Abstract: There is provided a method for extracting a gaseous fluid which comprises extracting the gaseous fluid through fluid extraction ports set up on the top face portion of a vertical-type agitation tank equipped inside with an agitator, wherein two fluid extraction ports are set up at positions approximately symmetrical about the center of the top face portion of the vertical-type agitation tank, or wherein at least three fluid extraction ports are set up each at a vertex of an approximately regular polygon having the central point identical with the center of the top face portion of the vertical-type agitation tank.

Abstract: There is provided a method for extracting a gaseous fluid which comprises extracting the gaseous fluid through fluid extraction ports set up on the top face portion of a vertical-type agitation tank equipped inside with an agitator, wherein two fluid extraction ports are set up at positions approximately symmetrical about the center of the top face portion of the vertical-type agitation tank, or wherein at least three fluid extraction ports are set up each at a vertex of an approximately regular polygon having the central point identical with the center of the top face portion of the vertical-type agitation tank.

Abstract: Provided is a continuous vapor-phase polymerization method for producing polyolefins. In the method, polymer agglomerates and aggregates are prevented from being formed, and polymer deposition on the wall of reactors and around stirring blades is prevented. The method enables continuous and stable production of high-quality polyolefins, with no pipe line clogging. The method is characterized by a specific supply mode of feeding a catalyst activity retardant such as alcohol into polymerization reactors. Specifically, the retardant is fed into the vapor phase in a polymerization reactor and into the powder phase therein through its side wall. Preferably, the retardant is fed into the powder phase through a plurality of sites of the side wall of the reactor.

Abstract: Provided is a continuous vapor-phase polymerization method for producing polyolefins. In the method, polymer agglomerates and aggregates are prevented from being formed, and polymer deposition on the wall of reactors and around stirring blades is prevented. The method enables continuous and stable production of high-quality polyolefins, with no pipe line clogging. The method is characterized by a specific supply mode of feeding a catalyst activity retardant such as alcohol into polymerization reactors. Specifically, the retardant is fed into the vapor phase in a polymerization reactor and into the powder phase therein through its side wall. Preferably, the retardant is fed into the powder phase through a plurality of sites of the side wall of the reactor.