviating top of the bar includes a top edge which extends along the length of the bar, and
• (c) a multiplicity of openings for distributing the feedstock or the barrier stream,
• wherein the openings being arranged along the bottom half of the periphery of the bar.