Polymer devolatilization apparatus
AssigneeNova Chemicals Europe Limited
InventorThomas Orr Craig
Life of this patent
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Abstract
Devolatilization of molten polymer is carried out using a vertical static mixer which opens directly into a flash tank. Expansion of a stripping agent injected at an inlet of the static mixer occurs in the static mixer and the continued shearing causes disengagement of the vapor from the polymer, so that expansion is complete before the polymer enters the flash tank and stripper and volatiles are removed by a pump and condenser arrangement which holds the flash tank at a reduced pressure. Polymer outlets are in the floor of the flash tank and have metering pumps at their bottom end.
Claims10
Apparatus for devolatilisation of a molten polymer comprising:
- (a) static mixer means for receiving an upward flow of molten polymer;
- (b) injection means for charging a stripping agent into the molten polymer at an inlet end of the static mixer means;
- and
- (c) a flash tank having an inlet for receiving a flow of molten polymer-stripping agent mixture from the static mixture means and at least one outlet for removal of devolatilised polymer therefrom, characterized in that an outlet end of the static mixer opens directly into the flash tank.
A method of devolatilising a polymer comprising:
- (i) charging molten polymer under pressure into an inlet end of a static mixer
- (ii) charging a stripping agent into the molten polymer under pressure;
- (iii) passing a flow of the molten polymer-stripping agent mixture upwardly through the static mixer to experience progressively decreasing pressure to an outlet of the static mixer which is at a devolatilising pressure;
- and
- (iv) passing the molten polymer-stripping agent mixture from the outlet of the static mixer directly into a flash tank maintained at the devolatilisation pressure.
Dependencies are inferred from the claim text.