Process for recovery of solid thermoplastic resins from solutions thereof in organic solvents

A process for recovering a thermoplastic polycarbonate or polyphenylene oxide resin from a solution of said resin in a solvent comprising introducing the resin solvent solution into a first separation vessel by a first conduit means terminated with atomizing means in communication with an intermediate region of said first separation vessel and below the surface of the liquid contained therein, supplying additional heat to said first separation vessel from hot recycled water as is hereinafter described, removing a mixture of solvent and water vapor as an overhead product from said first separation vessel by means of a second conduit means in communication with an upper region of said first separation vessel, condensing said overhead product and passing the condensate to a solvent recovery apparatus by means of said second conduit means, removing a bottom product comprising a slurry mixture of said resin, solvent and water from said first separation vessel by means of a third conduit means to a heat exchange apparatus, passing said bottom product through a fourth conduit means communicating from said heat exchange apparatus into a second separation vessel by means of said fourth conduit means in communication with an intermediate region of said second separation vessel, and simultaneously introducing steam into said second separation vessel by means of a fifth conduit means in communication with a lower region of said second separation vessel, removing a mixture of solvent and water vapor as an overhead product of said second separation vessel by means of a sixth conduit means in communication with an upper region of said second separation vessel, recovering the enthalpy of said solvent and water vapor mixture by passing said mixture to said heat exchange apparatus by means of said sixth conduit means in communication with said heat exchange apparatus, effecting an exchange of heat in said heat exchange apparatus between the bottom product entering the heat exchange apparatus by means of said third conduit means and the overhead product of the second separation vessel entering said heat exchange apparatus by means of said sixth conduit means, removing a solvent and water vapor product from said heat exchange apparatus by means of a seventh conduit means and treating said solvent and water product in a solvent recovery apparatus in communication with said seventh conduit means, recovering a bottom product of said second separation vessel comprising a slurry mixture of said resin and hot water by means of an eighth conduit means in communication with a dewatering zone, separating said hot water from said resin in said dewatering zone and recycling said hot water from said dewatering zone by means of a ninth conduit means communicating from said dewatering zone to a tenth conduit means where said hot recycle water is mixed with make-up water entering said first separation vessel by means of said tenth conduit means in communication with an intermediate region of said first separation vessel, and thereafter treating said resin to further dewatering and drying and removing the resin from the dewatering zone by an eleventh conduit means.