The present invention provides a method and apparatus for separating unreacted monomer from a polymerization process effluent stream, wherein the effluent stream comprises unreacted monomer and polymer particles. The method comprises passing the effluent stream of a fluidized-bed reactor into at least one container, feeding a high-pressure olefin through an ejector, and vacuuming at least a portion of the effluent stream from the at least one container through the ejector. The apparatus comprises a fluidized-bed reactor having a first conduit connected to a first tank, an ejector having a second conduit connected to the first tank, and a third conduit connected to the fluidized-bed reactor.