Abstract Vinyl chloride, alone or with a suitable comonomer, is continuously polymerized under liquid phase bulk conditions in an agitated reactor to a solid polymer content of about 15 weight percent polymer. A portion of the reaction effluent is continuously or periodically withdrawn from the agitated reactor and flashed into a multiple stage gas-phase fluidized bed reactor wherein monomer is employed as the fluidizing gas. Monomer gas is withdrawn from the fluidized bed reactor and a portion thereof is reintroduced into the fluidized bed reactor as the fluidizing gas. An additional portion of the withdrawn monomer gas is condensed and flashed into one or more of the stages within the fluidized bed reactor at a rate responsive to the temperature of the respective stage, thereby removing heat of reaction. The fluidized bed reactor is provided with a plurality of perforated trays with or without downcomers to maintain the corresponding plurality of fluidized beds of polymer particles. A polymerstream is withdrawn from the fluidized bed reactor and passed to a fluidized bed flash tank. Polymer containing only a small amount of monomer is withdrawn from the flash tank and introduced into a multiple stage fluidized bed purge tank with the fluidizing gas being a purge gas.
A process in accordance with claim 1 wherein said reaction effluent stream is withdrawn from said liquid phase agitated reaction zone at a rate to maintain the polymer content in said liquid phase reaction zone less than a predetermined amount.
Claim 2
Dependent Claim
64 words
A process in accordance with claim 2 further comprising passing the polymer particles from said bottom bed into a flash zone to flash a portion of the monomer associated therewith, withdrawing from the overhead of said flash zone an overhead stream of gaseous monomer and withdrawing from the lower portion of said flash zone polymer particles having a reduced amount of monomer associated therewith.
Claim 3
Dependent Claim
54 words
A process in accordance with claim 3 wherein said flash zone contains a fluidized bed, and further comprising compressing and heating a portion of said overhead stream from said flash zone, and introducing the resulting heated compressed gas into said flash zone as the fluidizing gas for said fluidized bed in said flash zone.
Claim 4
Dependent Claim
51 words
A process in accordance with claim 3 further comprising passing the polymer particles withdrawN from said flash zone into a multiple stage fluidized bed purge zone, passing a purge gas through each of the stages in said purge zone, and withdrawing from said purge zone polymer particles substantially free of monomer.
Claim 5
Dependent Claim
109 words
A process in accordance with claim 3 wherein said monomer is vinyl chloride, wherein said polymerization conditions in said liquid phase agitated reaction zone comprise a pressure in the range of about 75 to about 150 p.s.i.a. at a temperature in the range of about 100* to about 150* F., said predetermined amount is 15 weight percent, said reaction conditions in said plurality of gas fluidized beds comprise a pressure in the range of about 60 to about 150 p.s.i.a. at a temperature in the range of about 100* to about 150* F., and the temperature in each of said plurality of gas fluidized beds is substantially the same.