| 摘要 |
<PICT:0897271/III/1> A solution of a solid polyolefin in a hydro carbon solvent is concentrated by heating the solution in preheater 12 and then spraying it through nozzles 14 into flash-chamber 16, the hot solution being sprayed downwards towards the surface of a pool of concentrated polymer solution 18 in the lower part of the flash-chamber. Solvent vapours are withdrawn from the top of the chamber and are condensed in condenser 32; and concentrated solution is withdrawn from the flash-chamber through conduit 22 by means of pump 23. A major part of this concentrated solution is recycled via conduit 26 to feed-conduit 13, where it mixes with fresh preheated dilute solution on its way to the flash-chamber. The remainder of the concentrated solution is withdrawn from the system via line 24, and may be subjected to steam-stripping. The withdrawal of solvent vapours from the flash-chamber is regulated by valve 28 which is actuated by pressure-controller 27. Gaseous unreacted monomer is separated from the condensed solvent in a separator. The process may be employed for separating polyethylene, polypropylene or polybutadiene from solvents such as butane, pentane, iso-octane, cyclohexane, and methylcyclohexane.
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