Gas phase polymerization process

A continuous process for the polymerization of a polymerizable olefin monomer or a mixture of two or more olefinic monomers by passing a gaseous stream comprised of an olefin monomer or a mixture of olefinic monomers through a fluidized bed in a reactor in the presence of a polymerization catalyst, under reactive conditions, to polymerize at least a portion of said olefin monomer or said mixture of olefinic monomers, which comprises:

• A. withdrawing a gaseous stream from said reactor which is comprised of at least some unreacted olefin monomer or at least some of said mixture of olefinic monomers,
• B. cooling at least a part of said gaseous stream withdrawn from said reactor to a temperature at or below that at which liquid condenses out of said stream,
• C. separating at least part of the condensed liquid from the cooled gaseous stream,
• D. continuously introducing at least a portion of said cooled gaseous stream into said reactor
• E. bringing at least a part of said condensed liquid into indirect heat exchange relationship with said fluidized bed, thereby to produce a heated fluid, and
• F. injecting at least a part of said condensed liquid into the reactor onto a portion of the wall of the reactor which is above or generally peripheral to the said fluidized bed or into a peripheral region of said fluidized bed where the flow of polymer particles within the bed is primarily downward, toward the bottom of the reactor.

A process for producing polymer from monomer by an exothermic polymerization reaction in a reaction zone containing a bed of gas fluidized growing polymer particles which comprises:

• A. continuously passing a gaseous stream comprising monomer through said reaction zone with an upward velocity sufficient to maintain said particles in a suspended and gas fluidized condition;
• B. intermittently or continuously introducing a polymerization catalyst into said reaction zone;
• C. continuously or intermittently withdrawing polymer product from said reaction zone;
• D. continuously withdrawing a stream comprising unreacted monomer gases from said reaction zone;
• E. compressing and cooling said stream to a temperature below the dew point of said stream to form a mixture comprised of gas and liquid;
• F. separating liquid from said mixture;
• G. continuously introducing all or a part of the remainder of said mixture, after separation of liquid from said mixture, into the bottom of said reactor in a region below the said reaction zone;
• and
• H. injecting at least a part of said condensed liquid into the reactor onto a portion of the wall of the reactor which is above or generally peripheral to the said fluidized bed or into a peripheral region of said fluidized bed where the flow of polymer particles within the bed is primarily downward, toward the bottom of the reactor.

A process for producing polymer from monomer by an exothermic polymerization reaction in a reaction zone containing a bed of gas fluidized growing polymer particles which comprises:

• A. continuously passing a gaseous stream comprising monomer through said reaction zone with an upward velocity sufficient to maintain said particles in a suspended and gas fluidized condition;
• B. intermittently or continuously introducing polymerization catalyst into said reaction zone;
• C. continuously or intermittently withdrawing polymer product from said reaction zone;
• D. continuously withdrawing a stream comprising unreacted gases from said reaction zone;
• E. compressing and cooling said stream to a temperature below the dew point of said stream to form a mixture comprised of cooled gas and cooled liquid;
• F. separating cooled liquid from said mixture;
• G. continuously introducing all or a part of the remainder of said mixture, after separation of cooled liquid therefrom, into the bottom of said reactor in a region below the said reaction zone;
• H. bringing at least a part of said cooled liquid into indirect heat exchange relation with said reaction zone, thereby to produce a heated fluid;
• and
• I. injecting at least a part of said condensed liquid into the reactor onto a portion of the wall of the reactor which is above or generally peripheral to the said fluidized bed or into a peripheral region of said fluidized bed where the flow of polymer particles within the bed is primarily downward, toward the bottom of the reactor.