This disclosure describes processes for producing polymer using non-polar and condensable stripping agents to remove volatile components, such as solvent and unreacted monomer, from the produced polymer. Systems for performing these processes are also disclosed.

The present invention relates to a process for producing water-absorbent polymer particles by polymerizing droplets of a monomer solution comprising less than 0.3% by weight of persulfate and at least 0.05% by weight of azo initiator and thermal aftertreatment of the formed polymer particles at less than 100° C. in a fluidized bed for 60 to 300 minutes.

Provided is a method of purifying polyolefin, the method including the step of contacting linear low-density polyethylene synthesized by a gas phase polymerization reaction with a purge gas containing an ethylene gas and an inert gas in a purge bin. According to this purification method, residual alkene monomers with high carbon numbers may be removed in a simpler and more efficient manner.

Provided is a method of purifying polyolefin, the method including the step of contacting linear low-density polyethylene synthesized by a gas phase polymerization reaction with a purge gas containing an ethylene gas and an inert gas in a purge bin. According to this purification method, residual alkene monomers with high carbon numbers may be removed in a simpler and more efficient manner.

Provided is a method for producing a purified fluoropolymer containing less fluoridable end groups. The production method includes: (a) melting a fluoropolymer to give a molten fluoropolymer; (b) reducing a reaction inhibitor in the molten fluoropolymer; (c) bringing the molten fluoropolymer into contact with an active substance after the step (b); and (d) removing a volatile matter from the molten fluoropolymer after the step (c).

Provided is a method for producing a purified fluoropolymer containing less fluoridable end groups. The production method includes: (a) melting a fluoropolymer to give a molten fluoropolymer; (b) reducing a reaction inhibitor in the molten fluoropolymer; (c) bringing the molten fluoropolymer into contact with an active substance after the step (b); and (d) removing a volatile matter from the molten fluoropolymer after the step (c).

A vessel header includes lateral flow tubes arranged in a parallel configuration. The lateral flow tubes enter the vessel header through alternating vessel header penetrations with a single vessel header penetration per lateral flow tube. Each lateral flow tube has a perforated section within the vessel header having a non-circular cross-section having the shape of a circular sector, an elliptical sector, or an irregular quadrilateral. A method includes passing a molten polymer through the lateral flow tubes of the vessel header. The molten polymer exits the lateral flow tubes as strands through perforations in the lateral flow tubes within the vessel header. The method includes obtaining devolatilized polymer.

A vessel header includes lateral flow tubes arranged in a parallel configuration. The lateral flow tubes enter the vessel header through alternating vessel header penetrations with a single vessel header penetration per lateral flow tube. Each lateral flow tube has a perforated section within the vessel header having a non-circular cross-section having the shape of a circular sector, an elliptical sector, or an irregular quadrilateral. A method includes passing a molten polymer through the lateral flow tubes of the vessel header. The molten polymer exits the lateral flow tubes as strands through perforations in the lateral flow tubes within the vessel header. The method includes obtaining devolatilized polymer.

Polymerization unit for producing polymer powder having at least one polymerization reactor for the polymerization of light (co)monomer(s) having less than 7 carbon atoms, and heavy comonomer(s) having at least 7 carbon atoms, and a degassing section including two (and optionally a third) cylindrical degassing vessels in series. Light (co)monomer(s) are degassed in the first degassing vessel (V1) and recovered, and heavy comonomers are degassed in the second degassing vessel (V2) and recovered. The active polymer powder is optionally polished and/or optionally deactivated in the optional third degassing vessel (V3). The cross-sectional area (S2) of the second degassing vessel is greater than 1.5 times the cross-sectional area (S1) of the first degassing vessel [S2>1.5×S1], and vessels V1 and V2 are equipped with a vent recovery unit (VR) for respectively recovering the light (co-)monomer(s) (VR1) and the heavy comonomer(s) (VR2) from the gases exiting the vessels.

Polymerization unit for producing polymer powder having at least one polymerization reactor for the polymerization of light (co)monomer(s) having less than 7 carbon atoms, and heavy comonomer(s) having at least 7 carbon atoms, and a degassing section including two (and optionally a third) cylindrical degassing vessels in series. Light (co)monomer(s) are degassed in the first degassing vessel (V1) and recovered, and heavy comonomers are degassed in the second degassing vessel (V2) and recovered. The active polymer powder is optionally polished and/or optionally deactivated in the optional third degassing vessel (V3). The cross-sectional area (S2) of the second degassing vessel is greater than 1.5 times the cross-sectional area (S1) of the first degassing vessel [S2>1.5×S1], and vessels V1 and V2 are equipped with a vent recovery unit (VR) for respectively recovering the light (co-)monomer(s) (VR1) and the heavy comonomer(s) (VR2) from the gases exiting the vessels.